I have been plumbing 27 years and have installed many electric water heaters , my latest installl the water heater had a a dryer cord used for the power supply that plugged into the wall I wired the giant pigtail while waiting for the old water heater to drain which was full of calcium. I installed the new water heater and removed air from the the line by opening the tub valve. I switched on the power and had a short. The ground screw had pierced the dryer cord on the inside and caused the short but it took awhile to find this out. Lesson learned be wary of giant pigtails.
Yes thanks for sharing. Some years ago a cord and plug connection served as a means of disconnect if the breaker or fuse panel is not within sight of the unit, to protect someone repairing the water heater from being electrocuted if someone else turns the power on. Electric water heaters are not UL listed for cord and plug connection and I don't know that they ever were, nonetheless I have see it done a couple of times in homes 30 years old or more. Instead the unit should be hardwired with 10 guage copper wire connected to a disconnect safety switch or a double pole toggle switch rated for 30 amps near the unit if the breaker box is not within sight.
Great video, my water heater wiring looks like the one in the video, it's 4500w with 10awg on 30 amp . What I can't figure out is the wires that came in the unit that go to the two heating elements are 12 awg. How is that ok on a 30 amp breaker?
The circuit wires should be #10 copper for a typical 30amp water heater. You may consider upgrading the circuit. In the mean time the #12 wire should be on a 20amp breaker - something for you to consider.
@@AskTheElectricianBut that's not what he's really asking... He's asking why does the factory put 12/2 AWG wire coming out of the water heater's from the elements that's supposed to be wiring to 10/2 AWG 30 AMP 2 pole breaker? My new water heater is a AO Smith 40 gallon 30 AMP 2 pole breaker 240volts, and it also has 12/2 AWG wire coming from the unit? I do however have a question? My main panel is a 100 AMP panel box. It has a 12/2 AWG wired to a 30 AMP circuit feeding about 10 to 12 ft or less to a junction box, another piece of wire I can't tell if it's 12/2 AWG or 10/2 AWG running into a 4 circuit sub panel with only 2 circuits being used. A 20 AMP circuit and a 30 AMP circuit 2 pole breaker. The feeding Hot wire is wired to 1 lug, the Neutral to 1 lug and ground to bus bar. The 20 AMP circuit is wired to 2 receptacles that no longer works, it wired to Hot to circuit, neutral and ground to bus bar. Can I disconnect the 20 AMP circuit? And is a water heater supposed to be getting power this way? The old water heater was wired this way for more than 20 year's? I'd appreciate if you could help or give me some insight?
The water heater has 2 heating elements, 1 at top, 1 at bottom. Each element does not use 4500watts, however if both heating elements are on at the same time they together will draw 4500 watts (or less depending on the specific water heater and the factory settings for each heating element). So because each of these elements consume less watts they are wired with the smaller #12 wire.
First let me insert this here: The water heater has 2 heating elements, 1 at top, 1 at bottom. Each element does not use 4500watts, however if both heating elements are on at the same time they together will draw 4500 watts (or less depending on the specific water heater and the factory settings for each heating element). So because each of these elements consume less watts they are wired with the smaller #12 wire. Now as for your other question, no, typically a water heater circuit is a dedicated circuit which is installed from the panel directly to the water heater location. The circuit and sub panel you are referring to sounds very questionable and should be inspected to figure out just what is going on, and how or if it should be used. The wiring is in place, but it needs the purpose needs to be determined. PS - Yes I do answer Questions here, even though this is for Comments, and that's OK, but remember that you can go to ask-the-electrician.com for a LOT more info, and asking a question there will bring you more resources.
My water heater was installed over a year ago cord gets really hot at the base when the hot water is used every time. It omits an order. Not sure if the installer connected correctly or a faulty cord, etc.
I have a 240V dual element 28 gal tank. I have a line coming into it coded Black /white/ground. There is a red & black wire from the tank. Which color from the tank is connected to the black wire coming in, and the white wire coming in.
As noted in the video - when the incoming black and white are the 240volt wires, they connect to the black and red wires of the water heater, respectively.
In our old house, there is the disconnect box with fuses you talk about, I guess I can just remove it. The heater is right beside the break panel. The celling is not finished there (and it wont be) so I'm not sure how long should the metal wire conduit be. I guess about until were the drywall would be if the celling was done?
when voltage testing this assembly at the top of the water heater, what should the readings be? i would expect 120v between black and ground, 120v between red and ground, and some random small number like 10v between red and black. are the red and black voltages then added in series, to get 240v, inside the water heater electrical panel?
@@AskTheElectricianthank you for taking the time to reply to my question. This baffles me especially if you follow the supplied wires in the junction box of the hot water heater down about 18” to where they screw down to a terminal at the upper element/thermostat. Seems as tho you could eliminate an extra splice by running the 10/2 right to the terminal. The most convenient would be a nice terminal block in the upper built-in compartment of the water heater, but like you said… it would add a little extra cost. Personally… I would find it well worth the money.
My current hot water tank is not grounded, and there’s not available wire to ground it. It was already in a house that I bought. I’m replacing the hot water tank today, and I’m wondering if i need to ground the new one, or not?
Just to verify if I have a black and a white wire plus ground do I use my white as a power conductor and that would be fastenened on the one breaker screw?And it doesn't matter which one ,right?
In the USA, for a typical 240volt 30amp water heater circuit in an older home, where the wires are black, white and a bare copper or a green ground wire, in many installations the white wire was used as a power wire and attached to one terminal of the 2pole circuit breaker, and the black wire on the other terminal of the 2pole circuit breaker, and no - it does not matter which position these wires are in as attached to the 2pole circuit breaker. It is always best to identify the white wire as a power conductor using red electrical tape at the circuit breaker and at the water heater. Make sure to verify the circuit wiring as described.
Ok I have a white black and bare copper wire for ground from breaker and red black and green wires on water heater the black is hot on the house wire and white is neutral or negative and which wire red or black is negative or positive on the water heater because ground is green for sure trying to find out if the black on the water heater is the negative or the hot because the black on the house is hot so it would be backwards can't find a picture or anyone stating this definitive statement?
question concerning wiring.? My electrical panel has a 30 amp breaker attached to a 10/3 wire which goes to the water heater space, but the water heater an AO Smith 100 only has 2 wires from it a red wire and a black wire. plus ground of course ,but my question is do I at the water heater tie wiring black to black and white to red or red to red and black to black then using a wire nut to cap off the white wire?
Typically when there is a 10/3 with ground to a water heater the white wire is not used, therefore it is capped off, then all the connections are color to color. It is best to verify the wiring to make sure the black and red wires are in fact the power wires, as they should be.
Thanks for the video. I know this may be a code question so mileage might vary. Running the wire from the ceiling to the tank, or alternately, from a junction box to the tank, does it have to be shielded with the metal tubing as you've shown or can we just run the wire as is, with plastic sheathing still on, right to the tank?
@@AskTheElectrician I'm going to use a liquid tight flexible plastic sheath, used for outdoor applications usually. I just don't like the idea of a metal sheathing for electricity.
@@AskTheElectricianA video by a self described inspector stated that BX is not appropriate. Is there another flexible metal jacketed type of product? I’ve seen a few websites that don’t offer much help in differentiating.
Just wanted to say nice info on the water heater video. Just a question now for you, I'm in going to install a new water heater in our mobile home but the wire is 12 gauge and to short. New heater is taller than the old one. Whats the best way to rewire this with 10 gauge?
Thank you, glad the video was helpful. Double check the electrical circuit specifications on the new water heater to make sure it requires a 30amp circuit, only because not all water heaters are alike, and some for mobile homes may be small - so check this. If a new circuit is required then a new cable may be required to be installed from the water heater to the electrical panel, all according to code. If the existing water heater circuit will not be used then it may be disconnected and removed, and the new circuit breaker could take it's place. The qualified installer will need to be aware of all applicable codes that apply to the project.
I want to install a new electric water heater and remove the gas water heater, however the gas furnace piping is attached. I'm hoping to place the new electric water heater in the garage. How much would a job like that run of adding new wiring, relocating pipes from the inside wall to the interior of the garage cost? And would the mechanic need a permit from the city?
The cost would depend on where you are located, the cost of the materials, and the current labor charges for your area. Get at least two bids from local licensed contractors who have excellent references.
I understand should be three wires two hot with ground..in this house we have red black green and white. So, please how to wire that white wire? I know red to red // black to black// green to ground .that that white wire tie together with red or what ? Thank you,
What do you do when have 8 gauge aluminum wire going to the water heater that has 10 gauge copper whip. I'm thinking Polaris 2 port 4-14awg insulated tap connector. They are rated for Aluminum and copper. I had a plumber wire mine in with wire nuts burned the wire up into the wall I was extremely lucky the strain relief forced it to pull enough current to trip the 30 amp breaker before it got into my attic would have burned my house down. I had the electrician install a disconnect at the water heater this was several years ago before I knew about those Polaris connectors. He wanted to use those purple wire nuts I told him he was crazy never allow wire nuts again with AL and CO wire. The disconnect uses lugs and is rated for AL and CO he agreed to that. My understanding that even though branch aluminum wire has been banned still used for home runs like stoves, water heaters, and dryers. My 1970's house has AL branch wire I'm in the process of pig tailing using alummicons busbars are UL listed for AL and copper very good products well worth the money. Once I pigtail replace every switch and recep put the alumicons in going to replace my breakers with Arcfault gfci breakers I will be able to sleep at night knowing the AL wire is safe in my house.
Wow wow wow,.Señor Dave Rongay..what an excelente video.,looking for info on how to install my Water heater never expected to find such a jewel of info ..Muchas Gracias ,Señor. You made me a happy man today
Hi, great video. Follow up Qs, Should all the wires after the feed lines 1 & 2 are #10 ga should all the other wires from Tstats to elements be #10 as well? I seem to remember #12 ga being used over the years but not sure that is correct? This hwh was wired right except for the black wire from the lower Tstat was on the upper Tstat left side bottom screw and the upper element had its wire on the upper Tstat right side bottom screw. So, they were reversed and that would seem to cause the lower element to come on, but the top I don't think it would ever come on? What is your opinion?
The internal wiring of a typical water heater is factory wired, therefore the installer only has to be concerned with the main circuit connections. The only time we would need to access the other areas is if the water heater element, or one of the controls becomes faulty and needs to be replaced. But you are correct, some of the internal wiring is not #10 because there are two elements that do not pull 30amps each. Great questions - Thanks for viewing the video and sharing your thoughts.
It's not so much the size of the wire that determines how many amps can flow as the temperature rating of the insulation. That's why the wires in the unit are smaller than the supply wires. You can get some really high temp insulation, like asbestos cloth like is used in ovens.
Hello, so I'm in the process of replacing my sister's old 2008 water heater that just started leaking this weekend. As I was inspecting the whole area around the water heater, I noticed the electrical wiring (with romex) for the water heater, was coming out of the floor (just a hole drilled through the wood flooring with no grommet) and free floating up and over to the top of the existing water heater. Would using flex and then securing that along the closest wall be a good way of protecting the wire?
@@AskTheElectrician hello, I have the same situation in my house. My question is if we are allowed to run the romex through the conduit as is or do we have to strip the outer jacket once it transitions to flex conduit?
Is it normal for the water heater to have 12 gague wires that hook up to 10 gauge power wires? I'm stuck at this step, I'm switching from a gas water heater and using a former ac power line that is 10-2 wire from a dual 30 Amp breaker. It feels strange to me that the water heater has 12 gauge wire to meet my 10 gauge. Is this normal?
If there is are two green ground screws (one inside the compartment like your example and one on the top cover plate) does it make any difference which ground screw you use?
Personally I think there should be, however since a typical water heater is a permanent installation with (almost) no parts to service, up to now the NEC does not require a disconnect. Note that the newer hybrid water heaters may require a disconnect.
Water and rust is in the wires cover box. Cover lid is rusted. Water came up through hole. Can this be cleaned up? Its a 2010 Ao Smith electric? Did water come up because its all rusted or just that?
The water heater should be checked to make sure there are no water leaks. It may be that there was a water leak in the past, possibly one of the water pipe fittings above the unit. You may consider turning off the circuit power and cleaning the area and removing the rust to make sure the unit is kept in good condition.
Personally I think a disconnect is a great idea, however since a typical water heater is a permanent installation with (almost) no parts to service, up to now the NEC does not require a disconnect.
I have an old wire coming out of the breaker box. Black and white are hooked on the top screw of the Breaker.. the red wire hooked on the bottom of the breaker. Where does the red wire hook too in the hot water heater?
Question my husband and I was putting our new electric water in and when we removed pipe all of the water was not drained so it leaked overt the electric plate with the neutral ground cords . Now we did blow dry it but should we still water a day before restarting electricity
For the older homes, if the cable has Black, Red, and White insulated wires that are fed directly from the main electrical panel, and the White wire is bonded to the grounded terminal bar then using the White wire as the ground wire is OK, but the white wire should be marked with green tape or a green marker at each location.
You could check the specification label to see what size circuit is required, but if your water heater has been working fine as it is, then there is no need to change it.
The element may be faulty. If this is a new water heater double check to make sure the water is turned on, and bleed out trapped air by running water to other areas of the home.
Great video and highly informative. I reviewed my BradfordWhite service manual which says the following in regards to diagnosing the heating ellement: "Reading should be 12.8 ohms (±6%) for a 240volt, 4500 watt element. A reading outside the range using the formula above (±6%), indicates a bad element and the element must be replaced." So I checked both upper and lower elements and my multimeter shows 12-13ohms initially and as I held the multimeter on the contacts the reading dropped to 9.5ohms after 4-5secs. Im not sure whether to go by the initial 12-13ohm reading or the 9.5ohm reading 5secs later. Do you think I have a problem here? The heater is the M250S6DS-1NCZZ and id about 15 years old. Thanks in advance for any further info.
If the water heater seems to be heating and working normally then it may be fine, otherwise there may be a problem with the heating element as described.
@@AskTheElectrician people connect 240 volt water heaters to two legs of a 208 volt Wye all the time. What's the difference? It doesn't have to be line to line.
You can but as the elements are rated for 240 and your only supplying 208 your btu output of the heating elements will be in proportion to your decreased voltage. But that may be ok. Just raise the setting on the heating element thermostats, unless they are maxed out. The water will not heat up as hot, the elements won't get as hot, but you may be ok with that.
Hi. I need your expert assistance if you don't mind. I need to add a booster pump to my electric heater. I tap the power wiring from the heater wiring itself. Is this safe? What is the risk?
Typically a booster pump is wired from a separate electric circuit, and the booster pump is not wired to the water heater circuit. Keep in mind that most booster pumps in the USA are 120volt with small amperage, and our conventional domestic water heaters are 240volt 30amp. The concern is the booster pump requires less circuit power and the wiring is smaller, therefore we must provide over current protection for the booster pump, and we must provide the correct voltage. The only exception is when a water heater has a booster pump built into the main water heater unit and the internal wiring components provide the necessary circuit provisions and circuit protection. Be Safe and Be Careful.
Thanks a lot for the video, great explanation. My question is, do you think a 30 amp heater would work fine on a 100amp panel or i should upgrade to 200amps. Thanks in advance
You ought to be ok. The water heater isn't a continuous load. The longest the elements are on for a long time is on initial start up or if the water heater is completely drained if hot water, which can happen with a bathtub and Jacuzzi type tub.
Thank you sir for this great video. I'm gonna need to replace my gas water heater, I was thinking to go with a 40 gallon 240v. Now, do you think this electric tank it's gonna cost me more to run it vs the gas one?. Thank you very much. Ps the reason I'm replacing my gas heater is because I want to eliminate the chimney that runs in a mide of a bedroom on the second floor
Thanks for watching. As for the cost comparison, look for the yellow Energy tags on the water heaters which should provide the average cost based on energy consumption and average energy costs.
Im a Marine Engineer, Welder, Mechanic and I am making my brothers watch this so I don't have to do all the work myself lol Thanks And by the way this is the best video clip I have seen on this subject No need to go any further because even a dummy can understand this. Liked n' Subscribed, Cheers
Hi, very good video, and I have problems with my new Wareen heater, I put a new one electric water heater, all the conexión the same how was the old, y have power going to all the heating element , the ohm in the element are around 18, but the water still cold, I don’t know what could be the problem, if you can help me will be great, thank you 🙏 you
That would depend on the location and the electrical codes for the specific area, and this may be required for other countries. For Example: In California a disconnect is not required for a water heater. Otherwise if you would like to install a disconnect then you may do so by all means. Consider the following: A 30Amp Baseboard Heater does not require a disconnect switch as well, however they are both thermostatically controlled. Interesting, is it not.
@@AskTheElectrician In and of itself, the national electric code is not law. It's merely an advisory committee. The code, however, can be adopted as law by various states, counties, and municipalities.
Would a heat pump water heater require 10-3 for a neutral or does any water heater require a neutral maybe one with internet Wi-Fi connection or a hybrid unit
Typically a 240volt water heater does not require a neutral wire. Some smart controls that are installed for water heaters connect to a 120volt outlet.
Excellent and very informative video! Question: When installing a new water heater, is it necessary to check out the wiring of the elements? Thanks very much!
Thank you Jeff. The internal wiring of a new water heater from the factory should not need to be checked. The wiring and presets are typically reliable.
@@AskTheElectrician Thank you for the excellent video and your superb professional advice! Two more questions if you don't mind: Is it required to have a ground wire between the water lines on an electrical WH; and does the 10-2 have to be in metal at the connection? I'm running the wire along basement joists are only about 5' in a 100 year-old home. So from the rafter to the top of the WH is only about 2 1/2 feet. Thank you very much!
Application Specific: So if the described wires need replacing on your water heater then replace them with the same type and size wiring that your specific water heater has.
I've just had a new 60 gallon giant cascade water heater installed. But my water tank breaker keeps tripping. The specs say that the tank generates 40 amps and needs a 25-30 amp breaker, but I do have a 30 amp breaker. What could the problem be? Thanks
@@mathewwelsh9129 the solution was to replace the hot water tank circuit breaker with a new one at 30 Amps. Yes, circuit breakers do get old and break down. I've not had a single problem with the new circuit breaker. Note that I had an electrician change the breaker.
Obtain a 240volt Water Heater Time Clock for a standard electric water heater. The incoming 240volt circuit wires connect to the Line terminal screws, the Load wires connect to the water heater.
Hello! I have a bit of an issue. Yesterday I wanted to change a ceiling fan/light to a light fixture in my kitchen. I was unable to wire everything correctly and there was a short circuit - I went to the main fuse box and saw that the kitchen fuse was blown. I got a new fuse and replaced the broken one. Everything was working fine after that. After that I went to the basement and tried turning on the lights, they did not work nor did some of the outlets in the basement. So I went back to the main fuse box to check those fuses, taking each one out and putting a new one in to check if that was the issue. That didn’t work. The outlets are not GFCI so I don’t know if it’s the wires or something else. Any help would be immensely appreciated!
Sorry to hear about this problem John. You have stated that "I was unable to wire everything correctly and there was a short circuit" therefore attention should be given to correcting the initial wiring, because all of the issues you have described point back to the fact that something is definitely not wired correctly at the location of the original work - where the ceiling fan\light was located. Identifying the individual wires will be essential before one can make the correct wiring connections which will restore everything to the original functions.
I bought this water heater th-cam.com/users/postUgkx8G49mV71sAzUl9shXyLW-r3XgHH9EVh1 for use in my bus conversion. I installed it under my kitchen sink and it is fed by a high efficiency on-demand LP water heater. It is both a backup hot water source as well as a water saving device since we have hot water on demand rather than having to wait for the gas on demand water heater to finish its ignition cycle. I decided on this water heater due to the fact that it only draws 1300watts when it's ON instead of the 1500 watts that most Water heaters this size draw. In an RV a couple hundred watts can be a big deal. With very low standby losses, I don't have to worry about excessive power consumption. When propane is not available for our gas water heater, in conjunction with our low flow shower head there is enough hot water available to shower, albeit we won't be taking "hotel showers." Also very happy with the recovery rate of this water heater. Granted, it is quite small, but it does exactly what we need it to do.
Because the Water Heater Circuit is wired according to NEC Code: 310.16, Table 310-16, Utility room, panel, circuit, 30 Amp Breaker for water heater. Therefore a 30amp circuit requires a 10/2 w/Grd Type-NM Cable - in most installations. See more about Residential Home Electrical Codes: ask-the-electrician.com/electrical/electrical-code/electrical-code-search.php
Also in article 422.13 of the national electric code which states "The branch circuit over current device and conductors for fixed storage type water heaters that have a capacity of 450 L. (120 gallons) or less shall be sized not smaller than 125 percent of the rating of the water heater. So if your water heater is rated at 4500 watts at 240 volts, which is 18.75 amps, you then have to multiply 18.75x1.25=23.43 amps. Therefore you will need a minimum circuit rating of 25 amps with#10 AWG conductors.
Absolutely! Use bushings when installing flex that has sharp edges, however Some flex connectors do not require antishort bushings. The coupling may be made with approved materials and still provide the desired resullt. It should be noted that there are several ways of doing a job and still remain completely code compliant.
@@AskTheElectrician .....but you can in that code compliance, get cheap. I never will. There is code compliance, then safer code compliance. When we could burn down everything, I choose safer code compliance or I refuse the job. I never worry about the sharp edges, when I'm done none exist, by brushing or alternate method. Now go get the wire stretcher😃. Have a good one.
@@rhaastaa sounds like he doesnt want his job taken by having people know how to do this themselves rather than paying alot/getting ripped off to have a professional do it.
The wiring should be #10 AWG Copper for this 30amp circuit. Until the wiring has been upgraded it would be best to install a 20amp breaker to provide proper overload protection.
This is by far the best video I have reviewed for installing an electric water heater. Thanks.
Great to hear!
I have been plumbing 27 years and have installed many electric water heaters , my latest installl the water heater had a a dryer cord used for the power supply that plugged into the wall I wired the giant pigtail while waiting for the old water heater to drain which was full of calcium. I installed the new water heater and removed air from the the line by opening the tub valve. I switched on the power and had a short. The ground screw had pierced the dryer cord on the inside and caused the short but it took awhile to find this out. Lesson learned be wary of giant pigtails.
Yes indeed. Great find on your end, thank you for sharing this with us.
Yes thanks for sharing. Some years ago a cord and plug connection served as a means of disconnect if the breaker or fuse panel is not within sight of the unit, to protect someone repairing the water heater from being electrocuted if someone else turns the power on. Electric water heaters are not UL listed for cord and plug connection and I don't know that they ever were, nonetheless I have see it done a couple of times in homes 30 years old or more. Instead the unit should be hardwired with 10 guage copper wire connected to a disconnect safety switch or a double pole toggle switch rated for 30 amps near the unit if the breaker box is not within sight.
This is the best video I watched so far about water heater installation.
Thank You!
Really nice video with clear pictures and explanations, I can’t wait for another project so I can see another video as good as yours! Thank you
Thank you! I'm making more videos - so subscribe and tune in.
Great video, my water heater wiring looks like the one in the video, it's 4500w with 10awg on 30 amp . What I can't figure out is the wires that came in the unit that go to the two heating elements are 12 awg. How is that ok on a 30 amp breaker?
The circuit wires should be #10 copper for a typical 30amp water heater. You may consider upgrading the circuit. In the mean time the #12 wire should be on a 20amp breaker - something for you to consider.
@@AskTheElectrician Thanks for the reply. That's interesting that Rheem put 12awg wires in a unit intended to be on a 30 amp breaker.
@@AskTheElectricianBut that's not what he's really asking... He's asking why does the factory put 12/2 AWG wire coming out of the water heater's from the elements that's supposed to be wiring to 10/2 AWG 30 AMP 2 pole breaker? My new water heater is a AO Smith 40 gallon 30 AMP 2 pole breaker 240volts, and it also has 12/2 AWG wire coming from the unit? I do however have a question? My main panel is a 100 AMP panel box. It has a 12/2 AWG wired to a 30 AMP circuit feeding about 10 to 12 ft or less to a junction box, another piece of wire I can't tell if it's 12/2 AWG or 10/2 AWG running into a 4 circuit sub panel with only 2 circuits being used. A 20 AMP circuit and a 30 AMP circuit 2 pole breaker. The feeding Hot wire is wired to 1 lug, the Neutral to 1 lug and ground to bus bar. The 20 AMP circuit is wired to 2 receptacles that no longer works, it wired to Hot to circuit, neutral and ground to bus bar. Can I disconnect the 20 AMP circuit? And is a water heater supposed to be getting power this way? The old water heater was wired this way for more than 20 year's? I'd appreciate if you could help or give me some insight?
The water heater has 2 heating elements, 1 at top, 1 at bottom. Each element does not use 4500watts, however if both heating elements are on at the same time they together will draw 4500 watts (or less depending on the specific water heater and the factory settings for each heating element). So because each of these elements consume less watts they are wired with the smaller #12 wire.
First let me insert this here: The water heater has 2 heating elements, 1 at top, 1 at bottom. Each element does not use 4500watts, however if both heating elements are on at the same time they together will draw 4500 watts (or less depending on the specific water heater and the factory settings for each heating element). So because each of these elements consume less watts they are wired with the smaller #12 wire. Now as for your other question, no, typically a water heater circuit is a dedicated circuit which is installed from the panel directly to the water heater location. The circuit and sub panel you are referring to sounds very questionable and should be inspected to figure out just what is going on, and how or if it should be used. The wiring is in place, but it needs the purpose needs to be determined.
PS - Yes I do answer Questions here, even though this is for Comments, and that's OK, but remember that you can go to ask-the-electrician.com for a LOT more info, and asking a question there will bring you more resources.
My water heater was installed over a year ago cord gets really hot at the base when the hot water is used every time. It omits an order. Not sure if the installer connected correctly or a faulty cord, etc.
The electrical installation should be checked ASAP.
Have you contacted the installer about these concerns? You should.
Where do you get a 30 amp cord? Probably a dryer cord and plug.
finally a video with pics., and very clear explanations with wire gauge and all.!!!
Thanks Hector - Glad it was helpful!
@@AskTheElectrician very , thanks again
I have a 240V dual element 28 gal tank. I have a line coming into it coded Black /white/ground. There is a red & black wire from the tank.
Which color from the tank is connected to the black wire coming in, and the white wire coming in.
As noted in the video - when the incoming black and white are the 240volt wires, they connect to the black and red wires of the water heater, respectively.
In our old house, there is the disconnect box with fuses you talk about, I guess I can just remove it. The heater is right beside the break panel. The celling is not finished there (and it wont be) so I'm not sure how long should the metal wire conduit be. I guess about until were the drywall would be if the celling was done?
The circuit wiring should be protected by an approved conduit which is securely installed according to code. Be safe and enjoy your water heater.
when voltage testing this assembly at the top of the water heater, what should the readings be? i would expect 120v between black and ground, 120v between red and ground, and some random
small number like 10v between red and black.
are the red and black voltages then added in series, to get 240v, inside the water heater electrical panel?
The reading between the red and black wires on a typical 240 volt water heater circuit is 240volts.
Why do HWH typically use bare wire connections with wire nuts vs a screw terminal (similar to a breaker)?
Good question! Maybe because it would cost more?
@@AskTheElectricianthank you for taking the time to reply to my question. This baffles me especially if you follow the supplied wires in the junction box of the hot water heater down about 18” to where they screw down to a terminal at the upper element/thermostat. Seems as tho you could eliminate an extra splice by running the 10/2 right to the terminal.
The most convenient would be a nice terminal block in the upper built-in compartment of the water heater, but like you said… it would add a little extra cost. Personally… I would find it well worth the money.
@@AskTheElectrician I asked a buddy of mine that is an E 1 and his only explanation was the cost factor as well.
My current hot water tank is not grounded, and there’s not available wire to ground it. It was already in a house that I bought. I’m replacing the hot water tank today, and I’m wondering if i need to ground the new one, or not?
Just to verify if I have a black and a white wire plus ground do I use my white as a power conductor and that would be fastenened on the one breaker screw?And it doesn't matter which one ,right?
In the USA, for a typical 240volt 30amp water heater circuit in an older home, where the wires are black, white and a bare copper or a green ground wire, in many installations the white wire was used as a power wire and attached to one terminal of the 2pole circuit breaker, and the black wire on the other terminal of the 2pole circuit breaker, and no - it does not matter which position these wires are in as attached to the 2pole circuit breaker. It is always best to identify the white wire as a power conductor using red electrical tape at the circuit breaker and at the water heater. Make sure to verify the circuit wiring as described.
Ok I have a white black and bare copper wire for ground from breaker and red black and green wires on water heater the black is hot on the house wire and white is neutral or negative and which wire red or black is negative or positive on the water heater because ground is green for sure trying to find out if the black on the water heater is the negative or the hot because the black on the house is hot so it would be backwards can't find a picture or anyone stating this definitive statement?
question concerning wiring.? My electrical panel has a 30 amp breaker attached to a 10/3 wire which goes to the water heater space, but the water heater an AO Smith 100 only has 2 wires from it a red wire and a black wire. plus ground of course ,but my question is do I at the water heater tie wiring black to black and white to red or red to red and black to black then using a wire nut to cap off the white wire?
Typically when there is a 10/3 with ground to a water heater the white wire is not used, therefore it is capped off, then all the connections are color to color. It is best to verify the wiring to make sure the black and red wires are in fact the power wires, as they should be.
Thanks for the video. I know this may be a code question so mileage might vary. Running the wire from the ceiling to the tank, or alternately, from a junction box to the tank, does it have to be shielded with the metal tubing as you've shown or can we just run the wire as is, with plastic sheathing still on, right to the tank?
The wire should be protected using an approved method, typically metal flex and connectors.
@@AskTheElectrician I'm going to use a liquid tight flexible plastic sheath, used for outdoor applications usually. I just don't like the idea of a metal sheathing for electricity.
@@AskTheElectricianA video by a self described inspector stated that BX is not appropriate. Is there another flexible metal jacketed type of product? I’ve seen a few websites that don’t offer much help in differentiating.
Just wanted to say nice info on the water heater video. Just a question now for you, I'm in going to install a new water heater in our mobile home but the wire is 12 gauge and to short. New heater is taller than the old one. Whats the best way to rewire this with 10 gauge?
Thank you, glad the video was helpful.
Double check the electrical circuit specifications on the new water heater to make sure it requires a 30amp circuit, only because not all water heaters are alike, and some for mobile homes may be small - so check this.
If a new circuit is required then a new cable may be required to be installed from the water heater to the electrical panel, all according to code. If the existing water heater circuit will not be used then it may be disconnected and removed, and the new circuit breaker could take it's place. The qualified installer will need to be aware of all applicable codes that apply to the project.
ok thank you and I'll double check it but I did see that it requires 10 ga. and the breaker has a double pole 20 amp in it.
I want to install a new electric water heater and remove the gas water heater, however the gas furnace piping is attached.
I'm hoping to place the new electric water heater in the garage.
How much would a job like that run of adding new wiring, relocating pipes from the inside wall to the interior of the garage cost? And would the mechanic need a permit from the city?
The cost would depend on where you are located, the cost of the materials, and the current labor charges for your area. Get at least two bids from local licensed contractors who have excellent references.
can you explain wire black and white run to my water heater tank,are they 240 v ? breaker circuit show 30A
Can I do a direct run from my service panel thru the attic down the ceiling to my water heater about 40 ft
That is one option, of course all being done according to NEC Codes.
I understand should be three wires two hot with ground..in this house we have red black green and white.
So, please how to wire that white wire?
I know red to red // black to black// green to ground .that that white wire tie together with red or what ?
Thank you,
Cap off the white wire as it is not needed for a conventional 240volt electric water heater.
What do you do when have 8 gauge aluminum wire going to the water heater that has 10 gauge copper whip. I'm thinking Polaris 2 port 4-14awg insulated tap connector. They are rated for Aluminum and copper. I had a plumber wire mine in with wire nuts burned the wire up into the wall I was extremely lucky the strain relief forced it to pull enough current to trip the 30 amp breaker before it got into my attic would have burned my house down. I had the electrician install a disconnect at the water heater this was several years ago before I knew about those Polaris connectors. He wanted to use those purple wire nuts I told him he was crazy never allow wire nuts again with AL and CO wire. The disconnect uses lugs and is rated for AL and CO he agreed to that. My understanding that even though branch aluminum wire has been banned still used for home runs like stoves, water heaters, and dryers. My 1970's house has AL branch wire I'm in the process of pig tailing using alummicons busbars are UL listed for AL and copper very good products well worth the money. Once I pigtail replace every switch and recep put the alumicons in going to replace my breakers with Arcfault gfci breakers I will be able to sleep at night knowing the AL wire is safe in my house.
Wow wow wow,.Señor Dave Rongay..what an excelente video.,looking for info on how to install my Water heater never expected to find such a jewel of info ..Muchas Gracias ,Señor.
You made me a happy man today
Thanks Roberto, I'm glad it was helpful for you!
Hi, great video. Follow up Qs, Should all the wires after the feed lines 1 & 2 are #10 ga should all the other wires from Tstats to elements be #10 as well? I seem to remember #12 ga being used over the years but not sure that is correct? This hwh was wired right except for the black wire from the lower Tstat was on the upper Tstat left side bottom screw and the upper element had its wire on the upper Tstat right side bottom screw. So, they were reversed and that would seem to cause the lower element to come on, but the top I don't think it would ever come on? What is your opinion?
The internal wiring of a typical water heater is factory wired, therefore the installer only has to be concerned with the main circuit connections. The only time we would need to access the other areas is if the water heater element, or one of the controls becomes faulty and needs to be replaced. But you are correct, some of the internal wiring is not #10 because there are two elements that do not pull 30amps each. Great questions - Thanks for viewing the video and sharing your thoughts.
It's not so much the size of the wire that determines how many amps can flow as the temperature rating of the insulation. That's why the wires in the unit are smaller than the supply wires. You can get some really high temp insulation, like asbestos cloth like is used in ovens.
Hello, so I'm in the process of replacing my sister's old 2008 water heater that just started leaking this weekend. As I was inspecting the whole area around the water heater, I noticed the electrical wiring (with romex) for the water heater, was coming out of the floor (just a hole drilled through the wood flooring with no grommet) and free floating up and over to the top of the existing water heater. Would using flex and then securing that along the closest wall be a good way of protecting the wire?
Yes it will, the wiring should be protected and not exposed such as it is, great for you to improve this condition and make it right.
@@AskTheElectrician hello, I have the same situation in my house. My question is if we are allowed to run the romex through the conduit as is or do we have to strip the outer jacket once it transitions to flex conduit?
Is it normal for the water heater to have 12 gague wires that hook up to 10 gauge power wires? I'm stuck at this step, I'm switching from a gas water heater and using a former ac power line that is 10-2 wire from a dual 30 Amp breaker. It feels strange to me that the water heater has 12 gauge wire to meet my 10 gauge. Is this normal?
#10 gauge wire should be used for a 30amp circuit.
If there is are two green ground screws (one inside the compartment like your example and one on the top cover plate) does it make any difference which ground screw you use?
You could loop the ground wire thorough each ground screw, and make sure the ground wire is connected to the ground screw inside the junction area.
Should there be a disconnect on the wall near the water heater?
Personally I think there should be, however since a typical water heater is a permanent installation with (almost) no parts to service, up to now the NEC does not require a disconnect. Note that the newer hybrid water heaters may require a disconnect.
Water and rust is in the wires cover box. Cover lid is rusted. Water came up through hole. Can this be cleaned up? Its a 2010 Ao Smith electric? Did water come up because its all rusted or just that?
The water heater should be checked to make sure there are no water leaks. It may be that there was a water leak in the past, possibly one of the water pipe fittings above the unit. You may consider turning off the circuit power and cleaning the area and removing the rust to make sure the unit is kept in good condition.
How about a lockable disconnect close to the hot water tank. Is that required. ?
Personally I think a disconnect is a great idea, however since a typical water heater is a permanent installation with (almost) no parts to service, up to now the NEC does not require a disconnect.
I have an old wire coming out of the breaker box.
Black and white are hooked on the top screw of the
Breaker.. the red wire hooked on the bottom of the breaker.
Where does the red wire hook too in the hot water heater?
When in doubt I test the wires to verify the voltage, then connect to the wires at the water heater as described in the video.
Where you go from the conduit to the BX what kind of connector is that? I have never seen one like that.
It is an EMT to Flex Conduit adapter.
Well done video young man! I shared it with my brother who was looking for help with his project
Thanks again DLT - and Thanks for sharing the info with others. Come on by the website sometime for more goodies.
Question my husband and I was putting our new electric water in and when we removed pipe all of the water was not drained so it leaked overt the electric plate with the neutral ground cords . Now we did blow dry it but should we still water a day before restarting electricity
if all of the electrical components are now dry then it should be ok.
What about older pre 1994 homes with a 10-30R and no ground? My plumber used the neutral and I’ve bern wondering if that is ok.
For the older homes, if the cable has Black, Red, and White insulated wires that are fed directly from the main electrical panel, and the White wire is bonded to the grounded terminal bar then using the White wire as the ground wire is OK, but the white wire should be marked with green tape or a green marker at each location.
My 40 gallon hotwater heater on 2 25amp breaker. is this right? I bought the manufactured new home 2022
You could check the specification label to see what size circuit is required, but if your water heater has been working fine as it is, then there is no need to change it.
If it needs 30 amps your really tight. Hopefully the elements won't draw too much.
Hello. I have power at the new element, but can't hear it working. Thoughts?
The element may be faulty. If this is a new water heater double check to make sure the water is turned on, and bleed out trapped air by running water to other areas of the home.
Great video and highly informative. I reviewed my BradfordWhite service manual which says the following in regards to diagnosing the heating ellement: "Reading should be 12.8 ohms (±6%) for a 240volt, 4500 watt element. A reading outside the range using the formula above (±6%), indicates a bad element and the element must be replaced." So I checked both upper and lower elements and my multimeter shows 12-13ohms initially and as I held the multimeter on the contacts the reading dropped to 9.5ohms after 4-5secs. Im not sure whether to go by the initial 12-13ohm reading or the 9.5ohm reading 5secs later. Do you think I have a problem here? The heater is the M250S6DS-1NCZZ and id about 15 years old. Thanks in advance for any further info.
If the water heater seems to be heating and working normally then it may be fine, otherwise there may be a problem with the heating element as described.
Can you connect a 240 volt water heater to a 208 volt high leg via a straight rated 30 amp circuit breaker or fuse?
Not unless the water heater manufacturer states that you can.
You mean you can do that unless it's in violation of its UL listing?
Be sure to check with the manufacturer - that way you will be sure it is under warranty as well.
@@AskTheElectrician people connect 240 volt water heaters to two legs of a 208 volt Wye all the time. What's the difference? It doesn't have to be line to line.
You can but as the elements are rated for 240 and your only supplying 208 your btu output of the heating elements will be in proportion to your decreased voltage. But that may be ok. Just raise the setting on the heating element thermostats, unless they are maxed out. The water will not heat up as hot, the elements won't get as hot, but you may be ok with that.
Hi. I need your expert assistance if you don't mind. I need to add a booster pump to my electric heater. I tap the power wiring from the heater wiring itself. Is this safe? What is the risk?
Typically a booster pump is wired from a separate electric circuit, and the booster pump is not wired to the water heater circuit. Keep in mind that most booster pumps in the USA are 120volt with small amperage, and our conventional domestic water heaters are 240volt 30amp. The concern is the booster pump requires less circuit power and the wiring is smaller, therefore we must provide over current protection for the booster pump, and we must provide the correct voltage.
The only exception is when a water heater has a booster pump built into the main water heater unit and the internal wiring components provide the necessary circuit provisions and circuit protection.
Be Safe and Be Careful.
@@AskTheElectrician Thank you for your kind response. Appreciate it.
Thanks a lot for the video, great explanation.
My question is, do you think a 30 amp heater would work fine on a 100amp panel or i should upgrade to 200amps.
Thanks in advance
It all depends on the existing electrical load that is now on the panel, and what size the existing panel is.
Thanks for watching and great comment.
You ought to be ok. The water heater isn't a continuous load. The longest the elements are on for a long time is on initial start up or if the water heater is completely drained if hot water, which can happen with a bathtub and Jacuzzi type tub.
Thank you sir for this great video. I'm gonna need to replace my gas water heater, I was thinking to go with a 40 gallon 240v. Now, do you think this electric tank it's gonna cost me more to run it vs the gas one?. Thank you very much. Ps the reason I'm replacing my gas heater is because I want to eliminate the chimney that runs in a mide of a bedroom on the second floor
Thanks for watching. As for the cost comparison, look for the yellow Energy tags on the water heaters which should provide the average cost based on energy consumption and average energy costs.
Oh ok, I'll check that out. Thanks for your response
Im a Marine Engineer, Welder, Mechanic and I am making my brothers watch this so I don't have to do all the work myself lol Thanks And by the way this is the best video clip I have seen on this subject No need to go any further because even a dummy can understand this. Liked n' Subscribed, Cheers
Thank You JB,
Have fun working with your brothers on your projects!
Is it okay to use 5500 watt when it says 4500 watt on the water heater for a heating element?? Need to know asap please?
The replacement water heater element should be the same as the original heating element.
mine seems to have to hot ( faze,power) wire coming to the system no neutral nor ground wire .what should I do
The typical approved circuit for a residential conventional electric hot water heater is a 30mp 240volt circuit which includes ground wire.
Hi, very good video, and I have problems with my new Wareen heater, I put a new one electric water heater, all the conexión the same how was the old, y have power going to all the heating element , the ohm in the element are around 18, but the water still cold, I don’t know what could be the problem, if you can help me will be great, thank you 🙏 you
You also need a disconnect at the location of the water heater if it is not in line of sight from the breaker that controls it.
That would depend on the location and the electrical codes for the specific area, and this may be required for other countries.
For Example:
In California a disconnect is not required for a water heater.
Otherwise if you would like to install a disconnect then you may do so by all means.
Consider the following:
A 30Amp Baseboard Heater does not require a disconnect switch as well, however they are both thermostatically controlled.
Interesting, is it not.
@@AskTheElectrician In and of itself, the national electric code is not law. It's merely an advisory committee. The code, however, can be adopted as law by various states, counties, and municipalities.
Some TH-cam videos state that a breaker lockout device is acceptable instead of a local shutoff.
Would a heat pump water heater require 10-3 for a neutral or does any water heater require a neutral maybe one with internet Wi-Fi connection or a hybrid unit
Typically a 240volt water heater does not require a neutral wire. Some smart controls that are installed for water heaters connect to a 120volt outlet.
Excellent and very informative video! Question: When installing a new water heater, is it necessary to check out the wiring of the elements? Thanks very much!
Thank you Jeff. The internal wiring of a new water heater from the factory should not need to be checked. The wiring and presets are typically reliable.
@@AskTheElectrician Thank you for the excellent video and your superb professional advice! Two more questions if you don't mind: Is it required to have a ground wire between the water lines on an electrical WH; and does the 10-2 have to be in metal at the connection? I'm running the wire along basement joists are only about 5' in a 100 year-old home. So from the rafter to the top of the WH is only about 2 1/2 feet. Thank you very much!
What size are the wires from the thermostat to the element? Yellow, blue etc.
Application Specific: So if the described wires need replacing on your water heater then replace them with the same type and size wiring that your specific water heater has.
14awg
Excellent! Concise and clear. Thanks!
Thanks So Much Les, Glad it was helpful!
Can you help me with reconnecting humidifier wires to a new water heater with a solar system set up
I've just had a new 60 gallon giant cascade water heater installed. But
my water tank breaker keeps tripping. The specs say that the tank
generates 40 amps and needs a 25-30 amp breaker, but I do have a 30 amp
breaker. What could the problem be? Thanks
I'm about to install the same model water heater, so i'd like to know the answer here before I do! I want to make sure I get the correct breaker.
@@mathewwelsh9129 the solution was to replace the hot water tank circuit breaker with a new one at 30 Amps. Yes, circuit breakers do get old and break down. I've not had a single problem with the new circuit breaker. Note that I had an electrician change the breaker.
@@lduranceau8046 thanks for the follow up info!
Great! Thanks for the feedback!
The only wire I can find locally is 10/2 Type NM-B. Does a "B" make a difference?
The 10/2 NM-B Cable is designed for indoor residential use and should work fine.
@@AskTheElectrician so th4
How do you wire a water heater timer?
Obtain a 240volt Water Heater Time Clock for a standard electric water heater. The incoming 240volt circuit wires connect to the Line terminal screws, the Load wires connect to the water heater.
We appreciate all the info - thank you!
Any time!
@@AskTheElectrician @ how much labor cost??
Just installed a new water heater and only getting lukewarm. I have it turned to 125 degrees it’s been 8 hours
Make sure the circuit voltage is correct.
so there is no neutral connection on electric hot water heaters????
A neutral wire is not required for a typical 40gallon 240volt electric water heater.
That is very thorough thank you
Glad you enjoyed it!
WOW… We have one that looks similar to, but Older than That glass fuse panel. 1:45 😮
Yes there are still a lot of them being used out there.
How much would this labor cost??
Time and materials - relevant to the project and the location.
Thank you very much 😀
You're Welcome Fernando 😊
Hello! I have a bit of an issue. Yesterday I wanted to change a ceiling fan/light to a light fixture in my kitchen.
I was unable to wire everything correctly and there was a short circuit - I went to the main fuse box and saw that the kitchen fuse was blown. I got a new fuse and replaced the broken one. Everything was working fine after that.
After that I went to the basement and tried turning on the lights, they did not work nor did some of the outlets in the basement. So I went back to the main fuse box to check those fuses, taking each one out and putting a new one in to check if that was the issue. That didn’t work.
The outlets are not GFCI so I don’t know if it’s the wires or something else. Any help would be immensely appreciated!
Sorry to hear about this problem John. You have stated that "I was unable to wire everything correctly and there was a short circuit" therefore attention should be given to correcting the initial wiring, because all of the issues you have described point back to the fact that something is definitely not wired correctly at the location of the original work - where the ceiling fan\light was located. Identifying the individual wires will be essential before one can make the correct wiring connections which will restore everything to the original functions.
You got a mess. Hire the guy.
Best explained video thank you
You're welcome!
Why does it not require a neutral?
Because that is the way a 240volt device works, and it is much more efficient compared to 120volt devices.
There are no 120 volt loads on the water heater itself. Thus you need only the 2 hots and the equipment grounding conductor.
Good job budd 😊
Thanks 😁
very detail love it!
Thank you!
I bought this water heater th-cam.com/users/postUgkx8G49mV71sAzUl9shXyLW-r3XgHH9EVh1 for use in my bus conversion. I installed it under my kitchen sink and it is fed by a high efficiency on-demand LP water heater. It is both a backup hot water source as well as a water saving device since we have hot water on demand rather than having to wait for the gas on demand water heater to finish its ignition cycle. I decided on this water heater due to the fact that it only draws 1300watts when it's ON instead of the 1500 watts that most Water heaters this size draw. In an RV a couple hundred watts can be a big deal. With very low standby losses, I don't have to worry about excessive power consumption. When propane is not available for our gas water heater, in conjunction with our low flow shower head there is enough hot water available to shower, albeit we won't be taking "hotel showers." Also very happy with the recovery rate of this water heater. Granted, it is quite small, but it does exactly what we need it to do.
Great job teach
Thank you!
if its 4500W why can't you use a 20" breaker with 12/2 wire, that would be 240x20=4800W
Because the Water Heater Circuit is wired according to NEC Code: 310.16, Table 310-16, Utility room, panel, circuit, 30 Amp Breaker for water heater.
Therefore a 30amp circuit requires a 10/2 w/Grd Type-NM Cable - in most installations.
See more about Residential Home Electrical Codes:
ask-the-electrician.com/electrical/electrical-code/electrical-code-search.php
Also in article 422.13 of the national electric code which states "The branch circuit over current device and conductors for fixed storage type water heaters that have a capacity of 450 L. (120 gallons) or less shall be sized not smaller than 125 percent of the rating of the water heater. So if your water heater is rated at 4500 watts at 240 volts, which is 18.75 amps, you then have to multiply 18.75x1.25=23.43 amps. Therefore you will need a minimum circuit rating of 25 amps with#10 AWG conductors.
Great Job Nicely Done ⚡️👍🏼
Thank You Bigmo!
Wiring seems to be correct but still no hot water
Check to make sure the water is turned on, and the circuit breaker is turned on.
thank you sir
Your Most Welcome Aaron!
All i saw was code violations as an electrician. Antishort bushings, correct couplings anyone?
Absolutely! Use bushings when installing flex that has sharp edges, however Some flex connectors do not require antishort bushings. The coupling may be made with approved materials and still provide the desired resullt.
It should be noted that there are several ways of doing a job and still remain completely code compliant.
@@AskTheElectrician .....but you can in that code compliance, get cheap. I never will. There is code compliance, then safer code compliance. When we could burn down everything, I choose safer code compliance or I refuse the job. I never worry about the sharp edges, when I'm done none exist, by brushing or alternate method. Now go get the wire stretcher😃. Have a good one.
Chad is synonymous with Karen
@@rhaastaa lol.....so noting correct protocol for not having a fire is being a karen.....got it. Imagine thinking that was an insult.
@@rhaastaa sounds like he doesnt want his job taken by having people know how to do this themselves rather than paying alot/getting ripped off to have a professional do it.
I need water hookup not electricity
Then type that in, this video specifically says wiring.
PICTURE SAYS AO SMITH ASSEMBLED MADE IN MEXICO !!!!!! CHEAP !!!!!!
Interesting - but most of them are made there!
:)
My hot water heater has 12 awg wire. But my breaker is 30 amp with 10/2 wire. Is it safe to connect the 12 awg with the 10/2 wire?
The wiring should be #10 AWG Copper for this 30amp circuit. Until the wiring has been upgraded it would be best to install a 20amp breaker to provide proper overload protection.
Run #10 all the way from panel to connections on water heater and use a 2 pole 30a breaker at panel.
Thank you sir
Your Welcome!