This video was produced by the Northern Mid-Atlantic Solar Education and Resource Center, part of The Pennsylvania State University. You can learn more at www.solarcenter.psu.edu
One important point that is not mentioned is that the ground rod will only cause a ground fault if it's impedence is lower the about 8 ohms. 120v divided by 15 amps. Most grounds don't meet that requirement. The ground is only there to sink residual voltages and of course a lightening strike. It's your neutral that returns the current to your source and your ground should be bonded to the return path for it to trip your breaker.
What about grounding solar and INV via the copper water pipes which are naturally grounded as they run underground...this in combination to the main and critical load panel which are grounded via a 8 feet copper bar ?
Is the first diagram showing th3 PV ground rod connected all the way to the house AC ground rod? Is it not best to Isolate the DC and AC grounds so as not to create a loop?
NEC 2017 Code has put a bit of a cloud on this video "Functionally Grounded" versus "Solidly Grounded" and then 690.41(A)(1)-(6) - What type of system do you have and where does theCode send you. SGE, SEC, EGC, etc. - Probably in a "do loop".
You rarely see solidly grounded PV systems. The AC grid may be solidly grounded, but the DC side is rarely (if ever) solidly grounded. Systems that ground one of the polarities, used a ground fault fuse or breaker to ground the grounded conductor, which the NEC now calls functionally grounded systems. Systems that ground neither of the polarities, are "functionally grounded" by being connected to a grounded AC system through a non-isolated inverter, and will be constrained to be at equal and opposite voltages to ground. I like the term functionally grounded, but I dislike the fact that it applies to two completely different kinds of systems. I'd prefer "functionally grounded" to apply to the grounded systems that ground one polarity through GFCI, and "symmetry grounded" to be the term for the non-isolated inverter systems.
Yes I do have a thunder arrestor on my roof and the inverter has its own ground terminal. My grounding is such that the ground wire that comes from the cc goes into the inverter then to the the ground yet this still happens, my inverter still shuts off and shows short circuit during lightening/thunderstorm My thought is whether it is not proper to wire the cc and inverter together in the same system, or if they have be the cc and inverter should have separate grounding independent of each other or maybe the ts mppt grounding serves for both equipment. NOTE. My controller is a Morningstar ts-mppt 45amp. How did you wire your system and what is the proper way to ground one's system.
if you have a un-grounded system ,, both positive and negative are isolated from ground ,, then grounding your metal towers , metal cases on equipment etc is only good for conducting lightening to ground // in any ungrounded system the current has no desire to go to ground
Plastics compress with mounting hardware. Aluminum frames may be superior to plastics in expansion, extreme temperatures, cracking and ability to handle heavy snowfalls.
urgentcareguy3 -- WEEB stands for Washer, Electrical Equipment Bond, and is specifically produced by Wiley Electric. Other bonding washers might be made by other companies, and not all bonding washers are made by Wiley Electric. My answer, in this case, is specifically directed at WEEBs, though, and might not be true for all products. The short answer is it's not all four, OR just one -- it's probably two, as a minimum. The long answer, in the case of WEEBs, is that either the racking manufacturer or Wiley will give you some documentation that explains the proper way to use their equipment. When a piece of electrical equipment goes through the necessary testing to be legal for use in the United States (see Wiley's UL and ETL certification documents on their website, for instance), the test is done with their equipment AND the instructions for using that equipment, and in order not to maintain code compliance, you must install that equipment per the manufacturer's directions. For an example, you can check out page 9 of Wiley's installation instructions for Unirac's SolarMount racking system (this page is essentially replicated in Unirac's installation manual for their product) which shows different ways to install the washers (shown by Xs) based on whether you have an odd or even number of modules. www.we-llc.com/docs/librariesprovider3/Weeb-catalog/104-0404-000010-015.pdf?sfvrsn=0 As you can see, no module has fewer than 2 WEEBS, but one does have all four corners used. The rest of the manual covers all of the other details about the product, if you're curious.
I would say if you can conveniently install a seperate ground it would be preferred not to mention safer, however depending on your install (and local code requirement) attaching to the AC ground rod is allowed.
@@noneya3504 I would disagree. It is better if you have a common grounding electrode system for everything on the premises. Otherwise, you might pick up ground voltage gradients, which manifest as current on the EGC system, where it doesn't belong. This is the issue with 690.47(D)anger, that has now been removed from the code.
i've got an array with mixed m-250's, and m250's. I'm running the dc wirign inside the house, with the inverters and trunk cables inside, instead of out. i'm having intermittent trouble with one of the 250's, flashing red instead of yellow... checked 40v at pv panel, and short circuit amperage over 6 amps. reset, and still has problem sometimes. I do have a ground cable connecting the steel structure to all of the inverter chassis, as if they were connected. any ideas what could be wrong?
![Solar Photovoltaic (PV) Systems, Grounding Electrode System, NEC 2020 - [690.47], (9min:30sec)](http://i.ytimg.com/vi/cZo8ict33_I/mqdefault.jpg)
This video needs updating as 2 separate ground rods cause a difference of potential that is dangerous and further updated in the new NEC book
One important point that is not mentioned is that the ground rod will only cause a ground fault if it's impedence is lower the about 8 ohms. 120v divided by 15 amps. Most grounds don't meet that requirement. The ground is only there to sink residual voltages and of course a lightening strike. It's your neutral that returns the current to your source and your ground should be bonded to the return path for it to trip your breaker.
this is going into the SAVED videos. it answered so many questions .
Very informative, useful, and well made. Wish there were more videos like this.
The presentation is straightforward on point, very good
thanks for this very thorough and well presented video. please upload some more
Great presentation. Makes complete sense to separate array from charge/inverter.
I believe I have now found a way to properly ground a dual-axis solar tracker. Thank-you for your efforts.
Excellent! Thank you.
Excellent presentation., Thanks
is there a PV inspection checklist A through Z that exists? residential and Commercial
In the solar production meter the center lugs is it always the ground that gets hooked and neutral passes through?
What about grounding solar and INV via the copper water pipes which are naturally grounded as they run underground...this in combination to the main and critical load panel which are grounded via a 8 feet copper bar ?
Thanks, ...
COOP
the WiSeNhEiMeR from Richmond, INDIANA
...
Is the first diagram showing th3 PV ground rod connected all the way to the house AC ground rod? Is it not best to Isolate the DC and AC grounds so as not to create a loop?
inverter is far away from the panels so I have 1 rod near the panels and another the regular at home, I think this is ok, what do you think
I always thought you could get galvanic corrosion between aluminium and stainless steel? Would this not happen with the WEEB stainless steel washer?
Thank you. 🙂
NEC 2017 Code has put a bit of a cloud on this video "Functionally Grounded" versus "Solidly Grounded" and then 690.41(A)(1)-(6) - What type of system do you have and where does theCode send you. SGE, SEC, EGC, etc. - Probably in a "do loop".
You rarely see solidly grounded PV systems. The AC grid may be solidly grounded, but the DC side is rarely (if ever) solidly grounded. Systems that ground one of the polarities, used a ground fault fuse or breaker to ground the grounded conductor, which the NEC now calls functionally grounded systems. Systems that ground neither of the polarities, are "functionally grounded" by being connected to a grounded AC system through a non-isolated inverter, and will be constrained to be at equal and opposite voltages to ground.
I like the term functionally grounded, but I dislike the fact that it applies to two completely different kinds of systems. I'd prefer "functionally grounded" to apply to the grounded systems that ground one polarity through GFCI, and "symmetry grounded" to be the term for the non-isolated inverter systems.
Good resource
How can I ground the solar array in RV with IT system? (isometer)
Yes I do have a thunder arrestor on my roof and the inverter has its own ground terminal. My grounding is such that the ground wire that comes from the cc goes into the inverter then to the the ground yet this still happens, my inverter still shuts off and shows short circuit during lightening/thunderstorm My thought is whether it is not proper to wire the cc and inverter together in the same system, or if they have be the cc and inverter should have separate grounding independent of each other or maybe the ts mppt grounding serves for both equipment. NOTE. My controller is a Morningstar ts-mppt 45amp. How did you wire your system and what is the proper way to ground one's system.
Maybe put a seceond arrest or for your inverter. I hear you need to do that for both the panels and the inverter.
Does nearby lightning have an effect even if its not contacting your setup?
there are directs strikes, and indirect effects from "nearby" strikes@@mickwolf1077
if you have a un-grounded system ,, both positive and negative are isolated from ground ,, then grounding your metal towers , metal cases on equipment etc is only good for conducting lightening to ground // in any ungrounded system the current has no desire to go to ground
Plastics compress with mounting hardware. Aluminum frames may be superior to plastics in expansion, extreme temperatures, cracking and ability to handle heavy snowfalls.
Are the WEEBs used at all 4 bolts of a PV panel, or just one bolt ?
urgentcareguy3 -- WEEB stands for Washer, Electrical Equipment Bond, and is specifically produced by Wiley Electric. Other bonding washers might be made by other companies, and not all bonding washers are made by Wiley Electric.
My answer, in this case, is specifically directed at WEEBs, though, and might not be true for all products.
The short answer is it's not all four, OR just one -- it's probably two, as a minimum.
The long answer, in the case of WEEBs, is that either the racking manufacturer or Wiley will give you some documentation that explains the proper way to use their equipment.
When a piece of electrical equipment goes through the necessary testing to be legal for use in the United States (see Wiley's UL and ETL certification documents on their website, for instance), the test is done with their equipment AND the instructions for using that equipment, and in order not to maintain code compliance, you must install that equipment per the manufacturer's directions.
For an example, you can check out page 9 of Wiley's installation instructions for Unirac's SolarMount racking system (this page is essentially replicated in Unirac's installation manual for their product) which shows different ways to install the washers (shown by Xs) based on whether you have an odd or even number of modules. www.we-llc.com/docs/librariesprovider3/Weeb-catalog/104-0404-000010-015.pdf?sfvrsn=0 As you can see, no module has fewer than 2 WEEBS, but one does have all four corners used. The rest of the manual covers all of the other details about the product, if you're curious.
Thank you for the very thorough reply! Guess it is time for some research.
If my panels are about 120 foot from the charger is the same principle
can i ground all the AC and DC equipment on the same earth grounding rod? or do they need to be grounded apart?
REPLY
I would say if you can conveniently install a seperate ground it would be preferred not to mention safer, however depending on your install (and local code requirement) attaching to the AC ground rod is allowed.
@@noneya3504 I would disagree. It is better if you have a common grounding electrode system for everything on the premises. Otherwise, you might pick up ground voltage gradients, which manifest as current on the EGC system, where it doesn't belong. This is the issue with 690.47(D)anger, that has now been removed from the code.
i've got an array with mixed m-250's, and m250's. I'm running the dc wirign inside the house, with the inverters and trunk cables inside, instead of out. i'm having intermittent trouble with one of the 250's, flashing red instead of yellow... checked 40v at pv panel, and short circuit amperage over 6 amps. reset, and still has problem sometimes. I do have a ground cable connecting the steel structure to all of the inverter chassis, as if they were connected. any ideas what could be wrong?
Isolate your neutrals.
So how does that apply to a ship?
still not clear if DC and AC ground can be on same earth rod?
Per the video it is possible to be used on the same earth ground rod, but check with your local and or inspector if it is permitted in your area
3:26 the circuit breaker does not open. 120Volts/25ohms= 4,8amps. This is not going to trip the circuit breaker.
I like the part showing Obama touching the solar panel, suggest it shouldn't be grounded. well, what will happen?
0:32 Your video is a bit early for Trump, he would be hugging the solar panels instead.
0:31 - LMFAO
hhahahaha . Very appropriate photo