Interconnected Electrical Power Production Sources, Supply-Side Source Connections,NEC 2020 [705.11]
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- เผยแพร่เมื่อ 2 ต.ค. 2022
- When interconnected electrical power production sources, such as wind powered generators, solar PV systems, or fuel cells are connected in parallel with utility power, special considerations for safety and efficiency must be made. This makes supply-side source connections a most critical aspect of a safe and compliant installation. This video on Section 705.11 explains just what the requirements are to accomplish this.
This video is an extract from Mike Holt’s Understanding 2020 NEC Requirements for Solar PV and Energy Storage Systems. For more information about this product visit www.MikeHolt.com/Solar or call 888.632.2633.
For over 40 years, Mike Holt Enterprises has been providing quality electrical code training to help electrical professionals learn the Code, prepare for exams, and improve their electrical knowledge. Visit www.MikeHolt.com for exam preparation tips and training, instructor and curriculum support, continuing education options, free videos and graphics, and so much more.
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Thank you so much for hosting this panel of experts. It's really helpful to discuss these utility specific guidelines.
I work with Xcel here in Minnesota, and would love if they would just make a set of industry standard templates for interconnection. I'm willing to supply the meter sockets that they want to work with----just tell me *exactly* which ones to buy that would make their lives easier.
You are the Best Sir. I have been following u for 23 years, and still i learn new things every Nec Cicle. God bless you sir. Stop Riding Bike. Lol
Thanks again Mike Holt.
Mike and at el,
In my opinion, change in definition of service is just to clarify PV System is a parallel source of energy, called service. Yours interpretation abiut ground wire requirement is correct, we don't need to bond conduit if it is not metallic.
However, electrical safety point of view, shouldn't PV system be grounded? If so why we ground that with separately derived grounding grounding? If utility company permit to run ground wire through metering panel, we should bring ground wire all the way to service disconnect switch where we are bonding neutral and ground wire. This is just my opinion.
Thanks team! This answered a topic I was researching.
Line side taps right before the service disconnect are the more common way of connecting to the supply side.
I recently worked with an inspector, and his position was that the inverter AC disconnect is in fact a service disconnecting means.
Inverter equipment does draw power from the service conductors then it is in standby, and the PV AC disconnect interrupts that, so by the definitions I would also conclude that it is a service disconnect... What else could it be?
Bout to do an off grid setup, you know, kind of like my RV has from the factory.... Signature solar out in Texas sells the majority of the major components. Would really like to get everyone's take on an off grid setup applying the current code and knowledge.
How do we view the rest of this discussion? Thanks
I just started working for a solar company and I have found in my area that every local codes want different connections.
The raceway from service disconnect (where supply side connection is made) to solar primary disconnect.. some inspectors here in CT do not want the neutral bonded in the solar disconnect if we use a metal raceway because they say it creates a parallel path for the neutral back to the service first means of disconnect… thoughts Mike ?
Ian
The 2020 NEC makes it clear in 250.25, that we must bond the neutral to the case in accordance with 250.24.
Where can I find full video !!
This is kind of how my solar is connected except they used pins in my main panel right before the disconnect breaker. Which to me makes more sense compared to making that connection in the power companies box like in this picture.
Must be a electronic detector to time top dead center of the ( the inverter can ensure proper synchronization of the output waveform to grid voltage, frequency, and phase. In most inverter designs, a PLL provides the mechanism at the heart of this synchronization process ) if out of sink probably auto disconnect
Grid Tie
Y'all Sparkys sound more like lawyers than lawyers. This is hardcore word interpretation, especially difficult with new and changing technologies and products.
I agree on the double lug because any electrician in the future will see it, if it is hidden they may miss the challenge that they may have, ( ask fire marshals if there has been any accidents because someone missed it )
I don't because there are many many 400amp meter bases that come factory equipped with double barrel lugs. Milbank is one. I've even seen ones that are UL listed for 4...
Funny, I was reading article 705 last night
It could be fusible?
Line side connection 208 delta because primary solar is 480. Solar needs Neutral for reference only and we create with transformer.
No. 1 208V is not Delta.
No. 2 I don't understand what you mean by 480V.
No. 3 Solar PV does not create a transformer.
Can you tell me what solar array produces 480 volts? I never seen one in my life. As the highest rated PV panels I seen are 150 volts Ocv. And how the hell would you get 3 phase. Unless you had three solar panel arrays. Each at there own phase angles.
@@MikeHoltNEC My bad and sorry for late supply. Main service is 120/208. Our Solar inverters are 480/277 and neutral for inverter are for reference only. So we come from line side Utility into AC Disco with 208 no neutral. From disco to new reverse fed transformer with 208 to 480/277 . Then we install a disconnect after transformer 600v to new inverter. So its just the new inverter drawing thee 480v. Thank You and God Bles
@@WizzRacing Sorry bad info. The inverters we use are 480v and we use a transformer to convert. The inverters we use are Solar Edge 120k or smaller
we cant use double lugs unless provided by factory by code in my city
All terminals are listed for a single conductor, unless identified for two or more conductors [110.3(B) and 110.14(A).
Not sure why they used double lugs on the meter base..You can pass right over to the service disconnect. And accomplish the same thing. Thus any utilities would not care. As you made no changes to the meter socket....
That was a cliffhanger
we dont allow you to pass your load side past out line side because of transduction
Can you elaborate? Most of us are ignorant on this topic, even those in the video struggled to answer it.
Please explain in as much detail as you can provide. Thank you.
@@josegomez6549 well you have some of the magnetic residence from the conductor the insulation tries to stop most of it but as those conductors rub it will only increase therefore giving power past the meter
Where are the PV system ground rods?
There are none required, see 690.43.
@@MikeHoltNEC Must be an AHJ specific requirement. On a AC sub-panel here, when a power generating source is present, grounds rods must be added.
I don't like this diagram, what if the premises has two service disconnects and two PV disconnects. Bonding every neutral creates multi fault current paths thru the disconnecting means enclosures, and in the event of a fault, the enclosures and raceways could potentially become fault current paths. In this example in the video it's ok, because there's no EGC in the PV disconnect, so no multiple fault current paths, and also PVC was used for nipples between the switch enclosure and the meter base. On every system, it's better to stick with one and only one neutral bonding connection. One example is a large house I did with multiple PV disconnects, and two service rated generator transfer switches feeding two 200 amp panels as service disconnecting means. To avoid this problem, I ran EGC's to every switch, and the main GEC in this area is always attached to the neutral bar inside the meter base. The reason being this utility wants the EGC to be in the enclosure with the utility seal on the door, to prevent tampering of the GEC. Also, the main GEC is required to be in a conduit, and then to each grounding rod. Then a separate EGC is brought out for the telecommunications, CATV, satellite dishes etc. Because this utility doesn't want people attaching stuff to the main EGC. This way, the only place the neutral is connected to ground is only in the meter can, and all the service disconnects and everything else downstream of the meter base, the neutral is kept separate from ground. GEC is used to bond all the switches together. With the transfer switches this was easy, the manufacturer already had separate ground and neutral bars, so was easy to just remove the bonding jumper. In the 200amp PV disconnect switch, I just used the terminal block with the green bonding screw for the EGC, and the neutral just came from the meter base and directly to the inverter subpanel without any neutral connection to the disconnect switch itself. Some other jurisdictions like Florida I think also do it this way, seems to be more for areas that are prone to lightning strikes in which the GEC is ran into the meter can, and then every panel in the premises has to be treated like a subpanel, and no neutral to ground connections allowed anywhere on the premises except in the meter base, sealed by the utility. Makes for a safer system in my opinion.
The Question is: Do you bond your grounds and neutrals in the pv disconnect and purposely create a parallel path to ground?
Or do you isolate them and use the EGC to get objectable current back to the neutral? (just like a sub panel)
THE 0 point (neutral) is already established from the utility company and bonded why would we bond at the pv disconnect? this would create 2 paths to the main 1 on the ground 1 on the neutral... no?
the grounds coldwater,steel,rods, everything (likely to become energized) and the neutral is already established and bonded.
thanks.
Neutral and case is bonded in the supply side disconnect per 250.25.
@@MikeHoltNEC @MikeHoltNEC Thanks for the response, but wouldn't that create a parallel path on the ground and neutral? If you bond both the service disconnect and the pv disconnect? with MBJs??
Hey I just wanna make sure you understand that the bond between the neutral and ground in the PV system disconnect only occurs if your PV is connected on the supply side of the main service disconnect…
@@ianclifford31 yeah, I get that that is what the code says, I was wondering how that does not create a parallel path. also why would it matter if it is a back fed breaker or a supply side connection. I get that they are unprotected conductors( service side ) the neutral is from the utility and already bonded to the ground and the grounds are not sized per 250.66. thanks
There are no grounds on a PV system.. You have a hot and neutral..Only thing grounded is the solar array frame metal support. And that is grounded at the service.
And these can be wired in series or parallel. Why the smart people fuse each panel. That way if you lose a solar panel. You know which one it is...Just as you would fuse each parking lot light poles. If one goes bad. It does take them all down or the whole array..
You’re violating multiple codes by bonding the neutral conductor to ground in the PV disconnect enclosure. The PV system is not a separately derived system and is not service equipment.
Of course not, read 250.25, which is new for the 2020 NEC.
That drawing is incorrect for the solar pv
Not it's not...
@@MikeHoltNEC The drawing showing disconnect going through meter can. Solar paths are solar pv panels to inverter , to disconnect, and then main or sub panel line-side with piercing or back-fed breaker. During solar installation companies are not contacting utility companies to do a temporary disconnect to go into meter can or disconnecting it. Electrical plans I can send/email your way as an example. Only time companies needs access to meter can is if a battery is being installed for the ESS battery. Thanks for your work.
@@EvolveSolarOperations The NEC permits the 'supply-side' connection at any point on the supply-side of the service disconnect, including the meter as shown. Please review 700.11 in the NEC. If you don't like this 'option,' that's okay but it doesn't mean that others should not do it this way.
That looks nasty. There should be one service disconnect and only that should connect to the meter. The PV system should connect to the service disconnect. Switch the service disconnect off and everything is disconnected from the meter. Yikes.
No one knows....they can't even agree themselves
The utility should have been required to make all new smart metered with load side “secondary source “ metered lugs.
This is shocking news...Get it
Four nerds one disconnect?