[RE-wrenches] EMT in attic

[David Brearley]

+1. John Wiles is awesome—and he would never mistake PV source or array circuits for a service. Not only are PV power circuits not a service, but PV systems (inverter output circuits) are not a service. The NEC defines all of this as power production equipment (705.2). 

By definition a service can only be provided by a "serving utility" (Article 100). That definition does not apply to PV systems. Having said that, Section 230.82(6) does allow PV systems to connect to the supply side of a service disconnect. But that allowance doesn't magically change the PV system into a service; it is still (parallel) power production equipment.

If you're still in the planning phase, Nick, it is a good idea to see if they will allow you to use MC "that complies with 250.118(10)" according to 690.31(E) in NEC 2011. 

DCB


On Nov 9, 2012, at 7:44 AM, Dave Click wrote:

> Nick, what the AHJ is telling you may actually be in reference to 250.97; for most PV output circuits (yes these are necessarily dc) this bonding requirement applies since array VOC > 250 VDC. As Kent just pointed out, these dc conductors clearly don't meet the NEC definition of a service.
> 
> "250.97 Bonding for Over 250 Volts. For circuits of over 250 volts to ground, the electrical continuity of metal raceways and cables with metal sheaths that contain any conductor other than service conductors shall be ensured by one or more of the methods specified for services in 250.92(B), except for (B)(1)..." followed by an exception.
> 
> Seems that FMC is OK as an EGC if your conductors have <20A OCPDs, which I imagine you do, but that FMC also can't be longer than 6' (see 250.118(5)). So I think your AHJ is probably right and I just learned something. If you're running a separate EGC anyway, you may want to ask why this bonding business is so important-- but I don't have an NEC reference on this to help you argue this. Maybe the AHJ would allow you to just run MC cable as the 2011 NEC allows.
> 
> John Wiles is awesome. Someone on this list had to say it.
> 
> DKC
> 
> On 2012/11/8 23:22, Nick Vida wrote:
>> Hi Wrenches,
>> 
>> Thanks for you comments. Fun for the day is hearing they want to apply
>> section 230 about service conductors and say that flex is not
>> a metallic raceway because it is no good for bonding. They are defining
>> the pv source circuits as a service.
>> I am getting a distinct Wiles vibe here.
>> 
>> I find it so annoying when they try to put out these distinctions with
>> no code, no city ordinance and not even an internal memo, especially
>> when they remain obstinate without going to the trouble to actually
>> legitimize the interpretation.
>> 
>> Dan- are the output circuits necessarily DC? I would have to look at NEC
>> for a minute, but it doesn't seem to add up to me right now.
>> 
>> Thanks,
>> 
>> Nick Vida
>> 
>> 
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