Bare Copper

Status
Not open for further replies.
R

rrr_usty

Member
Location
Colorado
The application is a Grid-tie system on a flat roof with the inverters on the roof, the question is regarding the conductor from the inverter to the array, EMT is ran from the liquid-tite at the inverter to the array which is used to protect the PV wires(dc side) & the EMT has a connector & bushing on the end for protection.
(The EMT is basically a sleeve & the conductors are open to the atmosphere under the modules)
A ground wire needs to be pulled from the inverter to the array, some have indicated using bare # 6 Copper stranded & others indicated green THHN/THWN-2 is allowed & some have indicated THHN & at the end where the conductor is exposed to the atmosphere, just remove the insulation therefore leaving the bare copper exposed.

Thank you for your input.
 
Any of those are allowed under the 2014 code. Under previous codes any conductor in a raceway could not be solid if #8 or larger.

Pulling a solid wire larger than about #8 or #10 through a raceway is a pain-in-the-!@#$ and not worth the wasted time. I don't know why they allowed it for up to #6 in the 2014 code, as whatever reasons there were for banning #8 and larger (310.106(A)) still apply in my opinion.

Some inspectors will require a #6 ground for an exposed conductor on the array because of 690.46. This does not apply inside conduit. In places where that's not required, we usually do bare #10 solid copper on the array underneath panels, and a stranded THWN-2 in conduit.

There's really nothing in the code that prohibits using a stripped THHN/THWN conductor on the array, but using a small stranded conductor is not as mechanically sound and I would recommend against it.
 
So the issue is the rating of the wire.
Thhn is allowed inside of the conduit, where it emerges from the conduit & connects to the grounding post on the PV panel & the exposed portion of the insulation is not rated for an outside application.
If the insulation were to be removed from the thhn where it emerges from the conduit and then you would have bare copper.
bare copper is rated for outdoor applications, as this application is for grounding, would the thhn application be allowed?
 
I don't know if it is addressed explicitly anywhere in the code, but it is simply silly to prohibit using an exposed insulated conductor where a bare conductor would be allowed. It doesn't matter if the insulation is rated for the conditions, because it isn't needed.
 
jaggedben said:
I don't know if it is addressed explicitly anywhere in the code, but it is simply silly to prohibit using an exposed insulated conductor where a bare conductor would be allowed. It doesn't matter if the insulation is rated for the conditions, because it isn't needed.
Click to expand...

There you go again, applying logic to the Code. :D
 
I agree with Jaggedben:
use insulated wire in conduit and bare wire under array.

Details:
1. If the lay in lug on your bonding (grounding) bushing is rated for double lugging then transition there (lay both wires in it)
2. That lay in lug......you do replace that lug with a tin plated, copper lug, rated for direct burial, right? (you can tell by it's weight that it is copper) The original lug will corrode within a year to an unrecognbiazable lump from galvanic corrosion in the presence of moisture.


If not splicing in the lug......You can always use a split bolt to splice the ins. to bare.....as it is mechanically and electrically sound for a wire in air.

As for wire size: Remind the inspector if needed: this is not your DC GEC! This is the EGC.
 
Where is the code reference for 2014 that allows for #6 to be run in conduit for PV source circuit conductors?
 
Status
Not open for further replies.
Top