[RE-wrenches] GEC for Micro-Inverters and ACPV Modules

[John Berdner]

Mark:

The GEC is required if the inverter bonds one of the PV conductors to ground (as Enphase does).
Enphase support may not have a problem with it but not using a GEC (with all the GEC requirements) on any system with a grounded array is definitely a Code violation in NEC 2008 and 2011.
I don't recall it being eliminated in the 2014 Code either but could be wrong.

If the inverter does not bond the array positive or array negative to ground then the array is ungrounded so no GEC is required.
Non-isolated inverters (also referred to as transformerless inverters) do not bond the array negative or array positive to ground and so no GEC is required (EGC is still required).

If you have a Listed AC module then none of the DC side requirements apply so no GEC would be required unless required by the manufacturer's instructions.
Unfortunately, adding a micro-inverter to a module in the field does not make it a Listed ac module.

Best Regards,

John Berdner
General Manager, North America

SolarEdge Technologies, Inc.
3347 Gateway Boulevard, Fremont CA 94538 USA  (*Please note of our new address.)
T: 510.498.3201 ext 747
M: 530.277.4894


-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Mark Frye
Sent: Monday, January 14, 2013 3:31 PM
To: RE-wrenches
Subject: [RE-wrenches] GEC for Micro-Inverters and ACPV Modules

Does anyone have the latest on the GEC for micro-inverters/ACPV issue?

I know it is still in NEC 2008 and I believe 2011 with plans to address it in 2014.

I am specifically interested in the issue of GEC means continues (irreversible splices) and the whole business of the DC side of these devices constituting a separately derived system.

Enphase technical support is fine if the micro inverter chasis is bonded to a EGC only, but they leave the lug on the chasis if you want/need to build a GEC.

SolarBridge (pre-assembled micro-inverter) seems to be devoid of a chasis lug and therefore by extension does not/can not had a GEC in the system.

Exeltech (integrated micro-inverter aka. ACPV) does not seem to have a lug on its chasis.

Has the industry pretty much moved to not requiring a GEC for these devices and if so, how are the AHJ taking it?

Thanks,
Mark Frye
Berkeley Solar Electric Systems
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