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

August Goers august at luminalt.com
Mon Jan 14 16:31:49 PST 2013


Hi Mark,

There have been some recent threads on this list touching on this topic.

As far as I understand, Enphase microinvertes still require a GEC up to
and including the 2011 NEC. I don't know about the 2014 NEC. Enphase bonds
the positive DC module conductor to ground. Pages 16 and 17 of their M215
installation manual address grounding:

http://enphase.com/wp-uploads/enphase.com/2011/06/Enphase_M215_Installatio
nOperation_Manual.pdf

Products such as Solar Bridge that are listed as Alternating Current (AC)
Modules (per NEC 690.2) don't need a Grounding Electrode Conductor (GEC)
as long as there are no conductors connected to ground within the product.
Solar Bridge has a good article on this:

http://solarbridgetech.com/microinverters-and-ac-pv-modules-are-different/

This all takes us back to using Enphase with grounding washers like WEEBs
for the GEC. According to what I read in their instructions (and after
many phone calls), it sounds like they are okay with us running the GEC on
the racking in #6 and then bonding the microinverters to the rack with
WEEBs. Seems a little strange but it's been working for us.

Good topic!

Best,

August
415.559.1525


-----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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