[RE-wrenches] GEC for Micro-Inverters and ACPV Modules
John Berdner
John.Berdner at solaredge.com
Wed Jan 16 09:53:14 PST 2013
Brain:
Not trying to be argumentative here...
I understand that you feel that a WEEB is equivalent to an irreversibly spliced connection but, as most commonly used in the field, I disagree.
The Code does not recognize bolted connections of any kind as equivalent to irreversible spliced or contiguous.
It is an issue of the type of connection not the presence of the WEEB clip in that connection.
For Example: If the WEEB connection was riveted in place then I believe it would be considered irreversibly spliced but as part of a bolted connection, no.
With specific reference to GEC see 250.64C in the 2011 NEC or 2011 NEC Handbook.
Lastly, the argument that it is a similar level of difficult to cutting the wire, while true, is not relevant to the Code requirement. Cutting a contiguous wire is also a similar level of difficulty to opening a bolted connection but obviously a bolted connection is not a contiguous wire.
Best Regards,
John Berdner
General Manager, North America
[cid:image001.jpg at 01CDF3CC.8AE7FDF0]
3347 Gateway Boulevard, Fremont CA 94538 USA (*Please note of our new address.)
T: 510.498.3201 ext 747
M: 530.277.4894
From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of August Goers
Sent: Wednesday, January 16, 2013 9:22 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] GEC for Micro-Inverters and ACPV Modules
Thanks Brian. This has been a helpful thread for me. Mark Frye, thanks for kicking it off.
Best, August
August Goers
Luminalt Energy Corporation
1320 Potrero Avenue
San Francisco, CA 94110
m: 415.559.1525
o: 415.641.4000
august at luminalt.com<mailto:august at luminalt.com>
From: re-wrenches-bounces at lists.re-wrenches.org<mailto:re-wrenches-bounces at lists.re-wrenches.org> [mailto:re-wrenches-bounces at lists.re-wrenches.org<mailto:re-wrenches-bounces at lists.re-wrenches.org>] On Behalf Of Brian Wiley
Sent: Tuesday, January 15, 2013 1:02 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] GEC for Micro-Inverters and ACPV Modules
Hi August,
I maintain that the WEEB is an irreversible splice.
If you want to disconnect a WEEB from a structure, you must irreversibly damage the device. It cannot be reused.
Admittedly the force required to remove a WEEB is less than that required for a thermal splice, but it doesn't take much force to just cut a wire either.
I would argue that the intent of the code is to prevent inadvertent removal of the ground. You must knowingly remove a WEEB from the grounding path and if you do so in the maintenance of an array, good workmanship requires that you restore the connection.
Best Regards,
Brian Wiley
On 1/15/2013 2:11 PM, August Goers wrote:
Hi John,
I definitely see your point and that is why I was somewhat questioning the
use of WEEBs with Enphase below. Enphases's instructions (link posted in
thread below) seem to indicate a support of running the continuous GEC on
the rack and then bonding the microinverter to the rack with WEEBs. Maybe
I am misinterpreting the document or perhaps Enphase has another take.
There is no question that according to NEC 250.64(C) the GEC must be
continuous. In the 2008 NEC handbook section 690.42 Point of System
Grounding Connection has an application note "Connections are to be made
in accordance with markings on the equipment or in the installation
instructions."
All that said, it seems like technology is leaning towards listed AC
Modules or floating array inverters. It sounds like that removes the
requirement for a GEC which is great to help reduce installation costs.
The GEC has always been a pain in the neck.
Best,
August
-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org<mailto:re-wrenches-bounces at lists.re-wrenches.org>
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of John
Berdner
Sent: Monday, January 14, 2013 7:07 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] GEC for Micro-Inverters and ACPV Modules
August:
The WEEB or other Listed grounding means between the inverter case and the
structure are not "contiguous or irreversible spliced" and therefore do
not meet the requirements for a GEC.
If the structure is then grounded via a bolt on lug it also is not
irreversible or contiguous.
If you can unbolt something and disconnect the ground then it is not
contiguous or irreversibly spliced.
Both of the above are ok for EGC but not for GEC.
GEC is a pain in the neck but the Code requirements are clear.
If the PV array conductor (pos or neg) is bonded to ground by the inverter
then the inverter requires a GEC with all the related requirements - no if
and's or but's.
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>
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of August
Goers
Sent: Monday, January 14, 2013 4:32 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] GEC for Micro-Inverters and ACPV Modules
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>
[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
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches at lists.re-wrenches.org<mailto:RE-wrenches at lists.re-wrenches.org>
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm<http://www.re-wrenches.org/etiquette.htm>
Check out participant bios:
www.members.re-wrenches.org<http://www.members.re-wrenches.org>
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches at lists.re-wrenches.org<mailto:RE-wrenches at lists.re-wrenches.org>
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm<http://www.re-wrenches.org/etiquette.htm>
Check out participant bios:
www.members.re-wrenches.org<http://www.members.re-wrenches.org>
CONFIDENTIALITY NOTICE: This e-mail and its attachments are intended only
for the use of the individual or entity who is the intended recipient and
may contain information that is privileged, confidential and exempt from
disclosure or any type of use under applicable law. If the reader of this
e-mail is not the intended recipient, or the employee, agent, or
representative responsible for delivering the e-mail to the intended
recipient, you are hereby notified that any dissemination, distribution,
copying, or other use of this e-mail is strictly prohibited. If you have
received this e-mail in error, please reply immediately to the sender.
P Please think of the environment before printing this email
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches at lists.re-wrenches.org<mailto:RE-wrenches at lists.re-wrenches.org>
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm<http://www.re-wrenches.org/etiquette.htm>
Check out participant bios:
www.members.re-wrenches.org<http://www.members.re-wrenches.org>
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches at lists.re-wrenches.org<mailto:RE-wrenches at lists.re-wrenches.org>
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm<http://www.re-wrenches.org/etiquette.htm>
Check out participant bios:
www.members.re-wrenches.org<http://www.members.re-wrenches.org>
CONFIDENTIALITY NOTICE: This e-mail and its attachments are intended only for the use of the individual or entity who is the intended recipient and may contain information that is privileged, confidential and exempt from disclosure or any type of use under applicable law. If the reader of this e-mail is not the intended recipient, or the employee, agent, or representative responsible for delivering the e-mail to the intended recipient, you are hereby notified that any dissemination, distribution, copying, or other use of this e-mail is strictly prohibited. If you have received this e-mail in error, please reply immediately to the sender.
P Please think of the environment before printing this email
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20130116/19818267/attachment-0003.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.jpg
Type: image/jpeg
Size: 13992 bytes
Desc: image001.jpg
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20130116/19818267/attachment-0006.jpg>
More information about the RE-wrenches
mailing list