12 Ga wire is not going to catch on fire, but the MC connectors might.
I just went back on a 7 yr old Solarworld install, and had a bad series
MC connector (module to module). It got quite crispy, deforming and
bubbling the plastic on both sides of the connection. It was still
passing current; I didn't get a chance to measure the volt drop. It was
completely plugged in, so not an installation issue.
This was not one of our connectors made up in the field, these were
Solarworld factory connectors on both sides, same model modules. That
also means no mismatch of "MC4" connector type.
10+ amps continuous, moist environment, 30F+ hotter than ambient temp,
all are tough on connectors. I predict more connector failures as
module current ratings increase.
Ray Walters
Remote Solar
On 11/9/2023 3:02 PM, Glenn Burt via RE-wrenches wrote:
Good luck trying to convince your customer that their house caught on
fire because of a manufacturers flaw, and you have no responsibility
for it…
It may be an out to shift the blame, but it only makes everybody get
some on them…
*From:* RE-wrenches <re-wrenches-boun...@lists.re-wrenches.org> *On
Behalf Of *William Miller via RE-wrenches
*Sent:* Wednesday, November 08, 2023 12:14 PM
*To:* RE-wrenches <re-wrenches@lists.re-wrenches.org>
*Cc:* William Miller <will...@millersolar.com>
*Subject:* Re: [RE-wrenches] Cable sizing for high current modules?
NEC interpretation/guidance?
George:
Appliance manufacturers have their own requirements that are not the
same as the NEC requirements. As long as you are not modifying the
manufactured assembly you are not responsible for compliance of that
appliance. By appliance, I mean the solar module, microinverter, etc.
William Miller
Miller Solar
17395 Oak Road, Atascadero, CA 93422
805-438-5600
www.millersolar.com <http://www.millersolar.com/>
CA Lic. 773985
*From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org]
*On Behalf Of *George McClellan via RE-wrenches
*Sent:* Wednesday, November 8, 2023 9:06 AM
*To:* RE-wrenches
*Cc:* George McClellan
*Subject:* [RE-wrenches] Cable sizing for high current modules? NEC
interpretation/guidance?
Team;
With the move to larger cells, some modules have an Isc that is
pushing the limits of 12 AWG wire. If I apply the rule of 156% (or
125% solar derate*125% continuous load derate) to an 18 Amp Isc module
this will exceed the 25A that a 12 AWG wire can carry. I understand
that the homeruns will need to be a larger AWG (10 ga), but do the
solar module cables (from junction box to MC4) also need to be
larger? Any guidance or reference material would be greatly appreciated.
Thx,
George McClellan | Senior Technical Sales Manager | REC Americas LLC
330 James Way Ste 150| Pismo Beach, CA 93449| USA
Cell phone +1 805 704 3226 | Fax +1 805 357 6104
www.recgroup.com <http://www.recgroup.com/> |
george.mcclel...@recgroup.com <mailto:shannon.k...@recgroup.com>
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