Jim, Hope all is well with you and yours. on white wires in circuits, In 3
ph. circuits you can get killed breaking into a neutral that's common to other
circuits. One example, working on 277 lighting, you throw the breaker or light
switch on the one circuit you're working so the hot isn't hot anymore. It's
standard practice for 3 ph. lighting ckts to share a neutral. The white wire
in your ckt is wire nutted in the j-box up in the ceiling to the common
neutrals. Those neutrals are hot to ground when their respective ckts are hot
and they're carrying current.
Just thought it was worth mentioning on this list that there's no hard fast
rule that all white wires are dead. It depends on the ckt.
Best,
Greg Egan
Remote Power Inc.
Message: 11
Date: Fri, 12 Jun 2020 15:17:19 -0500
From: James Jarvis<j...@aprsworld.com>
To: RE-wrenches<re-wrenches@lists.re-wrenches.org>
Subject: [RE-wrenches] White wire for DC- after ground fault breaker
Message-ID:
<CAFWEuYVMACXebixHtyRVYQ5Xnmaur=ugtv6etu5tnepm00n...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Hello Wrenches,
I have an off-grid install where I was recently red-tagged by the state
inspector. System is 24 volt with battery, Magnum inverters, some Magnum
charge controllers, and a Morningstar charge controller. It is permitted
under NEC 2017.
One of the inspectors issues was that my DC- conductors to the array /
rapid shut down box are black color. He wants them to be white because he
says they are solidly grounded. I reason that they are only solidly
grounded when they are solidly grounded. As soon as the ground fault
protection breaker opens, they are floating at array voltage. I think it is
misleading and unsafe to have a white conductor that can have hundreds of
volts of potential on it when a breaker trips.
I haven't dug into the code yet. I'm just working on the logic that one of
my mentors put into me which is white wires better not have voltage
potential on them. "That's the sort of sh*t that kills electricians" is
what he repeatedly said ... and it's stuck with me.
Thoughts? I'm backed into the corner with the state, so I will be changing
them to white even if it is unsafe ... unless I have some code backing.
<rant>Changing the wires to white will get interesting up on the roof. I
wonder if they want me to cut off the black MC on the modules and replace
them with white? This is mostly just an exercise in the State of Minnesota
only wanting to know about and allow micro inverters. They brought in a
state inspector from three hours away who kept repeating that he was a
"highly qualified individual", but was unable to identify or recognize a
charge controller. He kept referring to the charge controllers as
inverters.</rant off>
Thanks,
-James Jarvis
APRS World, LLC
+1-507-454-2727
http://www.aprsworld.com/
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