IS it True? Code requires conduit for panels runs less than 30 volts?

Photowhit · February 2010

OK,

I don't think I have a dog in this fight, but perhaps I should.

I was reading about low voltage Evergreen panels reverting back to J boxes as the 2008 code requires wiring in conduit for " ...accessible arrays with maximum system voltages of more than 30 V per the 2008 National Electrical Code’s Article 690.31(A). "

Article in Home power here;

http://homepower.com/article/?file=HP134_pg12_TheCircuit_7

I have an array that is ground mounted and fixxed. Running 24 volt nominal (@35v vmp) The way I read it, any 24 volt system or 12 volt running an MPPT controller running 12v panels in series would be required?

I guess the panels I added last year should have the wiring run in conduit?

At some point this just gets silly. Glad we have no one coming out to check NEC code.

I have the 2008 code on a different computer, this is a bit demanding, so upgrading/reconfiguring people will have to basiclly remove the fixed wires and instal a junction box? Will old panels be exempt for their life? Is John Wiles mad?

crewzer · February 2010

Re: IS it True? Code requires conduit for panels runs less than 30 volts?

"Raceway" (conduit, etc.) is required for systems with >30 V "maximum system voltage" (per NEC 690.7?) if the cabling is "readily accessible". I'm unable to find a definition for "readily accessible".

An early lesson I learned as a designer was the difference between "fool" proof and "damn fool" proof.

HTH,
Jim / crewzer

niel · February 2010

Re: IS it True? Code requires conduit for panels runs less than 30 volts?

" Is John Wiles mad?"

i've been wondering that myself as he does seem to be getting a bit punch drunk with his self appointed power over aspects of solar. if b franklin was around he'd have him running rope sized string and fuse the string after running it through his home first through conduit and needing a special mc4 connector made for string!

:grr

bottom line is we wouldn't have it discovered by mr franklin and he probably wouldn't have done it due to over regulation that is senseless.:grr

dsp3930 · February 2010

Re: IS it True? Code requires conduit for panels runs less than 30 volts?

There is a nice summary of what you are asking about that was developed for the Interstate Renewable Energy Council.

My read from this is, you need conduit covering anything that is 8' or lower that is exposed ... anything higher and it can be uncovered if the wire is rated for exposure. (IE. PV wire with MC connectors )

Short excerpt from:
[ Field Inspection Guidelines for PV Systems (2009 DRAFT) - http://www.brooksolar.com/files/Field_Inspection_Guide-8-19-accepted.pdf ]

Wiring not readily accessible

A common misunderstanding in the field relates to
wiring within a ground-mounted array. The 2008
NEC specifically requires that array conductors be
in a raceway or not readily accessible. Since
module wiring cannot be placed in raceways due
to the plug connectors used universally in the PV
industry, the wiring must be rendered “not readily
accessible.” Making wiring not readily accessible is
easier than some may initially think. Ready access
implies that anyone can walk up to the array and
touch the wires. Wiring is not readily accessible in
the following example situations:
1. Where conductors are protected by a fence
only allowing authorized personnel.
2. Where conductors are above 8 feet from the ground.
3. Where conductors are protected by guards that require tools to remove the guards.

Another neat guide when preparing for a NEC code review:
Inspector Guidelines for PV Systems (2006 FINAL)
http://www.irecusa.org/fileadmin/user_upload/NationalOutreachPubs/InspectorGuidelines-Version2.1.pdf

crewzer · February 2010

Re: IS it True? Code requires conduit for panels runs less than 30 volts?

Bill Brooks to the rescue! 8)

Thx,
Jim / crewzer

audredger · February 2010

Re: IS it True? Code requires conduit for panels runs less than 30 volts?

1. Where conductors are protected by a fence
only allowing authorized personnel.
The fence is an electric fence....?

3. Where conductors are protected by guards that require tools to remove the guards.
Ok, the "guards" have 9mm's and it takes a 357 to remove them! LOL

BB. · February 2010

Re: IS it True? Code requires conduit for panels runs less than 30 volts?

Some of the access arguments got real silly at times as we where designing equipment... Was a screw slot that could fit a dime "tool-less"... Was a straight slot screw too common of tool, was a Phillips? Did a large door have to have a key... How would we protect against somebody with a Leatherman tool.

But some of the "mistakes" in designs were pretty gruesome too... The first RJ 45 telephone/Ethernet wall socket standard connector--The ends of the internal spring contacts just floated in free in the socket. Small kids would stick their fingers in the socket and get their fingers "fish hooked" inside.

-Bill

wtwoods_az · February 2010

Re: IS it True? Code requires conduit for panels runs less than 30 volts?

Many years ago, in a different life, the red phone went off at our ambulance ready room in North Adams MA. There was a guy on the other end yelling and speaking mostly Greek with a little (kinda) english mixed in. After a minute, I was able to get him to calm down enough to give me an address and Jimmy and I hit the street lights and siren. A 3 minute run, we grabbed jumpkits and headed for the door with Papa screaming from the doorway. Inside we found a crying 4 yr old son and, of course, Greek Papa yelling at us to "do something" (I think). Turns out the Papa ran a pizza place till late the night before and was "watching" the son during the morning (aka sleeping on the couch). The kid Loved his Dad's big key ring, full of lots of keys. He got them from snoozing Papa's belt and promptly plugged them in to the nearest socket. Boom. Lights out, sreaming kid, call to us.

He was fine. The keys took the current, nothing thankfully up the arms and thru the chest or I wouldn't be writing this story. A tiny flash burn on a finger which I spent a ton of time on - he loved the attention and my kit, stopped crying and mostly played with my stethoscope. Papa on the other hand was still a mess. Jimmy finally got him to calm down by starting him on the paperwork. All ended well. Laughed all the way back to the station talking about what it must have been like for the poor guy when it went boom, and what the explaination to Mama would be like later.

Now I know that since then they've come up with a multitude of kid-proofing stuff, but I think that kid could have overcome that "must use tool" had it existed at the time. You cannot kid or fool-proof everything. At some point you need to rely on your common sense.

My homebuilt trackers are not 8 feet off the ground. I am not going to re-engineer them or install conduit. I do not climb transmission towers for obvious reasons. I expect that anyone in my backyard use at least that much common sense.

IS it True? Code requires conduit for panels runs less than 30 volts?

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