Question on NEC 250.32 outbuilding – 911
The electrical inspector is coming BACK tomorrow (Friday 3/16) and I’m going through the punchlist he left last time. I though I had it all figured out, but there’s one item I’m stumped on.
Situation: we have a potting shed that the prior owner ran power to from the main panel. Overhead wires in PVC conduit, just 6 feet away. 6/3 for the kiln, and two 12/2 for heat and lights. Well, I got dinged on this: the outbuilding only gets one wire (the 6/3), not 3) NEC 225.30. Fine. I’ll disconnect the others at both ends.
And I need a subpanel in the outbuilding. Fine. Got one.
But where I’m stumped is this:
“Buildings or structures supplied by feeders or branch circuits shall have a grounding electrode or grounding electrode system installed in accordance with 250.50. The grounding electrode conductors shall be connected in accordance with 250.32(b)”
So.. I looked up 250.32(b) in the Washington State L&I code, and it starts talking about equipment grounding. Ok, fine. Run a bare #10 (or #6?) to the subpanel frame, not the ground/neutral bars. But that’s just one end, where does the other end go?
1. To the other panel? In the house, all grounds are connected. The neutral/grounds are wired to the equipment, wired to the plumbing and a 5/8″ rod.
2. to the Earth? with a 5/8″ galv ground rod? Might be… and if so, would that solve the “grounding electrode” business?
Replies
A ground rod is a grounding electrode. You definitely need a ground rod for your panel.
They won't sell you a gun if you are crying.
http://thewoodwhisperer.com/
you got to have 4 wire to main and a ground rod driven at out building
If the two panels aren't connected by a metal raceway then you don't need the ground from the main panel.
They won't sell you a gun if you are crying.
http://thewoodwhisperer.com/
my favorite county inspector wrote me up on this matter. 4 wire no matter what. so thats what I did. and my building 80 feet away with pvc conduit
They all read it their own way. :)
They won't sell you a gun if you are crying.
http://thewoodwhisperer.com/
Yep, makes sense. Just got back from the hardware store, 30 bucks lighter.
Greetings from somewhere else in Washington. They are probably going to require (2) 5/8" x 8 ground rods driven all the way in, not closer than 6' from each other, with a ground wire from the subpanel... I think that'd be #6 copper but you better check. Anything more than 5 feet of metal water pipe (or gas, I suppose) is going to require bonding also.
I hope you're wrong on that 2 rod thing... I just have one. After all, it's not for current grounding, just the equipment ground.
Oh, and by the way, I just got done pounding in the ground rod and that was the sweetest ground rod I ever sunk into earth.. it must have gone in 1-2" per whack of the 5 lb hammer. Done in no time!!
(and if I DO need another rod, it won't take long to install)...
Well, we passed! And I found out the mysteries of outbuilding grounding (at least as far as my inspector is concerned):
#6 solid copper from 8' galv ground rod to a strip attached to the panel box.
All copper grounds including the feeder ground go to this strip.
White/red/black to the bus and insulated neutral bar, and all white neutrals to that insulated neutral bar.
And one rod was enough to satisfy him.
-- pshew! We only had to put the sheetrockers off one week.