I’m hoping you can help me understand sub panel wiring. It seems to me that this panel is wired incorrectly. Apparently a licensed electrician did the work, but something is not sitting well with me.
The main power feed is to a panel in the garage. This panel is fed from that panel in the garage, making it a sub panel.
Should there not be a 4 wire feed from the main panel? 2 supply, neutral and ground.
They have twisted together the bare wires in the supply cable to create a neutral, and run a separate ground to the copper main water supply. OK, I can see how that might work, but they’ve bonded that ground to the neutral bus. That’s a serious no no is it not?
The fix I can see is to remove the ground from the neutral bus and attach it to the short bar to the left of the neutral bar, as shown in the last pic.,(thereby grounding the panel) and to pull the bonding jumper screw in the top of the neutral bus in the center of the panel.
I know the proper protocol is to have a licensed electrician evaluate. I’m trying to understand for myself what is going on. (besides, a licensed electrician did the work!)
Prior to the 08 NEC a three wire feeder was allowed to outbuildings if no metallic path existed between the two buildings. The panel was bonded neutral to ground the same as a service panel.
A three wire feeder is allowed to remain under the NEC. A new installation would require a 4 wire feeder.
Just so I’m clear: The wiring is OK based on 08 NEC (there is no metallic path), but because this work was completed in 2010, the feed should have been 4 wire.
Seems the electrician was not up to date with his code knowledge.
Also turns out the City inspector only looked at the work done in the garage. Never came inside to check the replacement panel inside.
Thanks again for your help. It’s always great to learn something from the experts!
Cheers-
Mitch, sometimes the adoption of the latest NEC is several years after the date of the code. As such the 2010 install may still have been under a code prior to the 08.
Here I know of one jurisdiction that was still on the 93 up until 2002.
Very good point you’ve brought up Jim. We sometimes tend to forget this when onsite looking at an install. Thanks as usual for your insight and knowledge.
Don’t forget gentlemen, Mitch is from Edmonton, and the NEC does Not apply.
Mitch, I can’t really tell from the pictures you posted and would have to look at the service. I would be very glad to come out and let you know if the work is done properly.
Yes Erik, there is a sticker on the panel. On closer inspection it turned out it’s for a sewer backwater valve! There is a sticker on the panel in the garage for the service. Apparently the inspector didn’t get inside the house.
