I just moved my shop to a new location here in sunny North Hollywood CA and was looking over the electrical panel and noticed there is no ground wire coming in from the service entrance. There is a 200 amp main on the outside rear wall and that feeds the inside panel about 30 feet away. Here are pics of both.

I'm wondering if I need to hire someone to come out or if this appears ok. Thanks for any info! My buddies shop just had an electrical fire so super on edge about it!enter image description hereenter image description hereenter image description here

  • I'm a Canuk so I'm not up on NEC codes, but it appears to be bonded through the metal raceway (conduit) from the service entrance to the panel. – Connor Bredin Feb 2 '17 at 2:10
  • Yep, particularly given the nice clear demarcation of grounds and neutrals, which what looks to be an isolated/insulated buss for the neutrals. Connor, you should make that an answer. The open/unused holes on top of the panel should be plugged, and I'm less sure of the connection between the ground bar and the case, from the picture. But I think "Conduit as grounding conductor" is right on the money. – Ecnerwal Feb 2 '17 at 2:50
  • Yeah there is no connection between that ground bar and case. Both of those bars are insulated and just bonded together. Also, I just realized that it looks like there is a fourth wire coming in from the service entrance but that is just a pull wire that has curled up from another conduit – Tim Feb 2 '17 at 2:58
  • I just uploaded a better lit picture. Thanks for the help guys! – Tim Feb 2 '17 at 3:05
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    @Tester101 The black 'strap' is a metal bar wrapped with heat shrink, bonding the neutral (and ground in this case) bars together. There would be continuity between both and to the enclosure from either, as the neutral is bonded to ground at the disconnect. In Canada (or Alberta at least), both sides are always only for ICs (neutrals), which can then be bonded (or not) depending on the application. We always have a separate ground bar attached to the enclosure. In this case, the main neutral is also acting as the ground (separate from the metal raceway). – Connor Bredin Feb 3 '17 at 2:04

We see a lot of really bad electrical work here. This is not that. I wouldn't lose any sleep if my panel looked like this. There are a few defects.

If you're really worried about electrical fires, inspect all your wiring and install AFCI breakers on all the circuits which are not in steel conduit, or which have flexible cords plugged into them.

Ground doesn't necessarily come from the service entrance

Nothing says the ground must come in from the service entrance. The two hots and neutral do. Ground is derived from rods, water pipe, etc. and brought into the main panel/breaker.

Your situation is a little unusual since you have a main breaker in a different box from the main panel (which does not have a main breaker). It appears your ground comes into the main-breaker box. Make sure it goes to somewhere which is an actual legal ground.

You can see where it bonds to neutral there, and then bonds to the case through a flat strap. This is the only place ground should bond to neutral.

Ground is carried from the main breaker to the main panel via the metal conduit. Metal conduit is a valid grounding path.

Is neutral tied to ground in the main panel?

The main panel has all its neutrals neatly separated from all its grounds. That suggests good work. However, I am concerned that it appears there's a bond between the neutral bar and the ground bar, and I don't entirely see how the ground bar is bonded to the actual metal case of the breaker panel. There should not be a neutral-ground bond in more than one place.

Fill the empty holes in the panel

The knockout holes should be capped. They make plugs just for that. But first...

Too many conductors in that conduit

Look just to the right of the main cable entrance, you see a conduit with 5 hots and 5 neutrals going into it. If the conduit is longer than 24", that's too many - the maximum is 4 circuits per conduit**.

So, lay a second parallel conduit and move 2 of the circuits to it. Don't pick any 4 random wires, always keep hot together with its partner neutral.

If you must put 5-10 circuits in a conduit, you must de-rate, meaning use thicker wire: 12 AWG for a 15A circuit, and 10 AWG for a 20A circuit.

** The gory details are in NEC 310.15b3a. You are allowed up to 9 conductors in a single conduit, regardless of size. Grounds don't count. In a 240V circuit, neutrals don't count since they only carry imbalance current.

Above 9 wires, you have to "de-rate" wire capacity. For 10-20 wires, use 12AWG for a 15A circuit or 10 AWG for a 20A circuit. For 21-40 wires, use 10 AWG for 15A, or 8 AWG for 20A.

  • Great info Harper! Yes there is a bond between the neutral bar and the bar that the grounds are on. It's the isolated black bar running horizontally there. I'm not sure if that is removable. Also, I don't think the ground bar is tied to the panel. I see what you are talking about on the conduit with too many circuits. I will address that. – Tim Feb 2 '17 at 5:48
  • @Tim Surely, since it must be removed in a sub-panel (which this effectively is). Just make sure the ground bar is tied back to the grounding cable one way or the other. – Harper - Reinstate Monica Feb 2 '17 at 6:04

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