Concern about an old breaker box.

[djjsr]

I think I have a problem and need some professional advice.

I have an old building containing a lot of equipment and 2 large breaker panels that seem to be working fine. But there's a subpanel that I think may be a problem.

It's an old Federal Pacific panel that powers a bunch of wall outlets. It was probably installed back in the 1960's. It contains 40 breakers, all 120 volt 15 amp. Only 10 of the circuits are being used. 8 of those 10 are run in conduit but the other 2 are romex.

Over the years, the previous owner replaced most of the original 2 hole wall outlets with 3 hole grounded outlets, but no ground wire was added. Apparently the conduit is grounded. Using one of those plug-in testers, all outlets on all circuits test ok for ground.

I looked inside the breaker panel and found 3 neutral bars at the bottom, at least I think they are neutral bars but I don't know for sure. All neutrals are connected to 1 of these bars BUT the 2 ground wires from the 2 romex circuits are also connected there.

I am NOT an electrician but connecting ground wires to a neutral bar doesn't seem right.

I guess I have 2 questions:

1) How do I check to see if 1 of those 3 bars in the bottom of the box may actually be a ground bar?

2) If there is no ground bar, what should I do with the 2 ground wires from the circuits run with romex?

My plan is to get the Federal Pacific panel replaced. It looks like a very poor design where the breakers connect and I've read about problems with these panels. But in the short term I'm trying to be sure it's safe.

Thanks in advance if you can offer advice.

 

[wyliesdiesels]

Can u post some pics please? Hard to tell what exactly youre describing without seeing it.

But yes, neutrals and grounds should always be separated in sub panels and the neutral bar(s) should be isoated/insulated from the panel enclosure. However, u may have a 3-wire feed which makes this not possible to do!

And yes, FPE panels are junk, and have been responsible for many house fires!

 

[pattenp]

In a sub-panel what makes a bar a ground bar is it is bonded to the case and all grounds are landed on it with no neutrals landed on it. The neutral bar is insulated from the case with only neutrals landed on it. So in the sub-panel the neutrals and grounds should be separate with the neutrals being isolated from the ground. Also see if the feeder wire to the sub-panel is 4 conductors. If the sub-panel doesn't have a separate neutral and ground wire coming from the main, only a 3 wire feed, then leave the neutrals and grounds together in the sub-panel. The grounds on the romex need to be connected one way or the other.


Edit: wylie beat me. I didn't mean to repeat what he just said.

 

[djjsr]

There are only 2 (BIG) wires feeding this sub-panel. One goes to the top and feeds all of the breakers and the other connects to the neutral bars at the bottom. No ground wire at all. I think the outlets test ok for ground because some of the conduit is in the slab???

I will check to see if any of the "neutral" bars are actually connected to the housing. There are 3 bars, all mounted parallel to each other but only 1 is being used for the neutrals. Maybe one of the other 2 is actually a ground bar. I'll check.

 

[pattenp]

Sounds like the panel only supplies 120V. Is the feeder supplied through metal conduit?

 

[trainer]

Probably time to have an electrician take a look and advise you on what it'll take to bring it up to current code.

 

[KenB]

Probably time to have an electrician take a look and advise you on what it'll take to bring it up to current code.

Yes, that.


Ken

 

[wyliesdiesels]

There are only 2 (BIG) wires feeding this sub-panel. One goes to the top and feeds all of the breakers and the other connects to the neutral bars at the bottom. No ground wire at all. I think the outlets test ok for ground because some of the conduit is in the slab???

I will check to see if any of the "neutral" bars are actually connected to the housing. There are 3 bars, all mounted parallel to each other but only 1 is being used for the neutrals. Maybe one of the other 2 is actually a ground bar. I'll check.

Negative! Contrary to popular misconception, the earth does NOT establish nor act as an equipment grounding conductor aka the grounding on an outlet! The earth and ground rods are for lightning protection only!! This is confused by millions of folks because the 2 things(EGCs and lightning grounding) share the same word- GROUND!

However, your outlets will have a proper EGC/grounding connection if they are fed by metal conduit and are either housed in metal junction boxes or plastic j boxes with a green pig tail going to a conduit bonding nut!

Probably time to have an electrician take a look and advise you on what it'll take to bring it up to current code.

If this is indeed an old system, then theres no requirement to bring it up to current code as 3-wire feeds(if 240v) or 2 wire feeds(if 120v) were allowed back in the day and thus it would be grandfathered in.

 

[pattenp]

Wylie didn't say the earth wasn't a ground. He was saying electrode/earth grounding and equipment grounding are two different things. Each has its own requirements under the NEC.

Actually the earth is a ground... We ground electricity by inserting rods in the ground all the time...

 

[wyliesdiesels]

thx pattenp! Sometimes people just really don't pay attention!!!

 

[djjsr]

Ok, my brain is clouding up again thinking about grounding.

My wall outlets are all mounted in metal boxes connected by metal conduit to the breaker box. There are no ground wires anywhere. The box is all 15 amp 120 volt breakers (no main) and is fed from the main power panel by only 2 big wires connecting to the breakers and neutral bars. The big wires are not in metal conduit.

All of the wall outlets test ok for grounds and I'm not sure why since there is no dedicated ground lead and no metal conduit connecting this breaker box to the main panel.

BUT this box is mounted in a metal rack that holds some of the conduit AND it also holds a couple of big 1 1/2" diameter copper water pipes that are part of a system that is partially under ground.

Is it possible that my tester is showing a good ground because of the water pipe connection? If so, is that acceptable?

btw - I am getting an electrician to replace this breaker box hopefully in the not too distant future. But I've got too many irons in the fire to do it right away.

 

[wyliesdiesels]

Ok, my brain is clouding up again thinking about grounding.

My wall outlets are all mounted in metal boxes connected by metal conduit to the breaker box. There are no ground wires anywhere. The box is all 15 amp 120 volt breakers (no main) and is fed from the main power panel by only 2 big wires connecting to the breakers and neutral bars. The big wires are not in metal conduit.

All of the wall outlets test ok for grounds and I'm not sure why since there is no dedicated ground lead and no metal conduit connecting this breaker box to the main panel.

BUT this box is mounted in a metal rack that holds some of the conduit AND it also holds a couple of big 1 1/2" diameter copper water pipes that are part of a system that is partially under ground.

Is it possible that my tester is showing a good ground because of the water pipe connection? If so, is that acceptable?

btw - I am getting an electrician to replace this breaker box hopefully in the not too distant future. But I've got too many irons in the fire to do it right away.

If the neutral bar in the subpanel is bonded to the panel enclosure, then this is how your outlets are testing good for grounding. The yoke/chassis on regular outlets is connected to the ground pin. So if the outlet is in a metal box fed by metal conduit then its bonded to the neutral bar in your subpanel! No, the underground water pipe has nothing to do with it.

If u do upgrade the panel, just be aware that you would have to put in a new feeder to bring it upto current code. Is this subpanel in the same building as the main service?

 

[djjsr]

If u do upgrade the panel, just be aware that you would have to put in a new feeder to bring it upto current code. Is this subpanel in the same building as the main service?

Yes, the subpanel is in the same building, about 30 feet away from the main service. When the old subpanel is replaced, if the existing feed wires are large enough, can't a ground wire just be added to be code compliant?

Also, does this kind of job normally require a permit and inspection? It's a commercial building, if that makes any difference.


I really appreciate the advice.

 

[wyliesdiesels]

Yes, the subpanel is in the same building, about 30 feet away from the main service. When the old subpanel is replaced, if the existing feed wires are large enough, can't a ground wire just be added to be code compliant?

Also, does this kind of job normally require a permit and inspection? It's a commercial building, if that makes any difference.


I really appreciate the advice.

Yes, u can add a ground wire if the conduit is large enough. But if you want 240v/120v available in that panel, you would have to add 2 wires!! I said new feeder because i thought that this might be in a detached building!

Yes, usually that kind of work requires a permit but check wirh your local jurisdiction to be sure! And if u hire a licensed electrician they would be the ones who would be pulling the permit!!

 

[Socophreak]

Neutral is a grounded conductor. It is bonded to ground at your main panel. A neutral not bonded to ground is a floating neutral and can be dangerous.