Thread: Bonding of raceway

In this Zinsco panel (we don't need to go into the issues of Zinsco panels here), there is a bonding strap noted that bonds the enclosure, but I see a missing screw on the nut of the lower (metal) raceway. Shouldn't that be bonded as well ?

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Before addressing that, where is the main service disconnect?

Down below that panel, or in that panel?

I would say the bushing needs to be bonded to the grounding system to bond the nipple. I don't see a locknut below the bushing so the grounding is questionable it seems from the picture.

Jerry...

No main disconnect.
Overhead service, 3/0 copper SEC, 5 throws-of-the-hand.
GEC travels from bus bar down besides raceway to earth.
Bonding wire to metal water line.

Dave,

So, the SE cable enters from the bottom?

With the other conductors? (That is not allowed.)

No, there are more than 5 mains. You have to count the blank spaces where a breaker 'could be' installed.

My guess it that that panel is not even rated 'For use as service equipment' - too many mains.

So, if not rated 'for use as service equipment' it is not allowed to be used as service equipment. If it is rated for that use, it will say so on the label.

Dick is correct about the grounding bushing, but my guess is that one is the type which also takes a terminal and screw, with the ground bond wire going through the terminal.

There are many, many things wrong with that installation, and that screw / ground terminal missing from the grounding type bushing is the least of the problems. I just touched on a the problems in there.

Thanks for all the informative feedback.
Just for "FYI" the SE cable comes in from the meter box on the left of the picture.

Dave

Dave,

Okay, I see the service entrance now.

Next question, then, where do the two SE cables go to which go out the bottom (one is copper and one is aluminum)? Range and dryer?

With all those wires in one conduit, they would need to be derated. There appears to be 6 current carrying conductors, which means derating to 80% of rated capacity.

Also, what is that extra white conductor going out the bottom for? Is this the NM cable from the 240 volt circuit in the right panel? If so, there are now 8 current carrying conductors and the derating factor drops to 70% of the rating.

Then there are those ope knock outs which should have been closed. Possibly the service equipment panel was re-used?

Then there is the circuit from the right panel which should not run back through the left panel, but, what to heck, there is room in the left panel, just install the 240 volt circuit in the left panel and do away with the right panel. Especially when replacing the left panel and making everything right.

Looks like a 240 volt circuit in the right panel with no tie handle between the two breaker (I do not see a white conductor there, was it cut off, or is it just out of view behind other conductors?).

Jerry,

You said, "Next question, then, where do the two SE cables go to which go out the bottom (one is copper and one is aluminum)? Range and dryer?"

The feeders going out the bottom are for (1) a 70-amp distribution panel, and (2) the range.

I can't speak much to the derating. That's beyond my knowledge to identify and report on.

You said, "Also, what is that extra white conductor going out the bottom for? Is this the NM cable from the 240 volt circuit in the right panel? If so, there are now 8 current carrying conductors and the derating factor drops to 70% of the rating."

The extra white is one of two conductors from a 240-v 30-amp circuit to the water heater and should be permanently marked black.

You said, "Then there are those open knock outs which should have been closed. Possibly the service equipment panel was re-used?"

Not sure what you mean about the open knockouts? The dead-front cover isn't shown in the picture and was fine for both panels in the picture.

You said, "Then there is the circuit from the right panel which should not run back through the left panel, but, what to heck, there is room in the left panel, just install the 240 volt circuit in the left panel and do away with the right panel. Especially when replacing the left panel and making everything right."

Help me understand why the circuit (black/red) shouldn't/can't run back into the left side panel?

You said, "Looks like a 240 volt circuit in the right panel with no tie handle between the two breaker (I do not see a white conductor there, was it cut off, or is it just out of view behind other conductors?)."

The circuit on the right was for dishwasher and disposal. Grounded conductor is hidden, but in there.

It is possible that the cables would not need to be derated if the length of the raceway is less that 24". I would imagine that the nipple from the LB terminates in the crawl space or basement.

Happy Easter to all!

Dick,

That does not look like an LB, it looks like an enclosure of some type. Yes, it is possible the conductors are bundled and have lack of spacing maintained, but I thought otherwise (my best guess anyway), so I brought it up.

Dave,

I asked: "Next question, then, where do the two SE cables go to which go out the bottom (one is copper and one is aluminum)? Range and dryer?"

You said: "The feeders going out the bottom are for (1) a 70-amp distribution panel, and (2) the range."

I was hoping you would not reply with something like that. That means that those are "feeders" and "feeders" (basically every type of conductor other than service entrance conductor [like in SE cable] will be the same as feeders) require the neutral conductor to be insulated.

Not 'covered', insulated. That is SE cable with an uninsulated neutral and cannot be used for anything other than service entrance conductors. At least I don't see a neutral in that cable.

~~~~~~~~~~

You said: "Not sure what you mean about the open knockouts? The dead-front cover isn't shown in the picture and was fine for both panels in the picture."

The holes in the back of the enclosure you can see the brick through.

~~~~~~~~~~~~

I said, "Then there is the circuit from the right panel which should not run back through the left panel, but, what to heck, there is room in the left panel, just install the 240 volt circuit in the left panel and do away with the right panel. Especially when replacing the left panel and making everything right."

You asked: "Help me understand why the circuit (black/red) shouldn't/can't run back into the left side panel?"

Conductors not terminating in a vertical section of a panelboard are not allowed to run through that vertical section. Not unless: 1) there is a grounded metal barrier blocking them off from the other conductors; 2) there is space "provided for that purpose", and, being as no manufacturer "provides space for that purpose", it is not allowed.

~~~~~~~~~~~~~

I said, "Looks like a 240 volt circuit in the right panel with no tie handle between the two breaker (I do not see a white conductor there, was it cut off, or is it just out of view behind other conductors?)."

You said: "The circuit on the right was for dishwasher and disposal. Grounded conductor is hidden, but in there."

If for a dishwasher and a disposal and their receptacles are on the same strap (each are one half of a duplex receptacle outlet), there needs to be a tie handle between those two breakers.

Jerry, thanks !
Educational as always.

Can you please provide an NEC reference for the insulated neutral conductor (other than SEC) requirement. I'd like to read that through and familiarize myself with it.

Dave

Dave,

"Can you please provide an NEC reference for the insulated neutral conductor (other than SEC) requirement. I'd like to read that through and familiarize myself with it."

First, follow the thought process through.

The neutral (grounded conductor) is ONLY ALLOWED to be bonded to ground AT THE SERVICE EQUIPMENT (but we all know that by now ).

Thus, the neutral (grounded conductor) MUST be insulated ... or the above is not possible. Right? How else can it be protected such that it will not become grounded at any other point along the circuit?

From the NEC. (bold and underlining are mine)
- 310.2 Conductors.
- - (A) Insulated. Conductors shall be insulated.
- - - Exception: Where covered or bare conductors are specifically permitted elsewhere in this Code.
- - - - FPN: See 250.184 for insulation of neutral conductors of a solidly grounded high-voltage system. (Jerry's note: The FPN does not apply here.)

- 230.41 Insulation of Service-Entrance Conductors.
- - Service-entrance conductors entering or on the exterior of buildings or other structures shall be insulated.
- - - Exception: A grounded conductor shall be permitted to be uninsulated as follows:
- - - - (a) Bare copper used in a raceway or part of a service cable assembly.
- - - - (b) Bare copper for direct burial where bare copper is judged to be suitable for the soil conditions.
- - - - (c) Bare copper for direct burial without regard to soil conditions where part of a cable assembly identified for underground use.
- - - - (d) Aluminum or copper-clad aluminum without individual insulation or covering where part of a cable assembly or identified for underground use in a raceway, or for direct burial. (Jerry's note: This is like the SE cable in your photo.)
- - - - (e) Bare conductors used in an auxiliary gutter.

The hole is likely there for attaching a lug, if one is needed. Absent that lug, all you have is a bushing that protects the wires from sharp edges.