Two Feeders on One OCPD

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Mike Furnish

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Houston, TX
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I have a very old service That has a fused disconnect (400A Fuses). There are two feeders terminated on the load side of the fused disconnect switch. Each feeder goes to a separate building. One feeder is #4 THHN and the other is #1/) or #2/) cloth wiring (not sure what the actual size is since I can't find any writing on the cloth). My question is, are these feeders considered tap conductors? Is it legal (NEC) to have multi feeders on the same OCPD and if it is, how do I size the OCPD?
 
Yes it is legal to have more than one set of conductors connected to the same OCPD. Since the conductors you named do not have sufficient ampacity to be protected by a 400 amp fused disconnect, they are considered tap conductors. The important question is whether they comply with at least one of the tap rules provided in 240.21. That would depend on such things as the OCPD at the termination of the conductors, the length of the conductors, and whether they are protected against physical damage. You would need to tell us about these things, in order for us to have an opinion on whether your installation is legal.

Welcome to the forum.
 
charlie b said:
Yes it is legal to have more than one set of conductors connected to the same OCPD. Since the conductors you named do not have sufficient ampacity to be protected by a 400 amp fused disconnect, they are considered tap conductors. The important question is whether they comply with at least one of the tap rules provided in 240.21. That would depend on such things as the OCPD at the termination of the conductors, the length of the conductors, and whether they are protected against physical damage. You would need to tell us about these things, in order for us to have an opinion on whether your installation is legal.

Welcome to the forum.
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Well put.

I'd also be curious as to whether or not the 2 conductors are under the same or separate lugs.

JAP>
 
jap said:
Well put.

I'd also be curious as to whether or not the 2 conductors are under the same or separate lugs.

JAP>
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Did the one wire per terminal rule apply when cloth covered wire was used?

It appears to me to be a situation where the two feeders are tap conductors. Who knows what rules were in place when the install was done.

Personally I would be looking at gutting and redoing such an install.
 
My reply:
Two separate lugs are used to terminate the conductors at the fused disconnect switch. Both feeders are longer than 100'. One feeder (#4 THHN) is underground in a conduit to the building, while the other feeder (#1/0 or #2/0 Cloth) goes up the pole supporting the fused disconnect switch and then overhead twisted secondary (250') to another building. The twisted secondary is #1/0.
 
I just looked at the pictures and this is a 120/240V, 4W (closed delta) service. The cloth covered wire is terminated in one lug (1 conductor per phase) and there are two #4 THHN conductors terminated for each of the 120V legs on a single lug and one #4 THHN terminated in a lug for the high leg.
 
petersonra said:
Did the one wire per terminal rule apply when cloth covered wire was used?

It appears to me to be a situation where the two feeders are tap conductors. Who knows what rules were in place when the install was done.

Personally I would be looking at gutting and redoing such an install.
Click to expand...

Good point.

May not have.

JAP>
 
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