Code Challenge

[neal]

One owner with 2 com. buildings on same lot. Building A has single phase service. Building B has 3 phase service. Contractor runs a 3 phase feeder from building B to building A for a machine hook up.

1) Do you have to group disconnects when 1 is a service and the other is a feeder?

2) If you do not group disconnects do they have to be labeled more than 1 power source to a building?

3) Do you agree feeder ground has to tie to ground at building A?

Please list code sections to help me and other inspectors agree.

 

[eprice]

1) 225.34 requires the two to six disconnects for each supply to be grouped, but I don't think it requires the disconnects for both supplies to be in the same location. In fact, 225.37 implies that they can be located in different locations.

2) 225.37 requires a plaque at each location denoting the other supply or supplies to the building.

3) If you mean should the feeder equipment ground be connected to the building grounding electrode system, then yes. 250.32 along with 250.58 require it.

 

[George Stolz]

I agree with Eprice. I have two questions about this installation.

1. What size is required for the GEC from the 3? feeder to Bldg B's GE?

2. Will this GEC experience objectionable current (from the single phase service to the 3? feeder EGC, to the 3? service...), perhaps allowing it to be omitted per 250.6(B)?

 

[Pierre C Belarge]

") Do you agree feeder ground has to tie to ground at building A? "



250.32(A)exception
foregoes the need for a grounding electrode for one circuit, of which the OP is installing.

bonding the two systems together???

250.58 says " Where separate services, feeders, or branch circuits supply a building and are required to be connected to a grounding electrode(s), the same grounding electrode(s) shall be used."

With regards to this section, I do not see the need to connect this to the grounding electrode.

 

[iwire]

") Do you agree feeder ground has to tie to ground at building A? "



250.32(A)exception
foregoes the need for a grounding electrode for one circuit, of which the OP is installing.

The OP describes a feeder not a branch circuit.

As it is a feeder it requires grounding electrode(s).

The grounding electrodes are required to be 'common'.