Panel Upgrade

[tlnorco2003]

I have a neighbor that has a 100 amp Zinsco panel. He wants to upgrade to a new 200 amp panel. I know I have to use 2/0 wire up through the weatherhead for the 200 amps. My question is, The utility company's wire size appears to be either #1 or 1/0 wire. Is that wire sizing on their side enough for the 200 amps? I was told here in California that (SoCal Edison) the utility company only needs to use #1. Any feedback would be appreciated.

[Jim Katen]

Originally posted by tlnorco2003

I have a neighbor that has a 100 amp Zinsco panel. He wants to upgrade to a new 200 amp panel. I know I have to use 2/0 wire up through the weatherhead for the 200 amps. My question is, The utility company's wire size appears to be either #1 or 1/0 wire. Is that wire sizing on their side enough for the 200 amps? I was told here in California that (SoCal Edison) the utility company only needs to use #1. Any feedback would be appreciated.

Conductors in open air have a higher ampacity than you're accustomed to seeing. The utility company will have its own method of determining the correct sizing of the service drop wires.

- Jim Katen, Oregon

[tlnorco2003]

Originally posted by Jim Katen

Originally posted by tlnorco2003

I have a neighbor that has a 100 amp Zinsco panel. He wants to upgrade to a new 200 amp panel. I know I have to use 2/0 wire up through the weatherhead for the 200 amps. My question is, The utility company's wire size appears to be either #1 or 1/0 wire. Is that wire sizing on their side enough for the 200 amps? I was told here in California that (SoCal Edison) the utility company only needs to use #1. Any feedback would be appreciated.

Conductors in open air have a higher ampacity than you're accustomed to seeing. The utility company will have its own method of determining the correct sizing of the service drop wires.

- Jim Katen, Oregon

so i'll have to check with them to see if the current wire is suitable.

thanks for the feedback. Jim

[Chad Fabry]

current wire

You punsters just kill me

[Jeff Remas]

Normally as part of the permit process, you will have to contact the utility company and request a job number after you tell them what they are doing. Sometimes they have you relocate the service (this has happened to me more than once) so don't think you automatically will be placing it in the same place as the existing service.

The utility company uses very specialized wire with a much higher amperage rating than what it looks like it can carry.

I noticed you said you would be OK with 2/0 but you did not specify copper or aluminum which is a key factor. In addition, I can assume that this is a residence and not a business or commercial property which includes 3unit apartment houses and up. How you run the wire, (conduit, SEU, etc.) may also have an effect on the amp rating of the service entrance cable.