House/Garage

[nosbod]

I sure takes a long time for utilities to answer a simple question. You would think if the are the supply authority, they would know what size wire they use from the transformer to their meters in a town with hundreds of houses. My best guess is the wire is aluminum and not rated at more than 125 amps which puts me at plan "B". Least expensive, but the most labor intensive, because I will have to dig another trench to the garage. It is what it is.

[foo1bar]

I sure takes a long time for utilities to answer a simple question. You would think if the are the supply authority, they would know what size wire they use from the transformer to their meters in a town with hundreds of houses. My best guess is the wire is aluminum and not rated at more than 125 amps which puts me at plan "B".

Whether it's aluminum or copper isn't really relevant. It probably is aluminum because that's usually cheaper for a given ampacity and length. Since it's cheaper and equally effective, there isn't any reason for them not to use it.

The wire to your house may or may not be capable of handling 200A. You probably can't draw any conclusions yourself, as the NEC doesn't apply to that wire - wire sizing for those wires is completely under the utility's control.

[nosbod]

What your saying is true, but if most houses have a 100 amp service with 125 amp bus then I can't see the utility bringing in a wire rated higher than 125 amps. Not cost effective.

[SunEagle]

What your saying is true, but if most houses have a 100 amp service with 125 amp bus then I can't see the utility bringing in a wire rated higher than 125 amps. Not cost effective.

You are correct. Unless you are connected to a single transformer with a high kva rating your service wires should just be 125% of your panel cb rating.

[solarix]

Utilities often plan for future growth and also for expediency. They may use all the same wire for the whole neighborhood, or just use 200A service drops because of a standard practice. You just don't know until you ask. I've done upgrades from 100 to 200A and the utility just uses the same wire, and sometimes they upgrade it...

[SunEagle]

Utilities often plan for future growth and also for expediency. They may use all the same wire for the whole neighborhood, or just use 200A service drops because of a standard practice. You just don't know until you ask. I've done upgrades from 100 to 200A and the utility just uses the same wire, and sometimes they upgrade it...

If the wire is direct burial you may be correct and it has a 200amp rating. If it is aerial it might have a lower rating. Best to ask your POCO what it is.