House/Garage

[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.

[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]

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.

[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.

[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]

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 haven't heard back from Fortis yet, but I do have a contingency plan if I can't put in a 200 amp panel. I will come off the meter and put a splitter before the 100 amp panel and then come off the splitter to a 20 amp disconnect to feed the garage inverter. Same type of thing as a line tap.

Not just the same type of thing - what you're describing *is* a line side tap.

[nosbod]

I haven't heard back from Fortis yet, but I do have a contingency plan if I can't put in a 200 amp panel. I will come off the meter and put a splitter before the 100 amp panel and then come off the splitter to a 20 amp disconnect to feed the garage inverter. Same type of thing as a line tap.

[Ampster]

......I am hoping I can upgrade to 150 amps, if so I will buy a 200 amp panel and replace the main breaker with 150 which will give me 100 amps back feed. The problem being, the 200 amp panel will be $260.00 bucks and to replace the breaker, another 200 to 400 depending whether I go with the 10K or the 25K rated breaker. Spending 1000 bucks to replace my panel is a cheap price to pay so I can put in another 4.5 K system on top of my 9.2. With the price of hydro in Alberta which has got from 8 cents to 13 cents a kilowatt, the 1000 bucks will be recouped in 6 months.

That was my fallback plan when I upgraded from a 100 Amp service panel. Fortunately no transformer upgrade was needed for 200 Amp service and the new service drop was only $75 from PGE.I did spend the extra bucks for a panel with a 225 Amp bus to give me flexibility in terms up future upgrades.

[nosbod]

I'm waiting to hear from the utility to find out what size wire is run from the transformer to the meter. I am hoping I can upgrade to 150 amps, if so I will buy a 200 amp panel and replace the main breaker with 150 which will give me 100 amps back feed. The problem being, the 200 amp panel will be $260.00 bucks and to replace the breaker, another 200 to 400 depending whether I go with the 10K or the 25K rated breaker. Spending 1000 bucks to replace my panel is a cheap price to pay so I can put in another 4.5 K system on top of my 9.2. With the price of hydro in Alberta which has got from 8 cents to 13 cents a kilowatt, the 1000 bucks will be recouped in 6 months.

[Ampster]

And now there are material shortages to deal with. I recently had to pay list price for a Solar ready 200 Amp panel because only one local supplier had the model I needed.

[SunEagle]

There seems to be some disparity between the US and Canada. My 60 amp panel in the garage and the 100 amp panel in my house both have 125 amp bus, and the last 200 amp service I installed 10 years ago had a 225 amp bus. So it seems there is some differences. The last 100 amp panel I installed 2 years ago, and I picked it up in the US, had a 125 amp bus.

It really depends on the panel manufacturer. Some of the home style type panels (like Bryant) do not have the higher bus rating but if you look at the commercial panels (like Square D) they are rated higher and unfortunately also cost more.

[nosbod]

There seems to be some disparity between the US and Canada. My 60 amp panel in the garage and the 100 amp panel in my house both have 125 amp bus, and the last 200 amp service I installed 10 years ago had a 225 amp bus. So it seems there is some differences. The last 100 amp panel I installed 2 years ago, and I picked it up in the US, had a 125 amp bus.

[foo1bar]

but a 200amp panel with a 200 amp main breaker has a bus rated at 225amps.

That wasn't true with my 200A panel. It's a 200A main breaker and a 200A bus bar.
And it's not that mine is an old panel nor an unusual one.

[solarix]

99%+ of all 200Amp panels have a 200A buss. 225A "solar ready" panels are a new option that few homebuilders use (except in California where solar ready is now mandated for new construction). Yes, by all means if you are building homes - put in a solar ready electric panel.
btw, 225 x 20% = 45, 45 + (225 - 200) = 70A.