How many amps are delivered to the house's main panel?

Jim Johnstone

Hi,

I have just purchased an older home (built in the late 50's), and it has had the service upgraded to 100 amp breaker panel a few years back. I would like to jump a sub panel out to the garage, but I am not sure how much amperage is actually coming to the house and how high I can go. Is there a standard for wire size coming to the house in Ontario, or does it change by region/builder?

Thanks,
Jim

jbfan

Since you have a 100 amp breker, then you have to assume that you have a 100 amp service.
Until the incoming wire size is verified, that is all you have to go on.

You will not be able to pull more than the 100 amp main breaker.

__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"

brric

You likely have upwards of 10,000 amps up to your house.

dmxtothemax

It all depends on how much power the house is drawing.
But the fact that it was upgraded,
suggests that is drawing a good amount.
But is it drawing it at the same time as the garage ?
Put in a small panel and see how it goes.
Do you have some idea as to how much power you need in the garage ?
And when you will be using it ?
If it is needed at the same time as the house is drawing a good load.
Then it is possible you will need an upgrade.

Jim Johnstone

Ok let's re-word that question. Is there a standard wire size that will be used to run from the power lines to the house? Or does that change by region/builder/age of home etc?

Ideally I'd like to put 100 amps in the garage. I can easily see myself using in excess of 60 amps at a give time, at least for short periods of time. As of right now I have a lathe, milling machine, surface grinder, shop compressor, and likely a second compressor all running on 230 volt. As well as the plans to add welding equipment in the future, and the usual 115 volt stuff along the way.

a7ecorsair

60 amps is a lot of juice for a one man shop. If you need that much power you will have to upgrade your service at the same time.

Leah Frances

Sounds like Jim might need it. We have 90 to our garage - but then again, we've got 200 at the house.

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If I could only remember to THINK about what I was doing before I did it.

Wildie

A 100 amp service will provide up to 100 amps on each leg! 2 legs X 100 amps = 200.

AllanJ

Most folks find that #6 copper wiring and 60 amps (@ 240 volts) is enough for the garage. Nothing prevents you from running #2 copper (#0 aluminum) wires and putting in a 100 amp subpanel although you cannot make use of that much power in the garage without refraining from using any power back at the main house or putting in a larger e.g. 200 amp service.

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The average homeowner who lost his house in the Oklahoma tornadoes should move for good and not rebuild. Too much complexity watchdogging the contractor. Too much a chance to be defrauded.

CDH

Here in the US it is pretty much standard for the power company to run a 2 str aluminum triplex service to most homes if the service is overhead, on larger houses with considerably more load 1/0 aluminum triplex may be used, if the service is underground usually the standard is 1/0 alum triplex and if a larger load is anticipated they may go with 4/0 alum triplex, remember every power company has their own set of standards.

jbfan

Not really. More than 100 amps and hopfully the breaker trips.
100 amps per leg is still a 100 amp service.

__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"

Jim Johnstone

Well, what I had in mind is to up the main breaker in the house panel to 150 or 200 amps, then run a 100 amp sub panel to the garage. That's why I was hoping to find out if there was a standard wire size used in Ontario from the lines to the house. I'm really hoping I don't need to get the power company to run a new line from the road to my house to facilitate the 200 amps. If I do, I'll just have to really watch how many machines I have going and tell the wife not to be running the dryer and oven too!

nap

why don't you just call the power company and ask them if the service drop is sized to carry what you need.

Jim Johnstone

Looks like that's what I'll have to do. I was hoping there was a standard size used for residential, but I guess that's not the case.

Thanks

nap

I don't know how they do things in Canada but in my area, while there is standard sizes of wires for an installation, it is not unusual to find that the service drops were never upsized when a new larger service was installed. They like to leave what is there until there is a problem and then replace it. It's just like transformers. If the one there is big enough to feed 3 houses, if a 4th house goes in, it doesn't get changed. If 5 or 6 go in, it might not get changed. That is one reason the one at the end of my line caught fire one day. It was simply overtaxed and eventually died, in smoky flames.