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



## Jim Johnstone (Mar 15, 2011)

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 (Jul 1, 2004)

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.


----------



## brric (Mar 5, 2010)

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


----------



## dmxtothemax (Oct 26, 2010)

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 (Mar 15, 2011)

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 (Jun 1, 2010)

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 (Jan 13, 2008)

a7ecorsair said:


> 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.


:yes:

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


----------



## Wildie (Jul 23, 2008)

jbfan said:


> 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.


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


----------



## AllanJ (Nov 24, 2007)

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.


----------



## CDH (Aug 8, 2009)

Jim Johnstone said:


> 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.


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 (Jul 1, 2004)

Wildie said:


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


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


----------



## Jim Johnstone (Mar 15, 2011)

AllanJ said:


> 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.


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 (Dec 4, 2007)

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 (Mar 15, 2011)

nap said:


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


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 (Dec 4, 2007)

Jim Johnstone said:


> 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


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.


----------



## AllanJ (Nov 24, 2007)

nap said:


> I. It's just like transformers. If the one there is big enough to feed 3 houses, ... 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.


There should have been a fuse up on the pole next to the transformer.


Jim Johnstone said:


> 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. :


While a #2 copper (or #0 aluminum) line is needed for 100 amps coming into your house, the portion strung through the air, say from a utility pole can carry somewhat more without overheating. How well it performs (how much voltage drop you get when drawing 150 to 200 amps) depends on the distance. There are usually two wire sizes for 120/240 volts (secondary lines) up on the poles, a larger size between poles and a smaller size for the service drops to the houses.

When you put in the 200 amp panel you will replace the wires from the meter to the panel. I think it is OO copper or OOO aluminum you need.

If you want to you can just go ahead with your project. Then if you do get too much voltage drop, put in a complaint to the power company.


----------



## Jim Johnstone (Mar 15, 2011)

Is it possible to purchase the new 150 or 200 amp main breaker for my existing panel, or would I have to buy a panel that has the right size main breaker already in place?

Jim


----------



## a7ecorsair (Jun 1, 2010)

Your panel will have a label stating its capacity. What does your panel have on this label?


----------



## Jim Johnstone (Mar 15, 2011)

a7ecorsair said:


> Your panel will have a label stating its capacity. What does your panel have on this label?


 
That I will have to check once I move in. I am just trying to start planning things out for this summer, since I'd really like to have my shop up and running asap.


----------



## nap (Dec 4, 2007)

> AllanJ;610430]There should have been a fuse up on the pole next to the transformer.


yep, sure was. It allowed to x-former to heat up pretty good and catch fire.


----------



## Wildie (Jul 23, 2008)

nap said:


> 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.


 Its the same here in Ontario. Our engineers go to school for seven years and then sit in an office copying whatever is done in Michigan. :wink:


----------



## LyonsElecSupply (Jun 16, 2010)

(This is the US standard)

The problem I see with this is 

1. that his Meter Base needs to be rated for 150 or 200 amps. 
2. His current panel MORE THAN LIKELY will not be able to have a 150 or 200 amp breaker "just dropped into it" 150 and 200 generally are molded case breakers
3. 4/0 Alum is the service size for 200 and 2/0 alum is service for 150. (dont go with copper is it god awful expensive)
4. His overhead is of no concern, as I was told by a POCO guy: "we dont have to abide by the NEC." Whether this is true or not is up to debate, but what i do know is that overhead, free air conductors can carry MUCH more current than service conductors..generally about 50% more...or so...
5. If you do work on the meter base, you will probably have to pull a permit to have it reconnected to the meter....

Bottom line, you can either install it next to your drop and have them switch it over, or you will have to have the knife or your service drop pulled and put back in which requires a POCO and a Permit.

Good luck partner.


----------



## Jim Johnstone (Mar 15, 2011)

Turns out I may be ahead of the game. I was under the impression that the garage just had a couple of 15 amp 110 volt circuits run from the house, but as luck would have it, the fellow I'm buying the house from worked for Ontario Hydro for years, and put 220 volt in the garage. I had a real quick look at the subpanel in the garage, it's an older screw in fuse style, but looks like it has at least 3 gauge wire running to it. Once I get a chance I'll look at how he attached it from the house.


----------

