Wire detatched garage for 240v service.

[HellaFab]

Hey Guys/Gals,

I just bought an older home (1969 construction) with a detatched 1.5 car garage. I want to add 240v service to the garage to be able to run some larger tools off of it.

My father will be able to help me out a little more being that he has an industrial electrician ticket but I want to know what I should be expecting for setting this up.


Here are a few details:
-House has recently had the main panel upgraded to 200A.

-The garage to main panel is about 60 feet, about half of which is within the house.

-I want to do the run from the house to the garage in a trench with conduit to keep the wife happy.

-I dont forsee having a HUGE draw on the system being that the garage is only a 1.5 car. No mills or anything like that. I do however need the 240 for my TIG welder. I may or may not add at a later time a 240v compressor and wire some of my lighter duty dual input tools to 220 like my bench grinder.

-There is no sub panel in the garage at the moment as there is only one T12 light and an overhead garage door opener.



Any tips or help specific to my project would be appreciated.
Matt

 

[theoldwizard1]

Learn to use the search function of GJ. There must be 100 threads on this topic.

Be careful. Most post are for American installations. Do NOT assume Canada is the same !

 

[HellaFab]

Ok, I will search again.

fyi i have been through the first 40 pages. I know that the size is dependant on both amperage and the run length.

I was lightly treading in my OP because i wanted as many answers as possible to give a more broad view.

I need a 100 amp service run 60 feet. Once I have the panel setup I can do the interior wiring as I have in other garages/houses/cottages in the past. Those were projects that I wasnt involved in sizing the service feet for the subs and I want to understand that.

Im also not exactly familiar with wiring the subs into the panel to have an understanding on how a 4 wire system works within the panel. I know 2 hot, 1 neutral and a ground so you can run both 120 and 240 but the mechanics within the panel are beyond me at this point. My dad will undoubtedly help me out there but I would prefer to know myself both to know in the future and to seem somewhat knowledgable when talking about it with him.

Cheers,
M

 

[Zeke]

The "mechanics" within the panel are the easiest task you face. Once you size your panel with respect to what's available at the main and what you use as feeders, you will have a rating for the garage panel. Many get by with a 60A sub. With a 60A, you could probably wire in 2 20A plug circuits, a lighting circuit, and one 30A 240v circuit assuming you won't be using all of it at once, like welding with a 120v compressor running and using a 1500w heater. IOW, just because you can theoretically put 15 receptacles on a 20A circuit doesn't mean you can run several high draw appliances at once on that one circuit.

Now back to your regularly scheduled qualified electricians.

 

[HellaFab]

So I talked to a friend who is an electrician and the local electrical supply store and I think I might have come up with something.

I am going to run 100A to the garage because my TIG welder is a pretty big sucker and needs a dedicated 50A circuit. Couple that with a few 20A circuits for wall plugs and a 15 or 2 for lighting. I am also unsure if i will have a 120 or 240v compressor so that leaves a little extra space.



Like I said before, the run is about 60 feet direct, but since I need to support the wire every 3 feet by code here I will be running it along a floor joist for the indoor run. this adds another 10 or so feet since I wont be taking the hypotenuse route.

so i will be going 70 feet.


The local supply company suggested 3/3 Tek90.
Any oppinions on the #3 wire?

It was suggested to me by the supplier that #3 TEK is rated for 100A up to 100 feet (which I fall in)

 

[pattenp]

I assume it's Teck90, and #3 copper is good for 100A. See if there is an aluminum cable that they will suggest to save some $$.

 

[wrench409]

-There is no sub panel in the garage at the moment as there is only one T12 light and an overhead garage door opener.

How does the existing stuff above get's it's power if not from a sub panel of some sort?

 

[Charles (in GA)]

How does the existing stuff above get's it's power if not from a sub panel of some sort?

Most likely a single 120v circuit supplied from a single 15a or 20a breaker in the house panel.

The OP will need to disconnect and disable this circuit to prevent the garage from having two sources of power (a dangerous situation for someone working on the garage power system in the future).

Charles

 

[Zeke]

How does the existing stuff above get's it's power if not from a sub panel of some sort?

Just as mine does, I assume. A breaker in the panel that says "garage" and some wire in conduit to the garage. Many homes built that way. At this point I'm running all I have off one 20A circuit to the garage.

 

[tfi racing]

#2/3c ACWU is what you could use,copper teck is fine if you want to throw a ton of money away for no real advantage.Why don't you rely on the advice of the two"electricians" that you know,I'm sure they must be well versed on the ESA's requirements and the common local practices and materials your friendly neighbourhood inspector expects to see.

 

[rodknocker]

If you are running that much service to the garage, have you ever considered having the electric company run a box right to the garage? We can do it here, its like having a sub address and you get a seperate monthly bill just for your garage. Not sure if that would be cost effective or logical for your situation, but it is an option.

 

[wrench409]

Just as mine does, I assume. A breaker in the panel that says "garage" and some wire in conduit to the garage. Many homes built that way. At this point I'm running all I have off one 20A circuit to the garage.

The reason I ask is I assumed my garage had only 120 volts going out to it.

After reading here and other sites, I learned enough to check what to look for only to find 240 volts already present in the garage.