I have an unattached garage that I'm am planning to wire and I'd like some advice...
Run from the house to the garage is about 80 feet. I'm looking at installing a 60 amp or 100 amp service to the garage.
In the garage is an 8 breaker (16 half breaker) panel. I plan on using 15 amp breakers and 14gauge wiring for lighting and some outlets, 20 amp breakers with 12gauge wiring for several outlets, and installing one or two
220v outlets.
So, here are my questions...
- In my home, do I use a pair of 30 amp or 60 amp breakers?
- I know that I need two hots, a neutral and a ground to the garage. Would this be considered two 30 amp circuits?
- What gauge wiring should I run, considering the distance from the panel to the garage?
- Is a 220v outlet as simple as wiring two hots (each on it's own breaker, on opposite phases) and a ground, and no neutral?
- Although I'll have a small shop in my garage, are 20 amp outlets overkill?
Also, keep in mind, you'll need GFCI protection for the outlets, and NEC requires you to drive ground rods at the garage and attach them to the separated ground bar in the panel
A tiebarred breaker pair of the same ampacity that you want to deliver to the garage. If 60A, you need a dual 60A.
When you run grounding electrodes at the garage, you don't need to run a ground wire from the house.
Check with an inspector. The wire is expensive, and you may want to consider using aluminum for the feeder - as long as it's done right (proper greasing and fittings) it's perfectly safe and will save you considerable $$.
[My 100A 120' feed is #3 Al. Which saved something like $350 over #4 copper]
Yes.
Not really. Instead of doing 20A outlets (which are quite rare in Canada, because until recently you weren't permitted to put 15A outlets on 20A circuits), I used split-phase 15As. Which meant that the benchtop outlets were two 15A circuits.
Everyone keeps mentioning grounding electrodes, yet nobody I know of has had to do this. Also, there is no mention of this in the city's wiring guide.
(I'm located in Calgary, AB)
I hadn't considered this. I'll need to contact the city to find out if there are any special requirments.
Will this require special breakers in my main panel? Will I need to do anything special on the panel in the garage?
City wiring guides aren't going to cover things like this.
Get a copy of Knight's "Electrical Code Simplified", it's under $20 from most hardware or big box DIY stores. The Ontario one is Orange. Yours is Green:
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[I'm located in Ottawa ;-)]
You will most likely want to run three wire to the panel, and then install your own grounding electrodes at the garage. That's what mine has.
Trying to use the main panel's grounding is somewhat problemmatic, and is best avoided in separate outbuildings. Highly difficult with current codes to pass muster.
If you use Al wire, you have to make sure that everything it connects to is rated for Al, and grease the connections with the appropriate gunk. In my case, the electrician ran a #4 copper stub into the main panel (presumably the panel branch connectors weren't rated for Al), brought it out to a 6x6 box a foot away, and spliced it there with split bolts (properly rated for Al-Cu & grease & tape) to the Al feeder. At the garage end, the panel main connectors were rated for Al, and only need to be greased.
More fuss than straight copper, but at today's copper prices, a huge cost saving.
[I'd never use Al for regular branch circuits. For stove/panel feed circuits with proper care, yes.]
It was an ordinary 100A dual breaker in the main panel (20+ year old Sylvania Commander). At the garage end, it was a brand new 100A Siemens panel pack from HD I think.
Be aware that 60A and 100A dual branch breakers for older panels have become somewhat rare and are often pricy beasties. I lucked out with the 100A, the electrician gave it to me out of his junk box for free. The last 30A Commander dual I had to buy was ~$80. Once you see how much one costs new (if one is available at all), you might consider visiting flea markets. They often have whole panels you can cannibalize for their breakers.
Theoretically, you only need a breaker on one end of the subfeed, but, I don't like omitting the breaker on the main, and a "panel pack" with main breaker is cheaper than piecing it together without one.
[While I do/did almost all of this wiring myself, the panel feed itself I had done by an electrician because a minor goofup can be hugely expensive. He was a friend, and he did it cheap ;-)]
Sorry, didn't realize your location. In the US if you run more than two 20 amp circuits to a detached garage, you're required to install ground rods. By current code you're not required to run a ground with the feeder, however if you don't, you can't run anything conductive between the garage and the feed building, such as water line, telephone, etc.
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