question on power to detached garage

[laser3kw]

I have been reading all the great advice on here for a while. I thought I had a pretty good understanding of what it takes to run power to a detached garage.
I have a new detached garage that I need to get power to. It is about 75 feet from the panel in the house. The house panel is a 100 amp panel, the house is very small and doesn't draw much.
I had a local electrical service come out to quote running the power out to the garage. To my surprise, he said all I needed was a 100 amp breaker on the existing house panel and trench the wires to the garage and use load center with a master breaker (not sure if that's the right term) out there for the garage hookups. I hate to question it, but he said that it would be no problem. He will pull the permit and the job would be inspected. His firm is licensed and insured so I guess everything should be on the up and up.
Any advice?

 

[Gary S]

It sounds like he knows what he is doing.

 

[pattenp]

Get more than one estimate. And make sure the estimates can be compared apples to apples.

 

[soob]

They don't call it a 100A panel for nothing. Obviously you can't use 100A in the house and 100A in the garage at the same time. Frankly I have no idea whether that's code or not though.

But most of the cost is going to be labor, so you'd be nuts to put anything less than 100A in the garage. You can always upgrade the main panel later if necessary.

 

[CNGsaves]

I'd recommend upgrading your overall service to house to 200 amp, and then run 100 amp to the detached garage. Thus, main panel in house likely needs upgraded.

If you'll ever consider a whole-house generator, now is the time to plan for that (ie either with ATS or interlock).

While you're trenching to detached garage, put in extra conduits for telco, cable, internet, etc.

Good luck. Best results come from the best made plans!!

 

[dave67fd]

Depending on how close you are to the street, can you get a direct service to the pole? Only cost me a small fee to get a technician to evaluate. Most towns have a distance allowance and won't cost you a dime if run within the allowance. Just something to think about if you haven't already.

 

[VHF]

I concur that the solution proposed to you is probably appropriate for your situation, and there is no problem code-wise with running a 100A subpanel off a 100A main.

You can always upgrade the house service to 200A in the future if needed.

 

[Stuart in MN]

I concur that the solution proposed to you is probably appropriate for your situation, and there is no problem code-wise with running a 100A subpanel off a 100A main.

You can always upgrade the house service to 200A in the future if needed.

The only thing I would add is you need to make sure your existing 100 amp main panel can accept a 100 amp branch circuit breaker.

 

[Aceman]

The only thing I would add is you need to make sure your existing 100 amp main panel can accept a 100 amp branch circuit breaker.

Or see if subfeed lugs are available.

In either case, if you use a qualified electrician he'll take care of the details like that.

 

[laser3kw]

Thanks for the input. I feel more comfortable with his assessment now.
I did research a variety of alternatives. I did ALOT of reading here first. That is why I was surprised at the KISS solution he offered.
I had Com Ed come out and we went over a variety of things. The building is to far off the street for a direct drop. I could trench to the pole and they will connect for $1700 plus I would have to pay for trenching and approx 200 ft of direct burial for 200amp. I can up grade the house service to 200 amp, Com Ed will upgrade for free, I will have to pay to upgrade from the weatherhead connection down to the panel, upgrade the panel to 200amp, then trench to the building, 75' direct burial, plus a panel for the building. I also could "double lug" "double tap" the meter connection, but I would need an outside disconnect for the service split ( may not have explained this exactly right)
The contractor pointed out the obvious, run the 100 amp breaker off the existing panel and if needed upgrade to 200 amp later.
Now here is the next question.
If I do the 100 amp off the main, should I bury cable big enough for 100 amp or, bury larger cable for a future 200 amp service.
Or can I run a 200 amp sub off a 200 amp panel?

The possibilities are mind boggling!
IDK, sometimes I over think things too much.....

 

[pattenp]

If your garage is a typical DIY work space then I see no need for 200A service. The 100A will most likely be all you need. What do you plan on doing in the future that would make you consider 200A.

 

[laser3kw]

If your garage is a typical DIY work space then I see no need for 200A service. The 100A will most likely be all you need. What do you plan on doing in the future that would make you consider 200A.

I know, I know.
Like I said, I over think things to much. Or dream big.
But thanks for steering back to earth. The only "big draw" items I for see would be:
220v mig and / or tig welder,
maybe upgrade to a 220 v air compressor
2 post lift.
I realize the likely hood of drawing "to much" is remote. I can only operate one item at a time.
But I rather ask questions now then having to "re do" later.
So what size cable should I bury (in conduit) for 100amp, 75 feet? MHF? Aluminum, Copper?
Thanks again

 

[pattenp]

#1 Aluminum can be used for 100A. Aluminum is the cheapest way to go. IMHO is to use 2-2-2-4 Mobile Home Feeder if available and put it on a 90A breaker in the house main panel and use a 100A main breaker panel in the garage.

 

[laser3kw]

sincere thanks Pattenp and others. I now have a direction to follow. I am waiting for the quote from the contractor. I get the feeling he is not real interested in this job. I am interested to see if he quotes something close to what has been suggested here.
Until then, I will keep reading until "the code" becomes a little clearer.