I am planning on installing a 60 amp sub panel in my detached garage. Originally I was going to run (3) #6 THWN feeders with a #8 ground, buried in conduit. The total distance from main panel to sub panel is about 160 feet.
After using a voltage drop calculator at southwire, it is saying my voltage drop is going to be 6%+ using this wire.
1) At what percent of voltage drop should I try to stay under?
2) Southwire calc is recommending #2 THWN or #2/0 Aluminum for my feeder, does this sound about right?
Thanks Speedy... Right now, I'm only planning on using overhead lights and a space heater. This will be used for storage of products for my home based business. When I finally decide to use it as regular garage, I will have more load from the typical tools such as a table saw, compressor, etc... I'm not real sure what calculated load I should be going for. Any thoughts?
Andrew79, that's what I thought too... I'm trying to avoid going up to #4 THWN if possible because of price, but if that's what is needed then I guess I have to...
Speedy's most likely right with the number 4 I would think. Still smaller than 2 so should save you some coin.
It depends on your heater. You can really only have one or two tools running at the same time so the wattage of your heater will determine your service size for the most part.
Garage is only 300 sq ft, not sure if that affects anything... I guess I could drop my breaker size down to 40 amp, but not sure if that would be enough in the future or not?
I just priced the 2/0 (w/ground) and it's much cheaper than the copper... I think I will go this route. At 160 ft, what size breaker should I go with that is rated for 2/0 connections?
Just to clarify my question, at what breaker size should I go with (that is rated for 2/0 connections) that will keep my voltage drop at an acceptable level?
Oh, there you go. I didn't know this because I've never wanted to do it, but you cannot use type SE cable underground.
338.12 Uses Not Permitted.
(A) Service-Entrance Cable. Service-entrance cable (SE)
shall not be used under the following conditions or in the
following locations:
(1) Where subject to physical damage unless protected in
accordance with 230.50(A) (2) Underground with or without a raceway
(3) For exterior branch circuits and feeder wiring unless
the installation complies with the provisions of Part I of
Article 225 and is supported in accordance with 334.30
or is used as messenger-supported wiring as permitted
in Part II of Article 396
If I was to just do a new 100 amp service on this detached garage instead of running a sub panel to it, is installing a new service for garages pretty much the same (code wise) as residential installs?
To do a sub panel it will cost me $900 in materials + $170 to rent the trencher.
To do a new service, it will only cost me about $350 including insp fees.
Yeah, it is $5.00 per month. Even at 12 years later, the monthly meter fee + the new service cost would finally equal the same cost as running a sub panel. Plus I wouldn't have to tear up the yard and I would have 100 amps at garage, instead of 60
I'm just not sure if there any additional code requirements for doing a new service in a garage vs a house.
A drop of 6% is not going to worry most overhead lights,
Neither is it going to effect a space heater to any large degree.
However things like table saws and compressors are likely to
be effected more than the lights.
Most motors require a large start up surge,
This is where you might have problems.
For long term compatability use the largest wire
you can afford, this will minimise any problems.
Some power companies will not allow two services at the same address. If they do the second meter is billed at a commercial rate for consumption.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
DIY Home Improvement Forum
3.1M posts
319.6K members
Since 2003
A forum community dedicated to Do it yourself-ers and home improvement enthusiasts. Come join the discussion about tools, projects, builds, styles, scales, reviews, accessories, classifieds, and more! Helping You to Do It Yourself!