100amp service to detached work shop?
Question:I currently have a 200 amp service to my house. I want to run a 100amp service out to what is really just a very large shed I want to convert to a work shop.
1. At 150 ft from panel to subpanel, Is it suitable to run 4\2 aluminum as allowed by table 310.15(B) (6)?
2. I had orignally planned on just putting a 100amp 2pole breaker in my main panel and running it out to my workshop. The panel is very full however. I allready have 3-4 of the 2pole idividually switched breakers. In order to fit my new 100 breaker I would have to pull out 4 of the single pole breakers and add 2 of the 2pole idividual switched breakers and my 100amp 2pole for my new service. When do I have to worry about too many circuits coming from the main panel?
Answers:
You should be running #2 alum. or #4 copper SER cable (this wire has 2 hots neutral, and ground wire).In the sub panel you need to keep the ground bar and neutral bar seprate and you also need to drive a ground rod out at the shed because it is detached from the house.
You want to have the sub breaker in the main panel , you should be able to use tandum breakers (breakers that you can put 2 circuits on and takes only the space of one) to free up more space . Usually in the panel it will tell you how many circuits you can have , usually a 200 is around 40 max but if you go a few over I would not worry. Worst case you could put a small sub panel next to the main and pull some circuits from the main to the sub to free up space
Your service should be up-graded by a pro, you are in for problems.
If I were doing it, and have in the past. I would install a second switched box next to the main panel. Run underground and in conduit to a switch box in the shed with low amp breakers. Do the shed wiring first, then tie in the rest as you come back to the power source.
You should be able to tie into the mains after they send power to the main board and before other breakers.
This will give you normal house protection and still have the house mains to send power to the shed where you have provided mains to run the shed from.
You need a switch at the house to break power to the shed, and breakers to protect the long wire which is going to drop your available amps considerably.
Example send 15 amps to the shed. Usable amps may be 10 or less. IE breaker will not break. To test, use several heaters in parallel for load. Measure currant draw at house box......NEVER NEVER NEVER use aluminum wiring. It's dangerous...... left to an expert, but this will work if done correctly.
Wireing from house to shed should be 000. I got away with range wireing do to low amps needed, but you must double wire to do it and no one will ok that as safe.
Again, if you don't know what your doing, dont!!!!!!!
It looks like you will require a temporary disconnect from the main feeder. You will also likely require a licensed electrician and a permit. The electrician will fill you in regarding the ugly details, so make it easy on yourself and call a recommended local to ease your mind about the calculations and execution of your project. There. That makes it easy doesn't it? Done.
I agree with the above answer as the best method.
Your method will also work depending on what the load is for your house. If you have multiple AC and hot water, pumps pool equipment you may already be close to maximum. How many things will run at the same time in the work shop? Some lights a vacuum and a saw. It may not be a problem to use your method and #4 copper wires should be sufficient with your method. 3- #4's and a #6 ground (you can down size the ground wire).
He suggests the 000 because he is assuming that is the size feeding your main at this time and you must use the same size wire until it passes through a breaker.
I would not suggest using aluminum wire.
should have 42 circuits max in main panel
you need to use table 310.16 because it is a sub panel.
#1 using the 75 degree column might be a good idea to increase size to 1/0 because of distance
if you run 4 conductors out and seperate ground and netural use #4 al ground.
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