I built a new workshed to be mainly used for carpentry and fixing things. I have a 3' x 6' workbench. The shed is 10' x 12'. I will be running power tools. I need instructions on on installing the breakers and running the wire underground to the shed, and what I will need to do in the shed. What materials will I need? ( I was told (2) 20 amp breakers would be needed.) I want to have enough outlets (maybe a power strip with multiple outlets) to have several tools plugged in at the same time. I have 4 open spaces in the circuit box fror new breakers.2 are adjacent to each other ( # 18 and # 20)

From your questions I'm going to infer that you have little to no experience with electrical work. Have you read or do you have books on residential wiring?

I strongly suggest that you contact several licensed electricians to bid on this work.

Before any work can be completed a load study must be done to determine what the expected load demand will be needed to properly feed the shop. A qualified electrician is the best for this.

Next you need to contact your LAHJ to get a permit for this job. In order to get the permit, you may be required to provide a detailed plan for the electrical work.

Some of the actual work will involve installing a sup-panel feed into the main service panel. The main service panel can be a very deadly place.

You also have to know what size breaker to use in the main panel. The size and type of cable (must be 4 wire). The gauge of the wire is dependent on the amperage needed for the shed and the distance to the shed.

Next are you going to run the cable in conduit or direct bury? Either way, the trench must be dug so that either the top of the cable or the conduit must be at least 18" below top grade.

If you direct bury the cable then there are specific cable types that must be used.


Now you have to install the correct type of sub-panel. You must make sure that the Neutral and Ground connections are isolated from each other. The sub-panel must be properly connect to an earth-ground system.

The list just keeps building from here.

The final part is the inspection. When the work has been completed, the work has to be inspected by the LAHJ.

I am kind of with Don on this one.

Are you looking for every detail on how to do this and all the material involved?
If so this is a pretty tall order and you may be getting in over your head. This is not a simple little project.

Dependent upon soil conditions and the distance to the shed, the toughest part of this job may be the trench to the shed. For direct burial cable the depth is 24 inches, for nonmetallic conduit (pvc) 18 inches and for ridgid metallic conduit 6 inches. Since the depth is only 6 inches I generally go for ridgid metallic though the materials are the most costly. I generally avoid direct burial because to repair a damage to the wire is a lot of work. A 30 amp 240 volt subpanel will likely provide you with plenty of power at a fair cost. It give you 7200 watts. If you allot 200 watts for lighting you have 7000 watts left. A saw drawing 15 amps is using 1800 watts.
As far as doing the actual work- The first question is, is it allowed? Ask at the building dept. Even if it is allowed I would think this is a ambitious first project. Maybe you could find an electrician who would work with you, you dig the trench pull wires etc, and he does the connections. There is a lot of detail work in a job like this. Enthusiam is no substitute for experience.

Herman,

You raise a decent issue. Here in Virginia Beach, VA the LAHJ requires 18" from the top of either the conduit or cable to finished grade. Obviously your area is quite different.

Equally obvious would be the requirement to either check with the LHAJ or an electrician for the trench depth required for a cable trench in the OP's area.

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Originally Posted by hermanwachs

Enthusiam is no substitute for experiance.

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I love this line! :D