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Sir Sparks
Sir Sparks, President/Owner/ Master Electrician
Category: Electrical
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Experience:  US State Certified & UK Electrical Contractor for all electrical fields/disciplines
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I want to run a 30 Amp / 120 volt line to my utility shed from

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I want to run a 30 Amp / 120 volt line to my utility shed from my house electrical panel. What size wire do I need to purchase? I want to operate power tools and also put in an outlet for my travel trailer from the same circuit that will allow me to run the airconditioner.

Can I purchase a 120V 30 Amp Breaker or do I have do use a 240V Breaker? (It is a square D 200 Amp entrance)

Hi. I will need to know the distance to give you a wire size.


You don't need to run 240 volt but the wire size will be smaller so usually it will be better to do so.

Customer: replied 6 years ago.
Unfortunately the house entrance is on the opposite end of the house from the shed so it is about 80 ft from the house entrance to the Shed

80 ft is OK and won't change wire size.


You need #10 copper. but you MUST run a ground and install a local ground rod at the shed.


So either 2 wire plus ground for 120 volts or 3 wire plus ground for 240 volts. I recommend a small 4 circuit sub panel ($10) then a driven ground rod connected to the ground bar. The ground bar is ADDITIONAL to the neutral bar and should have only ground wires attached to it. NOT as it is wired in your main panel.

I do recommend 240 volts for the small additional cost
Customer: replied 6 years ago.

So does this sound correct?:


  • Add a 30A /240V breaker to my Home entrance.
  • connect 3 conductor plus ground #10 wire to this breaker
  • run this wire to my shed (through underground conduit for the last 15 feet)
  • connect to a 4 cct subpanel at the shed.
  • add a 15 A breaker for lights, seperate 15 A breaker for outlets.
  • Add a 30 A 120V breaker for my travel trailer outlet

am I forgetting anything?




Perfect except don't forget the driven ground rod connected the ground bar at the shed. The ground bar does not come with the sub-panel so you will need to purchase it seperately (about $6) Put the two 15 amp breakers on one leg and the 30 amp on the other leg.
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