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About PASCACK VALLEY ELECTRIC Bob Mossman
Expertise
Licensed Master Electrician (29 years) 6165B Contractor in Closter New Jersey with 38 years total experience in Residential - Commercial - Industrial work. Emergency Service - General trouble shooting and repair work - Paddle fans - Kitchen & Bath exhaust fans - AC lines - Smoke detectors - Telephone lines - Cable TV lines - Computer network cabling - Exterior lighting - Recessed lighting - Security lighting - (200 - 150 - 100 amp service up grades) - Electric Heat - New circuits - New appliance hook ups - Back up generators - and more ! FREE ESTIMATES 201-358-1552 www.pascackvalleyelectric.com
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Experience
Licensed contractor in Closter New Jersey.
Education/Credentials
"The Frank Williams School of Electrical Construction". My dear old boss is 96 and still going God Bless him. I started working for "Tenafly Electric" right out of high school at 19. He was tough but I learned more working for him in 8 and half years than most guys. We did mostly industrial work while doing some commercial and residential so I was fortunate to be exposed to all 3 areas of electrical construction. The guys I worked with were all good guys and I stay in touch with some of them still. Most of us went into our own buisness's which says something about the caliber of the guys I worked with. We had some interesting clients : Wella Corp. of shampoo fame, Farah Fawcett etc, I didn't buy shampoo for 10 years, it was a great place to work. Pan Am the X airline just before they went under, another great place to work, nice clean environment. C&C Metals, the largest button manufacturer in the US, a not so clean environment but a very interesting place to work, lots of machine's cranking out buttons of all kinds but you had to be on your toes, it was a potentially dangerous place to be . All kinds of action going on around you.
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You are here: Experts > Home/Garden > Home Improvement/Repair > Electrical Wiring in the Home > Electric to detached shed.
Expert: PASCACK VALLEY ELECTRIC Bob Mossman - 11/8/2009
Question
Hello...
I am running electric out to my detached shed, and have a couple of questions.
Here are the details:
200 amp panel in my house
80 feet total distance from house breaker panel to shed breaker panel
#10 three conductor + ground UF cable already run in 24" deep trench and passed inspection (not filled back in yet)
Initially, I wanted to only run 120 out to the shed, but after talking to the inspector, he said I could run 220 out there since I had three wires.
My questions are:
1. What is the largest breaker I can put in the house panel? I assume I can use a 30A, 2 pole breaker.
2. What size load center can I use as the subpanel? Can I use a 100A, but put a 30A main breaker in it?
3. I am reading conflicting information as to whether or not I need to install ground rods next to the shed. Some places say use the bare ground from the house, some say install a ground field. Which is correct?
4. The inspector said something about 'backwiring the breakers' to get 220. I can't find any information on what he meant. The only thing I could find that mentioned any kind of special wiring at the subpanel said you had to install a separate grounding kit so that the neutral and ground were not together.
Thank you in advance for your advice on this.
Steve
Answer
Steve,
1. 30 amp 2 pole.
2. You could use a 12 circuit 100 amp sub panel which sould be plenty and give you plenty of room to work as opposed to a smaller panel but remember you only have 30 amps to work with on all 12 circuits. In other words you couldn't operate any combination of circuits simlutaneously that will exceed 30 amps with out blowing the breaker so just keep that in mind. Yes you can put a 30 amp main in it and I would advise you to do that so you can kill the entire panel with out going back into the house or have someone turn the power on when your working on the panel.
3. If the sub panel was located some where inside your house you would not need a separate ground rod for the sub panel. If you install the sub panel in a separate structure that is detached from your house such as your shed the code requires a separate ground rod for the sub panel.
4. The inspector was probably refering to this: If you put a 30 amp breaker in the sub panel as your "Main breaker" you will be bringing the power into the breaker on the terminals where the power normally goes out, hence "back wiring" the breaker. In other words when you install the other breakers in your panel for your new circuits the power will be going out on those terminals, where as the # 10 black and red wire from the UF cable will terminate on the terminals of the 30 amp 2 pole breaker but the power is going into the breaker at that point not out of it as it does on the other breakers.
You must also install a separate "grounding bar" kit, (terminal strip) which is an accessory to the panel. It bolts directly to the panel. There you will connect all your bare ground wires and green ground wires. You will also connect the #6 copper ground wire from the ground rod to this terminal as well as the bare # 10 ground wire in the UF cable. All your white wires will go to the neutral block (terminal block) that comes standard with the panel. You will not connect the neutral block to the grounding terminal VIA jumper (wire) or bonding screw that comes with the panel. Each is a separate area in a sub panel unlike your main panel where it is Ok to terminate the bare grounds, and green wires with the white wires on the neutral block (terminal block).
Enjoy your project.
Bob
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