AboutMaster Bob Expertise Master Electrician / Owner RKO Electric (USA Only) - can answer most of the typical residential, commercial and industrial electrical questions regarding new installations, wiring additions, lighting, switches and receptacle outlets and electrical upgrades of any nature.I will make every effort to respond to your questions as soon as possible at the end of the work day...very busy electrical company - your patience is appreciated. Stop by and see us at: www.rkoelectric.com
Experience Licensed Master Electrician with over 32 years licensed experience - updated with the latest NEC Codes every 3 years. Over see the daily electrical operations of two electrical companies. Also serve as a judge (for Electrical Contracting Products Magazine) to help select which new products are fit and safe for electricians and the electrical market.
Question Hello Bob,
I am wiring in a 2nd breaker box on the other end of my home, 40 feet away, to run circuits for outside use from that end of the home. I am coming from my main breaker service box.
My 1st question: Can I use a 220 breaker in the main breaker box (100 amp), as a feed to my "New" breaker box so I will have 110 volts on each lead wire (Black & White) coming in the breaker box, giving me 110 volts on each new Circuit?
2nd Question: Can I use a 12-2 with ground as the feed wire to New breaker box 40 feet away?
3rd Question:Where is a good site to go to to get a good diagram of wiring in a breaker box? I want to do it right.
Thank You!
Paul
Answer Hi Paul,
Based on your description...you are wanting to install a secondary panel (typically referred to as a sub-panel) to supply additional circuits located ~ 40' from the main panel area. It's important to note that - In most States (if not all) ...this type of work requires an electrical permit....and a follow up inspection - by either the town/city inspector or a Master Electrician. Some States have a provision for the homeowner to do the work him/herself IF they own the home.....again - as long as all the work is inspected. All work must comply with the current NEC Codes adopted by the State (not all States have adopted the 2005 Code...some are still using the 1999 or 2002 Codes)
ANY sub-panel must have a minimum of a 4 wire feeder - regardless of the amperage size of the feeder...having 2 hots, 1 white neutral and a bare or green ground. (12/2 with ground will not suffice....12/3 with ground would be minimum) At the sub, the ground and neutral MUST be kept seperated (unlike back at the main panel where they both go to the same buss bar)...and this usually requires an optional equipment ground bar be purchased made for the sub panel. Do NOT use any bonding screw or strap that comes with the panel...there can be no bonding between the neutral and ground bar. You'll find most panels...even a small 10 circuit panel - to be rated at 100 amps (now code minimum) or higher. This does NOT mean you have to feed the sub with 100 amps...just that you can only go up to 100 amps..smaller but never larger. A main service panel has to be a minimum of 100 amps...but not a sub.
With that said....here are the answers in order:
1). Yes....a 240 volt double pole breaker will be required at the main panel to supply this sub panel. This will give you the two seperate 120 volt legs at the new sub....one black, one red.
2). NO....12/2 w/ground can not be used as the feeder...it must be at least 12/3 w/ground. Note - I suggest a larger size be used - the 12/3 will only be good for 20 amps on each leg....and you'd need to feed it with a 20 amp double pole breaker at the main panel....and have no spare amperage "headroom" if you want to add extra circuits later. (you may want to consider 10/3 w/ground on a 30 amp double pole or 8/3 with ground on a 40 amp)
3). I don't have any sites bookmarked for diagrams of breaker panel boxes...if I come accross one - I'll send it to you. I do however have a picture of one we wired (200 amp main panel...not a sub) whicb you may want to view for reference...it is under the link at my RKOELECTRIC.COM web page" some RKO at work pictures"...bottom of the 3 pictures. It is an old picture and kind of fuzzy....so you may want to save the image and zoom in on the panel.
I appreciated your desire to "do it right"...this kind of electrical work HAS to be done right....hence the permit and inspection requirements.
Hope this helps...if you run into problems or have new questions..please follow-up...I'll try to help out all I can.
About Electrical Wiring in the Home
This site answers questions related to home electrical wiring, home wiring, general electrical help,and other electrical questions related to aleternating current (AC). You can find help on the National Electical Code, home electrical issues, wiring electrical outlets, installing lighting, electrical grounding, and general electrical help for do-it-yourself projects not require an electrician. If you do not see your home electrical wiring question answered in this area then please ask your electrical wiring question here
