Est. 1998 — 27 years of woodworking knowledge
Electrical Question
Steven Mellott
>I am planning to install a 100 amp subpanel in my basement which will be 55 feet from my main panel. I will be runnning a 4 conductor wire in a "romex type" sheath. What size do the 2 feeder conductors, the 1 neutral conductor and the 1 ground conductor have to be? I've read a number of articles and am getting mixed information. Thanks.
I can look it up for you next week...
John in New Mexico
>I'm in Tucson right now, and didn't bring the code book with me :).
Public libraries usually have the NEC book in their reference section, and the IRC book's electrical section uses the NEC as its basis and is MUCH easier to navigate.
It's probably around 4 awg, depending on the type of insulation.
John
You also need to look at local code
Forrest Addy
>You also need to look at your local electrical code. The NEC represents the minimum. Local electrical code can increase requirements makes exceptions etc to comply with existing conditions and grafting electrical contractors. Regardless they carry the force of law.
If you ever have a fire one thing the local fire mashall investigates is possible electrical causes and code violations. More than one insurance company has used minor code offenses to avoid paying compensation. Even if you bootleg the work make sure it's up to code.
Re: Electrical Question
Barry Irby
>I am not an expert on the NEC by any stretch, but I believe (from table 310.16 Allowable Ampacities of Insulated Conductors.....) you would need a 1/0 for aluminum and a No. 1 for copper. (Insulation type TW,UF)
I can fax you the table if you want, or if you tell me the insulation type, I can tell you if a smaller cable would work.
Re: Electrical Question
Steven Mellott
>Thanks. I checked at the local Home Depot this morning and they told me that 2-2-2-4 aluminum is what I need.
Re: Electrical Question
Charles Williams
>If you are using a 100 amp breaker to feed the sub panel, 2-2-2-4 alum. would be o.k. Otherwise size the wire according to the feeder breaker, not the amp rating of the sub panel. And as Forrest Addy has stated, always check local codes.
If the budget can stand it, and it is available, my personal preference is to use copper wire.
Re: Electrical Question
Jim Swank
>If you do use aluminum - and most contractors would - make certain the lugs on the 100 amp breajer feeding the subpanel and on the main of the sub panel are all rated for aluminum as well as copper. I'd also use anti-oxidant compound on the aluminum conductor ends, although I'm not certain it is strictly required with the newer lugs. Oh, and since you're actually pulling a separate ground conductor as required by code, make sure that the neutral lugs are not bonded to the ground lugs in the sub panel.
Re: Electrical Question
Steve Schoene
>But, before the guy came to work at Home Depot he could about as easily have been bagging groceries as working in the electrical trades. I'm pretty leary about trusting advise from store personnel, let alone those who work at the big boxes.