OT: drawing more electical lines in my house...

[Hal]

I'm looking to finish my basement, the pure DIY way, and was thinking about problems i might run into when doing the electrical work...well, when I went to check the main box, I have a main breaker rated at 150 amps.  However, I already have 20 lines, 10 rated at 20 amps and 10 at 15 amps, for a total of 350 amps.  that confused me a little...I mean, I'm thinking 2 more lines can't really make too much of a differance.  And I know that I won't have _everything_ running at once, but still...I would think that that would be kinda dangerous or something.

Is there any sort of law or equation you use for relating main draw to indevidual line draws, or do you just kinda estimate max usage...?

I live in New York if that makes any differance ;-D

thanks guys!

[ErikMiller]

I have a main breaker rated at 150 amps.  However, I already have 20 lines, 10 rated at 20 amps and 10 at 15 amps, for a total of 350 amps.  that confused me a little...I mean, I'm thinking 2 more lines can't really make too much of a differance.  And I know that I won't have _everything_ running at once, but still...I would think that that would be kinda dangerous or something.

Is there any sort of law or equation you use for relating main draw to indevidual line draws, or do you just kinda estimate max usage...?

I did the wiring for my basement shop, and my suggestion is that you get the Black and Decker home wiring books. Old Electrical Wiring by David Shapiro is my bible, but it may be out of print. Also, if you post this question on the appropriate usenet group (alt.home.repair, I believe), you'll probably get many good suggestions.

It doesn't have to be set up so that there's enough capacity to run every circuit full draw simultaneously.

[Peter Snowberg]

This is why you have main breakers (or fuses) as well as breakers on individual circuits. You just want to make sure that every carrier (wire) is running within it's limits. There is no direct relation to the number of sub-circuits, just make sure you don't tax the main breakers and everything will be cool.

I would try picking up the book that Erik mentioned first, but there are a lot of good DIY home electrical books out there. I peeked at a Time-Life home electrical book at it looked really good. Try Home Depot, or the book rack of your local hardware store.

Suggestion: If you don't have one already, pick up one of those beeping inductive voltage tester pens and one "screwdriver" style with the neon light in the handle. You can't be too careful here and each tester excels at a little  different testing method (field vs. direct contact).

Best of luck on your wiring!

Take care,
-Peter

[biddingestimate]

It's great you're thinking ahead about electrical work! In your case, the total amperage of your circuits doesn't directly relate to the main breaker's rating since not everything runs at full capacity simultaneously. Electrical estimating services can help you properly size your panel and ensure safety with the right load calculations. In New York, local codes also have specific requirements, so it's always wise to double-check.

[bluebunny]

AI still too daft to spot twenty year-old thread... 

[mozz]

Not now. Just saw a picture or advertisement and the girl had 6 fingers, they still have problems with that.