What gauge should I use

ACHTUNG · 05-29-2011, 10:12 PM

I am a decent handyman, capable of wiring most any situation. My dad just build a home, i wired it, and we passed inspection on the second attempt (he made me fix a few things but said I did a good job).

HERE IS MY QUESTION: I am about to start my own home, and whereas my dad already had the main service meter to the home, i do not. The service box is some 60 feet away. I'll have an electrician do this part, but he told me to get the wire and talked in circles when I asked what to get.What guage aluminum wire do i need that will suffice for 220 amp service. Is it 4-4-2? (for some reason that sticks in my mind). or is it something else? i have all the conduit and everything I'll need - just need that wire guage!

THX! Jim

Jim Port · 05-29-2011, 11:09 PM

I think you might have misheard something. For one thing 220 amps is a strange service size. Normal service sizes are 100, 150, 200.

#4 is nowhere near large enough for anything close to 200 amps. 4/0 AL would be for a 200 amp residential service.

WillK · 05-30-2011, 12:50 AM

I think maybe I can help out on this as a lay person...

Sounds like you might have some confusion over wire gage lingo, I kinda went through this confusion myself.

Wire gages go down in size as the wires get larger. Most often DIY projects will deal with 15 amp and 20 amp circuits that typically use 14 gage and 12 gage copper wire respectively. You might get into 10's 8's and 6's for 240 volt appliances.

Those of us crazy enough to attempt panel feeder type work will be the ones that run into wire gages heavier than 2 gage.

So wire sizes logically go down to 0. When the wires get bigger, nomenclature used to be that you'd get more zeros. You'd go to #0 gage then #00 gage then #000 gage then #0000 gage. Now the lingo is to call a zero a "naught" and refer to the number of "naughts". #0 is called "one naught" and written as 1/0. #00 is called "two naught" and written as 2/0. And so on up to 4/0.

4/0 aluminum is the size needed for 200 amp service. Apparently larger sizes are referred to in mm diameter, but anyone not an electrician is unlikely to be daling with that. For my jurisdiction, I'm not allowed to do a service larger than 200 amps as a homeowner. And larger cable than 4/0 is not going to be found at a big box store.

Saturday Cowboy · 05-30-2011, 01:06 AM

thank you for that well written post, WILL

SD515 · 05-30-2011, 09:05 AM

Quote:

Originally Posted by WillK

Apparently larger sizes are referred to in mm diameter...

Clarification...
Expressed in circular mils not millimeters. KCM or MCM. ie. 250,000 cm=250 KCM

rjniles · 05-30-2011, 11:21 AM

When I first read WillK's post and the term "naught", I thought he had made an error. I had always heard and used the term "ought" as in 4/ 0 wire is 4 ought. Did a little research with Google and found that "naught" is also a legitimate term.

Sorry I doubted you WillK

WillK · 05-30-2011, 12:36 PM

I think I've heard it both ways, possibly because when I first heard it I didn't know what it was because I thought of it as "four slash zero". Technically naught is nothing while aught is anything, so naught is more correct in terms of English. But I think any electrician would tend to find you more credible if you said "four aught" than if you said "four zero"

I'm just curious if this is a fairly recent change? We bought a new house in Indianapolis in 2007 and at some point I wanted to add a 240 outlet in the garage for a compressor, so to pull homeowner electrical permits for Indianapolis I had to take a test - for which the inspector allowed me to borrow his code book. (The test was more about knowing how to find code than whether you know code) In the code book it still referred to #0000 instead of 4/0.

rjniles · 05-30-2011, 12:54 PM

Naught vs ought.

From what I have read they both mean zero or nothing. Naught is more favored by the British and Aussies. Ought is more prevalent in the US.