Main wire size

Correct size wire(s) for 200 amp breaker? Anyone have wire sizing chart? Thanks in advance.

3/0 in Canada

NEC, 200 amps=#2/0 Copper or #4/0 Aluminum, #2 cu=125 amps, all with some restrictions. Table 310.15(B)(6)-2008 NEC.

So to answer my first question?? Is this 2/0 in the picture(s)?

Looks like #2 Copper, from photo {2 AWG}.

Again I ask, Is this the correct wire size for 200 amp breaker and/or what is the difference between #2 and 2/0?? Thanks.

Did you read post #3? The answer is no for 200 amps.

2/0 (two naught) pronounced “two not” is a larger wire and will carry the 200 amps by your codes. #2 is good for up to 125 A depending its installation, configuration e.g. in open air, in a raceway, in a 3 wire cable, etc.

In the US wire sizes bigger than #1 go by zero’s or aught (pronounced ought) a derivative of naught.


After #4/0 the wire sizes start with their circular mil area in thousands.

I still say “naught” …we keep dropping letters/words. Pretty soon we’ll all be writing like our kids text language…R U OK w/ that?;-);-):shock:


/nɔt/ Show Spelled[nawt] Show IPA
***–noun ***1. nothing.

  1. a cipher (0); zero

:cool: It’s all good.

Go to the electrical supply house here and say "I need some three naught". First they look at you really funny then they say “you must be Canadian”.

Wow and the whole time I thought it was “Ought”.
**aught ***or ***ought ****2 ** (ɔːt)— ***n ***a less common word for nought

That would be like asking for “three goose egg” wire … :mrgreen: … but maybe they would look at us just as funny if we went into a canuck supply house and asked for “three ought” wire … they might say “dont ya mean ya want some three naught wire … ehhhh” … :p.

Get yourself a copy of Code Check, which has the attached table and a bunch of other usefull basic code info for HI’s. With that table keep in mind that you can get more out of wires in conduit, and it doesn’t necessarily apply to AC condenser circuits (check the nameplate for that).


It probably is but I used 3 naught!