How to determine what size romex wire you need: for your electrical project

How to determine what size romex wire you need is easy. You've got a small electrical project to tackle but you're not sure how to go about determining what size romex cabling you need. Do you get the 14 gauge romex wire/cable or do you get the 12 gauge wire/cable? How do I know which one to get?....and....does it really matter? Of course it matters!! It may help to know what size breaker you're going to use & maybe you're connecting up to an existing breaker?....or maybe all of your breakers are 20 amp? How does this help in determining what size romex cabling to get at the store? You know you need to figure this out. I guess you need "joe" after all!!....lol.

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[strumpeteer]

First of all, thank you taking the time to share your knowledge to help others. IMO, if you are certainly sure that the wire you found was a 14AWG on a 20 amp breaker, I really hope you changed it to a 15 amp breaker for the safety of you and your family. :)

[VideoJoeKnows]

@strumpeteer I probably should've changed it but I felt there was no harm to do it this time, as you would not be able to add to this circuit, given the location used was under the AC unit & would be very difficult, if not impossible, to add anything else on this particular circuit, given the location. Thanks for your comments.  Joe :0

[cardoworld22]

Great post!!!!!!

[VideoJoeKnows]

@cardoworld22 Thanks for taking time out to send me your comment. Keep watching....as the more you watch, the more you'll learn!!....lol. Joe :0

[VideoJoeKnows]

@Chewylu103 The electrician probably checked the load on the AC unit, when intstalled, & determined that a 14 gauge wire was ok?... as the AC unit has been here for around 6 years & nothing has happened to it.....yet! The AC was not upgraded but if it ever was, should not be any larger than what's there now. The breakers were in a condo & maybe the requirement was that this condo was not to have any 15 amp breakers in the sub-panel?....not sure. Thanks for your comments. Joe :0

[Chewylu103]

@strumpeteer yes i agree using a number 12 on a 15amp breaker is fine, because the wire is oversized for that breaker and the breaker will trip before current reaches the wires ampacity. My concern was that he was giving out false information, he said that the 14 was on a 20 amp breaker if i remember correctly, its wrong to just add a 12awg potentially masking a problem. because you see the breaker at 20 amps, the wire at 12 and run 20amp equipment. boom, 14awg melts, possible fire.

[strumpeteer]

@Chewylu103 ....and even if the careless electrician

doesn't check which breaker goes to what circuit, a 15A breaker will

obviously trip before overloading the 14AWG with 20amp rated

stuff.:)

[strumpeteer]

@Chewylu103 IMO, using a 12G wire on a 15amp breaker is fine.

In the future, even if the idiot electrician, who assumes that a circuit is

automatically on a 20A breaker just because he sees a 12G wire,

will eventually learn that it's actually on a 15A breaker when he goes

to the panel to turn off the power to that circuit (assuming that he

doesn't work on live circuits. )

[DAZUPYOU]

Now that is a very nice tip thank you:):)

[VideoJoeKnows]

@Chewylu103 Thanks for your attention to details.  Joe :0