Hello I have a regular 3 wire 120/240 system.

Whilst looking at the service drop and breaker box I noticed the neutral wire seems very small. It is definitely smaller than the two main conductors..

I know the neutral is allowed to be smaller or at least was when the service was installed but it seems too small. Especially considering there is a 30amp outlet for an RV connected the box.

My question is can the neutral be LARGER than the conductors.. for example 1/0 if they are 2/0.

I don't know their sizes but I have some THHN wire that is 1/0

Would make quick work to have an electrician come hook it up and hard to overcharge me for 30 mins of work with me supplying the materials

  • 1
    Can you read the labeling on the wires in your service drop? Commented Jul 25, 2020 at 2:09
  • 2
    From what era? 50 years ago those neutrals were often way smaller than the hots. Recently they tend to be two under. We do need to know size to answer properly, though. It's probably stamped rather than printed if the wire is fairly old.
    – isherwood
    Commented Jul 25, 2020 at 2:32
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    When you say service that usually encompasses wire feeding meter and wire between meter and service panel. Replacing one piece without the other would be mostly pointless, and working in live in a meter base is hazardous (particularly an old one). Contemplating risks, mitigation, unanticipated conditions, permits/fines, really this isn't a "quick work" job. Commented Jul 25, 2020 at 15:10

1 Answer 1


You can always make wires larger than are strictly required.

So if your hots and neutral all must be #6, you are welcome to make the neutral #4.

In fact, one sneaky reason to do this is that a #6 neutral MUST be white or gray. Whereas a #4 can be generic black, and marked with white or gray tape to designate it as neutral. So if you wanted to avoid a run to the store, it might be a good play.

The Code requirement there is that #6 or smaller wires must be white or gray for neutral, green, yellow-green or bare for ground, and hot can be any other color. With #4 or larger, the electrical supply houses don't want to stock 3 colors of the big stuff, so Code allows you to re-mark with tape or paint to any base color, to indicate the function.

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