Thread: Breaker Oversize ?

Its a 30 amp breaker but the wire seems a little small for the breaker? Sorry I know the picture is not clear but the wire is about the same sizes as a 15 amp breaker. Any comments on this?

Thanks

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I can't really tell from the picture but, in comparison to the one above, it does look small.

Is it by chance for an A/C unit? This is one common (and allowed) instance for wire to be undersized. Basically, the only time the full power draw is in effect is for a short time during start up. Otherwise, it's running much lower so the wire doesn't overheat.

If it's not an A/C unit and it is smaller than 10 gauge - it's incorrect.

Originally Posted by Mark Tran

Its a 30 amp breaker but the wire seems a little small for the breaker? Sorry I know the picture is not clear but the wire is about the same sizes as a 15 amp breaker. Any comments on this?

Thanks

Can be difficult to tell from a photo, but I'd say those look like #10 conductors on the 30 amp breaker.

If those are #8s on the 40 amp breaker above, it looks like #10s, definitely not #14s.

As MF said there are cases where the breaker will appear oversized compared to the conductors. You need to determine the load served.

Originally Posted by Mark Tran

Its a 30 amp breaker but the wire seems a little small for the breaker? Sorry I know the picture is not clear but the wire is about the same sizes as a 15 amp breaker. Any comments on this?

At the very top of the photo is what looks to be #14 to what I presume is a 15A breaker. The wire in question is larger than that and relative to the size of the breaker and aforementioned wire looks to be #10.

At the top I think its a #10 gauge for 40 amp breaker which is fine the bottom is my concern it looks like a #14 gauge for a 30 amp breaker.

Originally Posted by Mark Tran

At the top I think its a #10 gauge for 40 amp breaker which is fine the bottom is my concern it looks like a #14 gauge for a 30 amp breaker.

Mark - There is no way the conductors for the 40 amp breaker shown in the photo are #10.
The very top conductor, that little black one all the way at the top, looks like it might be #14.
The ones on the 30 amp breaker look like #10 to me. They really don't look like #14.

Originally Posted by John Arnold

Mark - There is no way the conductors for the 40 amp breaker shown in the photo are #10.
The very top conductor, that little black one all the way at the top, looks like it might be #14.
The ones on the 30 amp breaker look like #10 to me. They really don't look like #14.

I agree with John. There is no way the wires on the 30 look the same as the top black conductor in the photo.

Okay sorry but I'm a little confused? I update the picture, looking at the picture you guys think that's the wire size? I thought the bigger wire with the 40 amp looks more like a #10 gauge? and the smaller wire at the bottom connecting to the 30 amp breaker looks more like a #12 or #14 gauge ? Please explain

Originally Posted by Mark Tran

Okay sorry but I'm a little confused? I update the picture, looking at the picture you guys think that's the wire size? I thought the bigger wire with the 40 amp looks more like a #10 gauge? and the smaller wire at the bottom connecting to the 30 amp breaker looks more like a #12 or #14 gauge ? Please explain

There are 3 black-insulated conductors and 2 red-insulated conductors in your picture Above the two you labeled "#14?" is an unlabeled black-insulated conductor that looks to be #14. The breaker for that conductor is just out of the picture.

Below that is a double-pole 40A breaker with what looks to be #8 stranded. Below that is the double-pole 30A breaker with the conductors in question. Those conductors, based on their size relative to the top-most black conductor as well as the conductors on the 40A breaker, would appear to be #10.

All the same, the title of this post is potentially misleading. The question we need to answer is whether or not the wire is of sufficient size for the load in question. If the over-current protection device is for a fixed in place appliance (e.g. A/C unit) then often the nameplate on the appliance will specify what size over-current device is appropriate and the device load (along with any derating if necessary) will determine what size wire is required.

Well said Corn.

Mark, why do you think the wires labeled #14 in your updated photo would be larger than the ones you labeled #10? American wire gauge runs opposite from a numerical increase, ie larger number = smaller wire. I certainly hoped this would be covered in a basic training course.

Originally Posted by Jim Port

Well said Corn.

Mark, why do you think the wires labeled #14 in your updated photo would be larger than the ones you labeled #10? American wire gauge runs opposite from a numerical increase, ie larger number = smaller wire. I certainly hoped this would be covered in a basic training course.

Not bust anyone's chops here - But I would have thought wire size ( at this small of a size) would be basic knowledge for an inspector. It's not rocket science to determine the size of a conductor in the #14 to # 6 size range.

Was that conductor in a cable assembly ( NM Cable )? Why not follow it to see what cable it is in and read the writing on the cable ?
A picture of conductors on a circuit breaker leaves too much room for guessing

Originally Posted by Jim Port

Well said Corn.

Mark, why do you think the wires labeled #14 in your updated photo would be larger than the ones you labeled #10 ? American wire gauge runs opposite from a numerical increase, ie larger number = smaller wire. I certainly hoped this would be covered in a basic training course.

well that's what I mean I was confused about the replies, people are telling me that the larger size wire looks like a #14 gauge which makes no sense to me when it looks a #10 or #8 gauge. That's why I added the question mark because I didn't get what people were saying.

mark
suggest you go to an electrical shop and get a sample of gauged wires to carry with you. this is something all new inspectors should do.or carry a code check book with you
charlie

Originally Posted by Mark Tran

well that's what I mean I was confused about the replies, people are telling me that the larger size wire looks like a #14 gauge which makes no sense to me when it looks a #10 or #8 gauge. That's why I added the question mark because I didn't get what people were saying.

I think there is a misunderstanding here. Posters are talking about the top most wire in your photos being a #14, not any of the conductors connected to the 2 pole breakers.

One of these should run about $28.00 or so. Keep in mind that stranded wire measures about one size larger than solid.

Obviously for use with power off.

It is NOT a good idea to try to train yourself to recognize wire sizes by the outside size of the insulation because the types of insulation over the years, and several currently used types, vary greatly in thickness. Old rubber and fabric #10 stranded wire looks much bigger than modern solid #10 does - the old cable looks twice as big.

Which brings up the point that you're way too far into a panel for your own safety to be checking wire sizes unless you are trained or the power is off - preferably both.

Originally Posted by Bill Kriegh

One of these should run about $28.00 or so. Keep in mind that stranded wire measures about one size larger than solid.

Obviously for use with power off.

"Obviously for use with power off."

Well worth repeating when using one of those.

And make sure you get the right one too ... there are two types of those: a) for ferrous metal (steel, etc.); b) for non-ferrous metals (copper, aluminum, etc.) Using the wrong one will lead you astray.

Actually, this guage is for any wire that has an AWG size from #30 to #0 and it doesn't matter what the material is. It's not a sheet metal guage.

Originally Posted by Bill Kriegh

Actually, this guage is for any wire that has an AWG size from #30 to #0 and it doesn't matter what the material is. It's not a sheet metal guage.

Bill,

So it is: Wire Gage - General Tools & Instruments

It looks just like my two gages, one for ferrous metals and one for non-ferrous metals, the non-ferrous metal gage is the same as mine ... which also says American Standard Wire Gage, but also says Non-Ferrous Metals too. That not only works for wires, but for "all non-ferrous wires, metals and rods such as copper, brass and aluminum".

The other one ( Sheet Metal Gage - General Tools & Instruments ), which I also have, is for ferrous metals such as sheet metal and plate iron and steel.

Not sure which, if either, is the right one to use for drawn steel wire? I would think the ferrous metal gage, even though it is for sheet and plate metal, but, then again, it is not a "wire" gage.