Help with breaker.

First off I want to tell you guys that I have passed the NACHI test, the SOP quiz, and completed the ethics obstacle course. I am on my way to becoming a member.

Now, I am doing a mock inspection for homework and I came across this and am a little lost. It is a 2 pole 20 amp breaker. I know it goes to a 240 volt receptacle. I am not able to see the the labeling on the insulation, but it appears to me to have an 8 AWG copper conductor. My question is; why an 8 AWG, shouldn’t it be 12 AWG?

This is how I was going to report this on my mock report: “There is a 2 pole (240 volt circuit) 20 amp breaker that appears to have an 8 AWG conductor connected. I do not know the application of this circuit and am unable to determine if this is the proper size conductor gauge. I recommend it be checked by a qualified electrician.”

What causes you to believe that this is 8 gauge, and why would that concern you? There can be reasons to be concernd, if this is in fact 8 gauge, but that doesn’t seem clear at this point. Looks like #10 solid with type TW insulation, to me.

I believe it is 8 gauge because it appears to be the same size as the wire above it that runs to the 2 pole 50 amp breaker. Although not visible on the pictures, I can just make out strands if I look at the right angle and shine a light where the wire enters the breaker. I have posted an uncropped pic below. Sorry, I should have provided this pic before. The only concern I can think of is that it may cause nusance trips of the breaker. And yes, I did report the presence of rust on the lugs.

Although the wire is over sized for the breaker the breaker will still trip the main thing to look for is wire undersized for the breaker as this will cause a fire hazard. Hope this helps. J. Marcus…

Well, that breaker’s terminal is only rated for up to a #10, and it also appears that they may have cut strands to get it to fit. With the added perspective from the new picture, it does appear to be #8 and calling it out was righteous. The “fix” for any that are interested would be to pigtail on a short piece of #10 or #12 onto that existing #8, and terminate the smaller gauge pigtail on the breaker.

Good for you at least you ask the questions .
Many great people here to try and help .
Do not be shy and give as much information as you can.
Read, there are many many great posts with a lot of Info on this site.
Call if you need more help many do.

Does the 240 volt circuit have anything to do with the larger gauge? Does the application of the cicuit mean anything? I think I read somewhere that if it was for some sort of a heating appliance the gauge would need to be twice as thick as a normal wire.


When examining circuits with wire that appears to be larger than the ampacity of the breaker would really need, the only thing you need concern yourself with is whether the breaker’s terminal is rated for a wire of that gauge. There is a variety of reasons why a seemingly “too big” conductor may be terminated, and none of them are troublesome as long as the terminal can take a conductor that gauge.

So I guess the only issue is nusance trips. I guess I reported it properly.

No, not at all. Especially since you have no idea what’s connected at the other end. What was the rating of the receptacle to which it was terminated?

It is a 240 volt 30 amp. On that note. HI’s are not required to check every receptacle for the proper amp as compared to what is in the sevice panel, are they? I only know this one because it is only 1 foot away from the panel.

Beats me.

Anyone else have any thoughts?

Marc , you said you think they stripped some of the strands.
Are you guessing based on the electrical tape?

Also I ounce heard stranded is better .Any thoughts.
Mike that is a small amp circuit for a double.

Stranded is a better conductor, because it offers more surface area for the electrons to travel. And it is a double because it is a 240 v circuit.

Michael, When you get you membership, come and visit a NACHI CHicagoland chapter meeting.

  1. The larger wire will not cause nuisance trips. The item connected to the other end may require more amperage that the breaker will allow but that is due to an undersized breaker, not an oversized conductor. Replacing the breaker with a larger breaker will take care of this, as long as it does not exceed the ampacity of the conductor. On that note, as was stated earlier, the terminal should be rated for the conductor size. If there were strands cut off of that conductor, it will no longer be able to conduct it’s original intended amperage unless the end is cut off and the original size returned.

  2. 120 or 240 has noting to do with wire size. Wires are sized for varying capabilities to conduct electricity. Larger wires will allow more amperage. Think of a conductor as a garden hose vs. ice maker tubing. You can not flow as much water (electrical amperage) through the tubing as you can through the hose. They both have the same pressure, but one can carry much more at one time than the other. Try to force too much water through the tubing and it will burst. Try to force too much electricity through a wire and it overheats, melts and catches the home on fire.

  3. Electric heating units will require a larger conductor than a general use circuit, not because it is a heating unit, but because it requires more amperage. There should be a rating for the maximum size disconnect and/or amperage on the data plate. This is for sizing the disconnect, not the wire. The conductor can be larger than needed, but needs to be sized appropriately to carry the current rated.

  4. The only way to check outlets for amperage is to perform load testing. This is way out of our scope. There are some inspectors who check the outlets for exact voltage/outlet, but not amperage.

I highly recommend that you get additional education on electrical prior to performing real inspections. This is the weakest area for most inspectors and I hope that you don’t take offense, but it doesn’t sound like you even know the basics. Lack of knowledge in this area and making improper recommendations will come back to haunt you. Remember that you will have electricians call on you to inspect their homes too. You should be able to at least understand the difference between voltage and amperage as well as conductor ampacity.

Thanks for the information. As far as education, I am currently taking classes and we just started electrical. I do know the basics, but, as with everything else there are exceptions to the rules. And I do not believe that every exception can be taught or covered in a classroom setting. I posted this so that I could get additional education and take advantage of the years of experience on this site.

Thank you very much for the input and I will heed your suggestions.

It was more of an educated guess based on the presence of the tape to “disguise” what they had done, and based on what I think it would take to get a #8 under a captured square washer. The general rule is that any time you see tape on wires, be suspicious. There are very darned few reasons to use tape on a residential wiring installation.

Good deduction.
Always love the detective part of this job.