Stranded copper in breaker box.

Is stranded (not solid) copper wire allowed when making connections in the breaker box? Hopefully the picture will load and you can see the wires.
Thank you in advance,



I don’t see a problem, but I am Canadian. :wink: The only thing I would have done is twisted the ends of the strands to keep them together and clean so they don’t fray under the screw as shown in your photo. Raymond Wand Alton, ON

Stranded is okey dokey.

One caveat to be aware of concerning stranded wires in a breaker panel is to be on the look out for those times when the diameter of the wire is too large to fit into the lug and some clever little spud decides to “trim” some of the strands off to make it fit.

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:slight_smile: :cool:

As long as the stranded wire is not from an extension chord.

Homemade Extension cords in the attic%between%

Thank you everyone for your answers.

The NACHI message board ROCKS!!


Treesh Home Inspections

isn’t there different lugs for stranded wire??

There are different lugs for “fine stranded wire” but this refers to the very fine wire you use for battery cables and such. It becomes a problem in photovoltaic arrays where this type of wire can be used.The regular THHN/THWN style wire can be used in normal lugs.

thanx Greg, for clearing that up. i knew i’d seen “strand wire lugs” in supply houses, but was unsure of there use.

Answered my question today…Search and you shall find.

Another inspector and electrician told me this was no issue today. Then a different electrician told me it was a safety hazard.

Did he / she elaborate on why it’s a safety hazard?

The electricity returning on the cut neutral wires has nowhere to go and can cause the panel to overheat. This can lead to a fire

What is the specific issue the use of stranded conductors or someone removing several strands?

There is nothing wrong with stranded conductors. To the contrary, multi-strand conductors are superior to single solid strand conductors in a variety of ways.

The ampacity of a standard stranded conductor is reduced by 5.26% for each strand that is cut. American wire gauges are conservatively rated, so a single cut strand would not represent much of a hazard as a practical matter, but it would no longer conform to its UL listing and it would not comply with NEMA standards.

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If the neutral is cut and there is no return path, there would be no current flow, so how would that cause the panel to overheat or lead to fire?

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He said the previous electrician created a dangerous condition in my main panel by grouping a bunch of neutral conductors together in a lug too small for it. Because the lug couldn’t fit all the grouped conductors, some of the conductors (the ones that don’t fit in the lug) were cut short.

The “dangerous condition” was a concern about overheating and overloading. He said multiple conductors forced into a space too small can lead to overloading, which can lead to overheating and is a fire hazard.

He also said cutting strands compromises the integrity of the connection because the remaining strands have to carry more load than they’re rated for. It’s also a code violation.

I’m not an electrician so I’m not sure. But makes sense to me. What do you think?

Ashlee, most lugs are only listed for use with one conductor. Neutral bars typically allow 2 groundING conductors. Multiple conductors in a lug may not have the proper torque or contact area to make an effective connection.

Removal of strands reduces the ampacity of the conductors.