Thread: "trimmed" Entrance Cable

This main entrance cable at the service equipment has been trimmed a little to fit. It's a #2 conductor, attached to a 100Amp main switch in a panel rated for 125Amps. Seems like they should have just put in a 125Amp main switch, but trimmed the cable and put it in a 100Amp instead. Is there a code reference for this being wrong?

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I don't think you need a code reference or will even find one for something like this. Wrong is wrong.

From the 2006 IRC
"

E3306.9 Terminals.

Connection of conductors to terminal

parts shall be made without damaging the conductors..."

Originally Posted by Rick Cantrell

From the 2006 IRC
"

E3306.9 Terminals.

Connection of conductors to terminal
parts shall be made without damaging the conductors..."

RC: In the land of NEC that's 110.14(A):

(A) Terminals. Connection of conductors to terminal parts shall ensure a thoroughly good connection without damaging the conductors and shall be made by means of pressure connectors (including set-screw type), solder lugs, or splices to flexible leads. Connection by means of wire-binding screws or studs and nuts that have upturned lugs or the equivalent shall be permitted for 10 AWG or smaller conductors.
Terminals for more than one conductor and terminals used to connect aluminum shall be so identified.

Originally Posted by Jon Errickson

It's a #2 conductor, attached to a 100Amp main switch in a panel rated for 125Amps.

I would not word it that way as it *is not* a #2 conductor ... *it was* ... but *it is not now* ...

Now it is an "unknown" conductor which has no ampacity rating and needs to be replaced (or if there is enough the end could be cut off and done properly or if too short then properly extended by properly splicing on another piece of conductor).

Simply put ... "They ain't allowed to do that." and they should have known it ... whoever "they" were at the time.

Originally Posted by Jon Errickson

This main entrance cable at the service equipment has been trimmed a little to fit. It's a #2 conductor, attached to a 100Amp main switch in a panel rated for 125Amps. Seems like they should have just put in a 125Amp main switch, but trimmed the cable and put it in a 100Amp instead. Is there a code reference for this being wrong?

That looks like a QOM1 100 amp Square D main breaker. If it is it should take up to a 2/0 awg as a maximum wire size for the lugs. Not sure about the square d as the neutral bar configuration doesn't look correct.

Product Detail - Schneider Electric United States


The NEC code reference for the violation shown is 110.14 (A) there are a few others but you only need one....

Thanks everyone for the replies.

I'm not a home inspector, but I am an engineer. What has been done to this cable is quite alarming. The safe current carrying capacity of a wire is a function of its resistance, and the resistance of a material is proportional to its cross sectional area in the direction of the current flow. (In the case of braided wire, take the sum of the individual cross sectional areas for each wire.)

In other words, all things being equal, if wire A is twice the diameter of wire B, then wire A will have 4 times the current carrying capacity of wire B. This is because the cross sectional area increases as the square of the diameter. Likewise, a wire that is three times the diameter would have 9 times the current carrying capacity.

It is difficult to tell exactly, but I would estimate that the diameter of the wire in this picture has been reduced by about half along a short stretch. If this wire was rated at 100 amps for its intended voltage, then along the trimmed stretch, its safe current carrying capacity would only be a quarter, or 25 amps.

I agree with Roger. That conductor should have easily fit in there. Why some guys do this is beyond me.

Originally Posted by Speedy Petey

I agree with Roger. That conductor should have easily fit in there. Why some guys do this is beyond me.

Yeah everyone knows you should never trim off the outside strands!
Always trim off the inside strands so the outside strands cover it up

Originally Posted by Robert L. Ayers

I'm not a home inspector, but I am an engineer. What has been done to this cable is quite alarming. The safe current carrying capacity of a wire is a function of its resistance, and the resistance of a material is proportional to its cross sectional area in the direction of the current flow. (In the case of braided wire, take the sum of the individual cross sectional areas for each wire.)

In other words, all things being equal, if wire A is twice the diameter of wire B, then wire A will have 4 times the current carrying capacity of wire B. This is because the cross sectional area increases as the square of the diameter. Likewise, a wire that is three times the diameter would have 9 times the current carrying capacity.

It is difficult to tell exactly, but I would estimate that the diameter of the wire in this picture has been reduced by about half along a short stretch. If this wire was rated at 100 amps for its intended voltage, then along the trimmed stretch, its safe current carrying capacity would only be a quarter, or 25 amps.

Very informational. Thanks for your post.

If this is a dwelling service (3 wire, single phase) then the original maximum rating of the wire would be 125 A per table 310.15(B)(6). Otherwise it is 115, (assuming USE conductor) before adjusting for ambient temperature or other factors, per table 310.16. (Jerry did I do it right?) Cutting the wire is only allowed if you cover it with duct tape, unless nobody sees it in which case it is OK until the fire starts.