Copper Wire Gauge

I know this type of question has been asked a million times before but I thought the gauge looked a little small on the white insulation wire going into the breaker at the top left of this GE panel. 40 amp breaker. There was no writing on the outer white sleeve to confirm but it looked to be the slightly smaller than the black wire on the opposite side panel whose wire appeared to be a 10 gauge on a 40 AMP. The AC data plate allowed a MCA of 30 AMP so I believe it is allowed. Home built 1947 NM but didn’t look super modern NM. Thoughts?

Yes, it sounds like, from what you say, it is allowed.


Any idea about the white wire gauge Larry?

Not a problem… If you are asking about the black sheathing at the right, it says 10/3. The label says you can have up to a 50 amp breaker, and 29.5 minimum ampacity. However, this is odd, from what I usually see… Normally the breaker and the gauge are only one size off from each other, not two.

The white ones on the left look like 10, but it is too hard to tell from a photo. Is that breaker also for hvac? Otherwise it would be an oversized breaker

There are plenty of other issues wrong with that panel though.

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No legend. Only the AC and a few others were marked. I know the bonding jumper was dangling in mid air below the neutral bar. One neutral was doubled with a ground and some bushings were missing. What else you got?

Other than your wiring concerns, a licensed and qualified Sparky needs to make repairs (possibly significant repairs/replacement) to that homeowner/handyman installed panel anyway!!




One or all, still needs corrected.

Jeffrey got the bushings. That SQ D breaker isnt allowed, it looks like a GE or Siemens panel.
And the feeders appear to be missing a neutral conductor, I assume the bare conductor is being used for grounding and neutral?
This looks to be a subpanel, correct?

Main Panel. Only one in the home. The meter is directly to the right. There was a 60 amp fuse box in the garage.
GE panel is correct.
The bare wire is the service neutral. The home only had 1 grounded receptacle. The ground wire is the armored wire at the bottom. Not that it much matters with just one item grounded.

I missed the square D breaker as I was so focused on that wire. Thanks. Good thing still working on report.

Interesting. So how is the 60 amp panel fed? Does that panel have more branch circuits? Because I only see two 20 amp breakers, (assuming one for bath, one for kitchen?) And no breakers for the stove, dryer, or water heater?
Sorry, just trying to help.

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You’re good. I’m not entirely sure as the legend is not complete but it may be that 40 amp breaker. The wires coming into the fuse are small. The biggest fuses in use there are 30 AMPS. Only 2 of them were in use if I remember. Everything in the home was gas. It was a 60 AMP panel but didn’t look like 60 amp wire sizes. Lots of issues. Also a gas odor at multiple areas of the home. Lots of issues…

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Yep, all in all, its probably best not to try and list every single defect anyways, but it appears both panels probably need to be completely re-done!

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The white cable on the left looks like UF cable or someother type of cable, just not NM cable. You can see that the conductors are actually black and red.


That would be best. This home had clogged toilet supply, sulfur in well water, discoloration, visible sediment, galvanized pipes, terrible hot water pressure, a “moat” around the back of the home where the hill just comes down to the home. Retaining wall major leaning and clogged drains. Every single concrete slab had major settlement and movement, likely due to poor soil or installation. Just a low income rural area unfortunately.

The conductors in the 10-3 NM should all be the same gauge.