How to tell wire gauge of old cloth romex?

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Old 10-09-17, 09:30 AM
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How to tell wire gauge of old cloth romex?

So I have been trying to clean up some of the wiring in this 1955 house which contains some original old cloth romex.

I am trying to determine the wire gauges of these wires. The cloth is grayish white with no label. There are two insulated conductors inside, each individually wrapped in brown paper. There is no ground conductor.

Looking at the solid conductor side by side with modern day solid conductors of #12 and #14 gauges, the copper looks like #14. Using a wire stripper against it the #14 slot strips it easy and clean. So it seems to be #14.

Yet there are five circuits with this wire and all of them are on 20A breakers not 15A.

Is there any sure way to determine the old wire gauge before I changed out the breakers?
 
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Old 10-09-17, 02:06 PM
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The only way to confirm wiring size is by sight..... or strippers like you've tried.
I've found that the older wire to be slightly larger than today's current wire. That means if the wire fit the #14 jaw..... it's #14 and should be on a 15A breaker.

It's very common to find #14 on a 20A breaker. It's like a free extra 5A of power without needing to upgrade the wiring.

It's just the same as finding 30A fuses screwed into a fuse box for a #14 circuit. Those 30A fuses worked perfectly..... never blew at all.
 
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Old 10-09-17, 08:01 PM
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it's very common to find #14 on a 20a breaker. It's like a free extra 5a of power without needing to upgrade the wiring.

It's just the same as finding 30a fuses screwed into a fuse box for a #14 circuit. Those 30a fuses worked perfectly..... Never blew at all.
lolllllllllllllllllllllllllllllllllllllllllll
 
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