Can I mix wire gauges?

Old 09-25-05, 07:08 AM
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Can I mix wire gauges?

On a recent job, I wound up splicing a 2' section of normal gauge (#14?) electrical wire in the middle of a run of heavier (#10?) electrical wire. Everything is working fine, but I've never mixed wire gauges and I was wondering if it poses any fire danger. Any thoughts?
Old 09-25-05, 07:14 AM
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The biggest issue is the size breaker you have used. The breaker needs to be sized for the smallest gauge wire in the circuit, excluding fixture wires.

#10 is normally protected by a 30 amp breaker, #14 by a 15 amp breaker.

If you have a 30 amp breaker you have created a potential fire hazard that should be fixed ASAP.
Old 09-25-05, 07:18 AM
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No ... except the circuit must be rated for the smaller wire, 14ga wire is rated for 15 Amps. Your #10 30 amp circuit is now a 15 amp circuit and must be protected with a 15 amp fuse or breaker.
Old 09-25-05, 07:31 AM
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There is no such thing as "normal gauge electrical wire".

Certain wire sizes are used for a reason. Either the wire is properly sized for the breaker and the load, or it is intentionally up sized to handle voltage drop. Sometimes larger wire is also used for use in the future. Regardless, the wire is sized for a reason.

It is not a good idea to mix wire sizes, especially for a short spliced in section. In your case, even if the circuit is protected by a 15 amp breaker (which it needs to be with 14 gage wire installed), someone may not see the smaller wire or know about it and up size the breaker.

10 gage wire is typically used for dryer electric circuits. An electric dryer circuit needs the 10 gage wire and will overload smaller wire.

Do the right thing, go back and use the correct size wire, to match the rest of the wire.
Old 09-25-05, 08:11 AM
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IMO this is never a good idea, for the reasons Racraft said. And even to use up spare wire you may have on hand.

Why would you even think of splicing a short piece of #14 to a run of #10??? #14 is considerably smaller.
Doesn't common sense kick in at some time?

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