6 gauge wire to a 30 amp breaker

**JIM MURPHY** · 10-26-2010, 12:13 PM

Can you have a 6 gauge wire go to a 30 amp double breaker? This was found in a panel today. There were three 60 amp breakers going to the Air handler, stove and electric on demand water heater. There was two 30s going to the compressor and washer/dryer combo. He had them all wired with six gauge wiring. Said he was told if the wire was larger for the 30 it would not matter.

Jim

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**Nick Ostrowski** · 10-26-2010, 12:42 PM

Oversized wire gauge size is not a problem, as long as it fits properly beneath the breaker lugs and does not need to be modified or altered to fit.

Oversized breaker size is a problem.

**JIM MURPHY** · 10-26-2010, 01:03 PM

Thanks a lot!

Jim

**Jerry Peck** · 10-26-2010, 05:40 PM

Originally Posted by Nick Ostrowski

Oversized wire gauge size is not a problem, as long as it fits properly beneath the breaker lugs and does not need to be modified or altered to fit.

And not just "as long as it fits properly" into the lug, read the label on the breaker and see if the lug is rated for that size conductors, it might not be ... even though the conductor may appear to "fit properly".

This comes down to something we have started saying more and more often - read the label to see if it is allowed. Those labels really are important.

**H.G. Watson, Sr.** · 10-26-2010, 06:07 PM

May be fine at the breaker, but is the wire oversized for the terminal block or receptacle, now that IS a question.

**Rollie Meyers** · 10-26-2010, 07:30 PM

250.122 (B) must be considered.

(B) Increased in Size. Where ungrounded conductors are
increased in size, equipment grounding conductors, where
installed, shall be increased in size proportionately according
to the circular mil area of the ungrounded conductors.

Copy & Paste from the 2008 NEC

If someone pulled 6 AWG conductors into EMT & used the conduit as a ECG, then no issue, but w/ NM or other wiring methods it does become a problem.