Extending 12/2 Romex

[Alwayslearningelec]

Have 12/2 romex run to a particular location that was never used( microwave). Now the microwave is now in a new location so we have to extend the circuit. The microwave only requires 15A's. Can I splice 14/2 to 12/2? Thanks.

 

[Ravenvalor]

You have to stick with 12/2 or larger.

 

[infinity]

If you change the OCPD to 15 amps you can extend the 12-2 with a 14-2. Nothing else is required.

 

[tthh]

Seems like a bad idea to change out the breaker on #12 to 15A. Someone in the future might not know there is a wire gauge change and put it back to a 20A breaker. But, it can all be avoided by using #12 - if you can fish 14/2 to extend the circuit, you can fish 12/2 instead.

 

[Alwayslearningelec]

_Thanks

 

[infinity]

Seems like a bad idea to change out the breaker on #12 to 15A. Someone in the future might not know there is a wire gauge change and put it back to a 20A breaker. But, it can all be avoided by using #12 - if you can fish 14/2 to extend the circuit, you can fish 12/2 instead.

You could always put a note on the wire stating that part of the circuit is #14 AWG but that isn't required. Personally I wouldn't bother.

 

[LarryFine]

Seems like a bad idea to change out the breaker on #12 to 15A. Someone in the future might not know there is a wire gauge change and put it back to a 20A breaker. But, it can all be avoided by using #12 - if you can fish 14/2 to extend the circuit, you can fish 12/2 instead.

While the #14 would be compliant with a 15a breaker, I must agree with this post.

 

[infinity]

While the #14 would be compliant with a 15a breaker, I must agree with this post.

Have you ever run larger conductors for voltage drop compensation? We often run #10 branch circuit conductors for 20 amp circuits. No one should be changing the OCPD size without thoroughly investigating the entire circuit.

 

[suemarkp]

Where is this microwave? Most common locations have requirements for 20A circuits (e.g. kitchen counters, over the range hood) even though I've never seen a kitchen item with a 20A plug. If you are pulling new wire, I think it is short sighted to change to a smaller size as 12 should be just as easy as 14 to pull.

 

[LarryFine]

Have you ever run larger conductors for voltage drop compensation?

I have, but not residential. When I did, the upsized section did not start at the panel; it was between boxes.

 

[kwired]

You could always put a note on the wire stating that part of the circuit is #14 AWG but that isn't required. Personally I wouldn't bother.

agree. may be ok design decision but is not a requirement.

Any time I see "oversized" conductor on a particular OCPD, I kind of figure there is a good reason even if it isn't obvious.

 

[LarryFine]

Any time I see "oversized" conductor on a particular OCPD, I kind of figure there is a good reason even if it isn't obvious.

Do you presume the same if the wire is undersized?

 

[Another C10]

Now the microwave is now in a new location so we have to extend the circuit. The microwave only requires 15A's. Can I splice 14/2 to 12/2?

Many don't seem to agree with my input but here it goes, First of all stick with the same wire size because its fool proof and will keep you out of trouble.

technically the #14 rating is roughly 1850w, if never exceeded it would be safe, until someone decides to continue out of that box with additional loads which can happen, they'd now have a 2400w rated breaker allowing for an 1850w rated conductor to provide more service.

Not mentioned but as, if not more of a concern, the extended splice still needs to be accessible, don't be like the jack of all trade master of none handyman and bury the splice in the wall or behind a new cabinet.

The wiring will only utilize what the load requires.

 

[infinity]

To each his own. I would put #12 on a 15 amp OCPD everyday without a second thought. To me this is no different than converting a 240 volt, 30 amp electric dryer circuit to a 120 volt, 20 amp for a gas dryer and putting the #10's on a 20 amp OCPD.

 

[Fred B]

Whether code compliant or not, I'm going to say I've seen way to many instances on either repair or remodel and find 20A breaker starting off with 12awg and someone transitioned to 14awg that was hidden out of view that was definitely older than the 20A breaker installation. So someone saw the 12awg and decided they could put a 20A breaker in when the panel change was done not knowing of the changed wire site somewhere in the middle between receptacle outlets.

 

[roger]

To each his own. I would put #12 on a 15 amp OCPD everyday without a second thought. To me this is no different than converting a 240 volt, 30 amp electric dryer circuit to a 120 volt, 20 amp for a gas dryer and putting the #10's on a 20 amp OCPD.

Funny, I just did the same thing three days ago putting a #6 on a 20 amp breaker for someone changing an electric range to gas.

Roger

 

[roger]

Whether code compliant or not, I'm going to say I've seen way to many instances on either repair or remodel and find 20A breaker starting off with 12awg and someone transitioned to 14awg that was hidden out of view that was definitely older than the 20A breaker installation. So someone saw the 12awg and decided they could put a 20A breaker in when the panel change was done not knowing of the changed wire site somewhere in the middle between receptacle outlets.

This is where the electrician should earn his pay and verify what's on the circuit. If it's a DIYer, we can't stop it from happening and shouldn't loose sleep over it. The fact of the matter is a #14 conductor can handle well over 20 amps and wouldn't be a real problem anyways.

Roger

 

[Dennis Alwon]

Funny, I just did the same thing three days ago putting a #6 on a 20 amp breaker for someone changing an electric range to gas.

Roger

You are probably going to hell especially since the equipment grounding conductor has not been upsized proportionally with the other conductors. Shame on you....hahaha

 

[roger]

You are probably going to hell especially since the equipment grounding conductor has not been upsized proportionally with the other conductors. Shame on you....hahaha

Ooooops.

Roger

 

[winnie]

Funny, I just did the same thing three days ago putting a #6 on a 20 amp breaker for someone changing an electric range to gas.

Roger

This is one of the few situations where I think an adapter makes more sense than changing the circuit. By using the adapter the high amperage circuit remains available for a future dual electric/gas appliance.

Regarding the original post, I agree the if a 15A circuit is kosher, then it is ok to extend a 12ga circuit with 14ga and then use a 15A breaker. I wonder, however, if there is a chance that this might be considered a small appliance branch circuit even though it is intended to be dedicated to the microwave.

Jon