During building of addition I had to make some changes to existing house wiring in places. Today I ran across a duplex receptacle that has one 14/2 romex and also one 12/2 romex. I'm not sure without testing which one is the incoming power but I'd guess its the 12/2 without looking. The breaker is a 20A which should have all 12/2 wiring. This wiring was done back when the house was built in the 50's. It appears the 14/2 is the outgoing wire that feeds power to a switch nearby for the bedroom light. Should this 14/2 wire be removed or safe to leave to the switch? I'm installing a new fan and light combo unit where the existing bedroom light is due to changes made at egress to addition.

Thanks for your insight.

 

That 14-2 addition should be removed.
Since the circuit is protected at 20A.... that calls for all #12 wiring.

 

That's what I thought but wanted to check as it will take some more lath and plaster removal. I have a feeling there is a lot of 12ga and 14ga mixed within same circuit in a lot of places in this old house. Must have been common back in the 50's?



Another option would be to replace the 20A breaker with a 15A breaker? This would be safe practice also, correct?

 

Replacing the breaker would ensure the smaller wiring is protected until you could change out the #14.

 

I was hoping to use this JB in my basement that used to supply power to old electric baseboard heaters that are long gone. There is no longer any heaters and nothing on the circuit as breaker was removed. I wanted to hook the wire up to a 20A breaker and wore all lights for my addition to it as the JB is directly under where my first light fixture will be. The issue I see is that the old 12/2 wore has a small ground wire (maybe 16 guage). Is it still safe to run everything out of this box to all lights as 12/2 with 12 guage ground? Or does this homerun need removed from JB back to panel box and ran with new wire with 12 ground?

 

Guessing the 16 guage ground isn't ideal but would be ok for a ground?

 

Reduced ground cables can continue to be used if they are left as-is (grandfathered), but the circuit cannot be extended as it would be non-compliant per modern code.

As a practical note, be careful with those old reduced grounds as they get pretty fragile, especially if there was any moisture or corrosion on the copper. They are quite easy to snap or twist off when you are reworking the box.

 

Thanks for the info. I'll remove the wiring back to panel box and run a new 12/2 romex to this JB then. Then my entire new circuit for addition lighting will be all new wire with proper sized ground per code.


As for the 14/16ga ground wires, I did find them to be more brittle and have had many ~ 1/2 inch pieces break off the end in a few different gang boxes.