I installed a new outlet and tied it in with the rest of the outlets in the room in a metal box up in the attic. The house is wired with 14-3 throughout, even on outlets and switches that only require 1 hot. I wired the new outlet with 12-2 before even checking to see what wire the other outlets were using. To make a short story long, two of the outlets are no longer working. I checked the wires in the attic and sure enough the 14-3 that feeds those two outlets is cooked.

My question is do I need to wire up the new outlet with 14 gauge, or did that have nothing to do with the other wire getting fried.

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    Can you post photos...? – ThreePhaseEel Oct 4 '17 at 22:22
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    Wire size was not the problem. You need to investigate the three-wire scenario to understand why it was done that way. – isherwood Oct 4 '17 at 23:29
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    What method did you use to splice the wires? Did you dismantle that method and what did the wires look like when you did? – Harper - Reinstate Monica Oct 4 '17 at 23:56

OK you don't really give us much information, but I thought I should address what we know. First I recommend to all DIYselfers to never make branch circuit changes like you did since you really do not have the experience level. If the original electrician install 14/3 you have to assume he had a reason, and we may never know why.

So I would advise you take out the 12/2 and reconnect your circuits back to 14/3 connecting color to color. If nothing else at you new receptacle addition you can wire nut it off and label it "unknown" and leave it as such in the back of the box where it can do no harm. Also I am bothered by your splice in the attic I am assuming you have installed that splice in a box and cover and not left it exposed in open air.

If this doesn't satisfy your question I suggest you take @isherwoods advice and maybe even bring in an electrician to help you trace out wires and explain what is happening in your system.


You said the red or possible second hot was not in use so if that is the case it is time to look for the root cause that fried the 14 gauge. I have rewired entire houses that were wired wrong from the start. 1 example was the white was hot, I had turned the power off and replaced an outlet in the middle of a dasiy chain when I turned the power back on it tripped immediately. I thought oops must be touching the metal box, but the reason was by placing the wires on the correct terminals created a short because the the bond in the main panel, I have also found DIY work where splices were made and the hot and neutral reversed. So this would be one thing to look for. Since you said the wiring was damaged I would be checking the breaker size with 14 gauge it should be a 15 amp breaker max , a 15 amp breaker will usually protect the wire from damage with a short but a 20 amp breaker can allow enough current to overheat the insulation on 14 gauge wire. Last you would have to had a short or miswire to cause the problem but some panels are notorious for not opening on a fault (FPE Stablock is 1 example) in any case make sure it is a 15 amp breaker. Verify that the polarity is correct black= hot , white neutral and they go to the correct places on the outlet. Black wire to black or brass colored screw, white wire to silver screw. If the box is metal at the outlet the bare copper needs to be connected to the box if plastic just to the green screw on the outlet.

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