I am replacing a light switch and found three black wires going to it. Two go to the screw terminals and one goes to the push terminal: switch

I verified with a multimeter that the central and bottom terminals are always live, and the top terminal is live if the switch is in the up/on position. Is it safe to just pigtail the bottom two wires together when replacing the switch? The new one only has one hot wire.

  • 1
    I'd also replace that sketchy crimp on the grounds and put a proper wire nut on there. And run a pigtail from the ground bundle to the green terminal on the new switch - especially in a plastic box it's important to not skip that connection.
    – J...
    May 12, 2019 at 11:03

2 Answers 2


Yes, the correct way to deal with this is to wirenut (or otherwise join in a listed manner) those two wires and a short pigtail together, then connect the pigtail to the new switch.

  • Can you tell us why that old switch has three connectors? What's their function? May 12, 2019 at 12:24

What you have there a switch that is in line of a circuit. The power comes in and goes out to contiune the circuit. Only one of those black wires is actually live that is the feed coming off the circuit panel.
The third wire would be considered your switch leg which will power your device off the switch.
Normal procedure for cutting in that box would be to wire nut the feed with the other black wire continuing a circuit as well as a third black wire which is considered a pigtail to power your device ie: the switch the white wires which are the neutrals of course stay together to continue the current flowing through them. The crip on the grounds is a approved method of securing the grounds it is a crimp. there are some electricians who actually prefer that method then a wire nut because it is harder to remove. Also because the device is a switch by code and is not required to have a ground although it's always a good practice to put one on it. So if you like you can recompress the crip to remove it add a pig tail to the ground and either Re-Use the crimp after the ground wires have been twisted together or apply a wire nut.

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