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Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 7095
Experience:  Proven Professional 46 years Experience
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I am trying to replace a double switch. I have 2 black wires

Customer Question

Hi! I am trying to replace a double switch . I have 2 black wires and 2 green wires
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: Weeks!
JA: Do you plan on doing the work yourself?
Customer: Yes
JA: Anything else we should know to help you best?
Customer: The switches control 2 separate light fixtures - one in kitchen and one in dining room
Submitted: 23 days ago.
Category: Electrical
Expert:  Mike G. replied 23 days ago.

Hi, I'm Mike and I'll be assisting you. Please stand by while I review your question.

Customer: replied 23 days ago.
Do I break off the Terminal fin or leave it intact?
Customer: replied 23 days ago.
Does it matter which green wire and which black wire goes on the top or bottom? And can you confirm that black wires should be hooked to black screws, and green wires to brass screws?
Expert:  Mike G. replied 23 days ago.

A double switch needs a minimum of 3 black wires to control 2 lights. The tab is removed if you have 4 wires and they are 2 separate circuits.

Expert:  Mike G. replied 23 days ago.

Unless it was incorrectly wired, green wires are grounds and should not be part of the switching. Do you have a 2 wire voltage tester? Can you check the wire colors at the fixtures?

Customer: replied 23 days ago.
since I only have the 2 black wires and 2 green wires, I cannot have a double switch. Is that correct? If so, what type of switch do I need to buy?
Expert:  Mike G. replied 23 days ago.

Without testing, my guess would be a single pole switch.

Customer: replied 23 days ago.
I think the green wires (the green is electrical tape) is probably just what the super of my building had on hand. Our building was built in 1950 and we do not have any ground wires. I think think the green is actually supposed to be white tape
Expert:  Mike G. replied 23 days ago.

Do you have a tester? You need test not guess.

Customer: replied 23 days ago.
I just added a picture of the switch I bought. It actually doesn't even have space for 3 black wires, so that doesnt make sense
Customer: replied 23 days ago.
The switch instruction show 3 wires for a common feed set up, or 4 wires and break off fin for a separate feed set up
Customer: replied 23 days ago.
I was thinking I need to follow instructions for separate feed set up since I have 4 wires... no?
Expert:  Mike G. replied 23 days ago.

I can't tell you to wire a green wire for a hot wire. That's why you need to test and check the wire colors at the lights.

Customer: replied 23 days ago.
Ok. I will see if I can find a tester and let you know.
Expert:  Mike G. replied 23 days ago.

Very good.