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Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 7594
Experience:  Proven Professional 48 years Experience
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I have 3 black wires coming out of my box. I am trying to

Customer Question

I have 3 black wires coming out of my box . I am trying to replace the light switch and do not know which wire goes where. I have connected them and then it turns my breakfast room light on and not my kitchen light. It never controlled the breakfast room light before
Submitted: 2 years ago.
Category: Electrical
Expert:  Mike G. replied 2 years ago.

Do you have a 2 wire voltage tester?

Customer: replied 2 years ago.
Customer: replied 2 years ago.
No, I do not.
Expert:  Mike G. replied 2 years ago.

One of the black wires is the feed and the others are to the kitchen light and to the breakfast room. With all 3 connected together both lights should work, one without a switch. Put them together and then remove one at a time until the kitchen light goes out. Now check to see if the breakfast light is still on. If not, the wire removed is the hot. Let me know how it goes.

Customer: replied 2 years ago.
put them all together the black wires all on the same screw?
Expert:  Mike G. replied 2 years ago.

No put them together with a wirenut. You'll need a wirenut for the final connections. Only one wire under a screw and never use the pushback connections.

Customer: replied 2 years ago.
I just took off the 3 wires., I thought one is hot one is for neutral and one for ground. they didn't have a wire nut on them before
Expert:  Mike G. replied 2 years ago.

Hold on. The statement in your question said that you had 3 black wires. What do you have?

Customer: replied 2 years ago.
I have 3 black wires. There are 3 screws on the switch
Expert:  Mike G. replied 2 years ago.

Not having a tester to identify the hot wire, you need to put the 3 wires together and by elimination determine which is the hot wire. When together the lights should work. One will not be switched. The wire that when connected to either of the others allowing a light to work is the hot. When you find it we can continue. The alternative is to get a 2 wire tester