How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Kevin Your Own Question
Kevin
Kevin, Licensed Electrician
Category: Electrical
Satisfied Customers: 2936
Experience:  29 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector
71008832
Type Your Electrical Question Here...
Kevin is online now
A new question is answered every 9 seconds

I am replacing a smoke detector and the wires coming from

Customer Question

I am replacing a smoke detector and the wires coming from the ceiling are white and red, no black. I have a white, red and black wires in the detector
Submitted: 1 year ago.
Category: Electrical
Expert:  Kevin replied 1 year ago.

Hello and welcome to Just Answer. My name is ***** ***** I will be happy to assist you with your electrical question.

1) The black wire in the smoke is for the hot wire. the white in the ceiling box and smoke is for the neutral wire and the red smoke detector wire is for the inter-communication wire to other downstream smoke detectors in the home.

2) Since the ceiling box only contains a red and white. The red house wire is your hot wire and needs to be spliced to the smoke black hot wire. And the house white neutral wire will be spliced to the smoke detector white neutral.

3) Since your ceiling box does not contain an inter-communicated wire to inter-connect with other downstream smoke detectors, just cap off the smoke red with a plastic wire nut as it will not be used.

If you have any additional questions, just let me know and I’ll be glad to answer them for you.

Otherwise, don’t forget to rate me before you log Off.

Thanks..............Kevin:)

Customer: replied 1 year ago.
There is a black wire just passing through the box, no connector, unbroken, and the previous smoke detector was just hanging by one wire. Should I cut the black wire and attach both ends to the new black wire on the new smoke detector and attach the red wire to the red and the white to the white. This building was built in 1978 and I am doing the updating. (That is cause for concern right there).
Expert:  Kevin replied 1 year ago.

1) Since you are replacing the smoke detector and there was a previously installed detector, wire the replacement model to the same existing house wires that the original one was connected to. Refer to the wiring from my previous reply. The original smoke required a minimum of 2 wires if 120 volts.... ie....... a hot and a neutral. If only 1 wire connection on the original smoke, it obviously was not working on 120 volts?

2) No, DO NOT cut the black wire that is passing thru the box as that wire is either being used for another circuit or possibly being used for a different application.

If you have any additional questions, just let me know and I’ll be glad to answer them for you.

Otherwise, don’t forget to rate me before you log Off.

Thanks..............Kevin:)

Expert:  Kevin replied 1 year ago.

If you have any additional questions, just let me know and I’ll be glad to answer them for you.

Otherwise, don’t forget to rate me before you log Off.

Thanks...............Kevin:)

Related Electrical Questions