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Kevin
Kevin, Licensed Electrical Contractor
Category: Electrical
Satisfied Customers: 3528
Experience:  30 years Licensed Electrical Contractor in Illinois, Adjunct College Electrical Instructor, Former Electrical Inspector, Diploma: Digital Electronics, FCC Technician License
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Black wire to ceiling lights and wall switches are hot but

Customer Question

Black wire to ceiling lights and wall switches are hot but lights don't work we are talking about 3 different lights controlled buy different switches?
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) What type of wall switches? Single pole ON/OFF snap type of switches or dimmer switches?

How many switches? Are the switches ganged together in 1 wall box or installed in separate wall boxes?

2) What type of light bulbs? Incandescent or CFL or LED or Fluorescent or Halogen?

3) Are you using an AC voltmeter to confirm the ceiling switched loop conductors are working correctly?

Did you measure from the switched loop to the white neutral at the ceiling with the switch ON & OFF?

Customer: replied 1 year ago.
All of the above. I tested the circuit breaker also. 1 light is on 2 switches. 1 light is on 1 switch. One light is on one switch in a gang box with 2 other switches that control two other lights. I tested all black wires by touching the metal box with the common wire of the meter and all types of bulbs are used except halogen.
Expert:  Kevin replied 1 year ago.

Thanks for the replies.

1) Do all of the lights reside on (1) one circuit?

2) At the ceiling box, temporarily disconnect the lights. What are the following voltage measurements under a "no load" condition at the ceiling box?

A) Switched loop (switch in ON position) to the White neutral

B) Switched loop (switch in ON position) to ground (metal box)

C) White neutral to ground (metal box)

3) Is this a new install or were the lights previously working correctly?

4) What type of switches? ON/OFF snap type or dimmers?

Customer: replied 1 year ago.
Are you still here?
Expert:  Kevin replied 1 year ago.

Yes I am:)

Customer: replied 1 year ago.
Ok
Expert:  Kevin replied 1 year ago.

1) Did you not receive my previous reply on the voltage measurements?

Customer: replied 1 year ago.
No I didn't. They were 120.
Expert:  Kevin replied 1 year ago.

Me

Thanks for the replies.

1) Do all of the lights reside on (1) one circuit?

2) At the ceiling box, temporarily disconnect the lights. What are the following voltage measurements under a "no load" condition at the ceiling box?

A) Switched loop (switch in ON position) to the White neutral

B) Switched loop (switch in ON position) to ground (metal box)

C) White neutral to ground (metal box)

3) Is this a new install or were the lights previously working correctly?

4) What type of switches? ON/OFF snap type or dimmers?

4 Jan 2016, 7:53 PM

I replied back to you 24 minutes ago. Need answers for the above.........Thanks............Kevin:)

Customer: replied 1 year ago.
All on 1 circuit. Black to white reads 0.9 to 1.1. Black to ground reads 120
Expert:  Kevin replied 1 year ago.

Thanks for confirming.

Just as I suspected, you have a loose neutral connection.

Measure from a white neutral to ground and you will have voltage there, let me know what it measures?

Customer: replied 1 year ago.
0.9 to 1.1
Expert:  Kevin replied 1 year ago.

Hmmm.... that seems too low.

Since the hot to neutral is showing almost 0 volts, the neutral to ground voltage should be much higher than .9 or 1.1 volts.

You sure that Hot to Neutral voltage is also .9 or 1.1 volts?

Customer: replied 1 year ago.
Hot to neutral is o hot to ground is 120
Expert:  Kevin replied 1 year ago.

And neutral to ground is .9 or 1.1?

Customer: replied 1 year ago.
Neutral to ground is 97
Expert:  Kevin replied 1 year ago.

OK, now we're talking:

1) You have an open neutral somewhere on the circuit.

A) H to N voltage should = approximately 120 volts, You have 0 volts.

B) H to G voltage should also = approximately 120 volts and you have 120 volts. Therefore, the hot and ground are both good.

C) N to G voltage should always measure 0 volts or very close to 0 volts. You are measuring 97 volts, therefore this confirms an open neutral.

2) Did you replace any lighting fixtures or undo any neutral splices in any boxes or replace any wall switches?

Customer: replied 1 year ago.
on other circuits not this one.
Expert:  Kevin replied 1 year ago.

Thanks for the replies.

1) I suggest going back to the other boxes and double check the neutral connections as there is an open neutral somewhere probably due to a faulty splice.

2) Is this circuit and the other circuit controlled by a double pole circuit breaker or 2 separate single pole breakers that are stacked on top of each other in the main panel?

Customer: replied 1 year ago.
I didn't do any splicing. Just replaced switches and outlets
Expert:  Kevin replied 1 year ago.

I understand, however when pulling devices out from wall boxes, an existing splice can easily become loose.

If any of the receptacles were wired using the back-stab insert holes, those are always prone to come loose. Devices should always be terminated to the side screw terminals and use pigtails as required.

If the lights were all working correctly prior to replacing the devices, then an open neutral resides in one of those boxes.

Customer: replied 1 year ago.
Ah while I didn't use back stab other outlets and switches did I'll have to get back to you tomorrow
Customer: replied 1 year ago.
Oh
Customer: replied 1 year ago.
The open neutral is on this circuit not another circuit?
Expert:  Kevin replied 1 year ago.

No problem, just reply back to me when you have an opportunity and we can take it from there.

Not sure, depends if the circuit was configured as a shared neutral circuit or if the lighting circuit has it's own dedicated neutral. Thus the reason I asked about the type of breakers and if they are stacked on top of each other. If the circuit is wired as a shared neutral, then somewhere there will be a split.

Customer: replied 1 year ago.
Talk to you later
Expert:  Kevin replied 1 year ago.

OK, have a good evening..........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:)

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