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Electrical Wire and Cable

What Causes Lights to go Dim

dim lights

Summary: Electrical Lighting Question: In the basement of my house there is a electrical circuit with a 15 amp circuit breaker and 14/2 wire which powers four lights, a deep freeze, a heat exchanger and four other outlets.

What Causes Lights to go Dim

Why Lights Go Dim

In the basement of my house there is a electrical circuit with a 15 amp circuit breaker and 14/2 wire which powers four lights, a deep freeze, a heat exchanger and four other outlets.

The four other outlets are not in use. Occasionally, the lights will go dim.

What could be causing this problem?

Eric S.

Hi Eric - Great Electrical Repair Question!
Because the circuit is only 15 amps and you have a few considerable loads which include the compressor of the deep freeze, I would suspect that the dim lights that are being experienced due to the freezer compressor cycling on, especially if the heat exchanger is running. This can also be due to other major loads which are on the same buss back at the panel. You may want to consider installing a separate circuit for these two devices, especially you ever plan to add any additional loads to this circuit.
Hi Eric, Many times when you get a dim light this indicates a feedback, usually through the neutral. I'm not sure which tester you are using, possibly and induction type where it uses an internal coil and not electronic logic, so this will produce that reading with a feedback which is indicating a lower voltage. I would check your circuit. Make sure the ground is bonded at the panel circuit source and that this bond is continued at all junction box locations. At the location of the circuit it's a good idea to separate the incoming circuit, verify the readings, polarity etc. Then verify that none of the load side wiring is crossed up as to maintain correct polarity

Where half-hot switched outlets are used the neutrals can be bonded through so there is no need to break the neutral tie bar or jumper on the outlet as long as the circuit is the same source for both sides of the outlet. From: Eric S.
Thanks so much for your quick reply. I will certainly take your advice and put these devices on a separate circuit. I do have another Question: I just installed two split receptacles on a switch for the use of my lamps in my recreation room. As always I tested these receptacles and discovered on one tied to the switch, that when the switch is in the off position a faint light comes on my tester. This doesn't happen on the other receptacle THe top of these receptacles are fine. . I checked the situation and found the ground wasn't tied to the receptacle. Once I connected the ground and retested there was no light on my tester. Why would leaving the ground of the receptacle allow a little voltage on the switch side of the outlet when the switch is in the off position?
Thanks again, Eric
Dave Rongey, Licensed Electrical Contractor, Assisting with Home Electrical Troubleshooting and Electrical Repairs


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