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electrifier, Master Electrician
Category: Electrical
Satisfied Customers: 1633
Experience:  Electrical contractor and electrical inspector for over 24 years with phone and networking expertise
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MY lights get bright, then dim when the furnace motor, or the

Resolved Question:

MY lights get bright, then dim when the furnace motor, or the microwave, refrigerator etc. come on. Can you tell me what the problem might be?
[email protected] Thanks
Submitted: 7 years ago.
Category: Electrical
Expert:  electrifier replied 7 years ago.
Do you have a meter for testing voltage? Digital or analog will work.
Customer: replied 7 years ago.
I have a multi-tester. Is that what you mean?
Expert:  electrifier replied 7 years ago.
Yes it is.
Would you take the cover off the electrical panel for your house and test the following for voltage?
Input of main breaker line to line. What does this read?
Each line side terminal of main breaker to the neutral (white) conductor.
Test the breaker for each of the devices that gets brighter and dimmer when things start and stop.
Report each of these readings to me please so I can start to analyze your situation.
Customer: replied 7 years ago.
I am sorry I took the face panel off, but I don't understand what lines you mean. I am not very knowledgable about electricity. I don't see the neutral conductor. I will probably have to have an electrician come out. I guess I was trying to find out if that was necessary, or if it could be the transformer on the pole.

Thank You
Expert:  electrifier replied 7 years ago.
Your panel has a main breaker.  There are 3 large wires that come to the panel, 2 to this breaker, from the meter outside.  The 3rd wire is the neutral wire and terminates on one side or the other normally.  Set your meter for volts AC for at least 250 volts.  The wires from outside are called the line side of the breaker.  The load side is where the branch circuit breakers attach.
Hold the probes by the plastic and touch the metalic tips to the 2 terminals where the wires connect to the main breaker..  Let me know what you have there.
Customer: replied 7 years ago.
I don't know if you are online or not? I finally read enough and got enough nerve to test as you said. Your explaination really helped. I put the tester on ac 250 and the reading said just under 4 on the ac 10v line.

Thank You
Expert:  electrifier replied 7 years ago.
Is your meter digital or analog?
Customer: replied 7 years ago.
digital , it is just a little cheap tester
Expert:  electrifier replied 7 years ago.
You have to set it on 250 volts or more so it can read the voltage properly.
Which terminals did you test so far?
Customer: replied 7 years ago.
I have it set on 250 I tested both of the main wires & the 2 breakers in the kitchen and one in the main bath. I also tested the outlet in the bathroom.(my hair blow dryer doesn't seem to have the power it used to, and the lights get dimmer when I turn it on) they all read close to 4. If I read the line above that it reads 100.
Expert:  electrifier replied 7 years ago.
There are not lines to read on a digital meter. Digital simply displays numbers, there is no needle that points across lines.
ls it maybe an analog meter with the needle?
Customer: replied 7 years ago.
It is an analog meter. I'm sorry I must have given you the wrong info
Expert:  electrifier replied 7 years ago.
That sounds better.
Now testing across the 2 main wires coming into the breaker in your panel what do you read on the 250 volt scale?
Customer: replied 7 years ago.
Expert:  electrifier replied 7 years ago.
Ok, that's good.
Now test each one individually to the neutral in the panel. This is where the white wires connect. Give me the results of each of these tests.
Customer: replied 7 years ago.
one reads at 100 the other reads at 77

Thank you for your patients!
Expert:  electrifier replied 7 years ago.
So you have 225 volts across the main but each of them to neutral reads something funny. Each one should read 120 or something similar. The 100 might be close since it's analog but the 77 is a problem. I suspect a bad neutral connection in front of your neutral test point. I would start by calling the power company and telling them you have imbalanced power coming into your house. They will send someone out to check the connections, etc. You might have a bad meter socket, a bad connection where their drop connects to the wires on your house.
After they check things out and hopefully fix things let me know what's going on. I'll be here off and on.
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