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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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Lights dim in house when any appliance is turned on [dryer,garbage

Customer Question

Lights dim in house when any appliance is turned on [dryer,garbage disposal,dishwasher,washing machine,hair dryer. This started 2wks ago and we have not done any electrical work during this time frame.

What could be the cause


Submitted: 6 years ago.
Category: Electrical
Expert:  electrifier replied 6 years ago.
Chat Conversation Started
electrifier :

Hi there..... lets see if I can help you figure this out. Do you have a volt meter available?




hi are you still there electrifier?


is anyone available



Expert:  Mike G. replied 6 years ago.
Hi, I'm Mike and I'll be glad to assist you. The Electrifier is off line for some reason, so I'll fill in for him until his return. Is that OK with you?

Edited by Mike G. on 8/10/2010 at 1:29 AM EST
Customer: replied 6 years ago.
Expert:  Mike G. replied 6 years ago.
OK, let's proceed

1) Go to the panel. You'll need your tester and a flashlight.

2) Turn off all breakers except the main.

3) Take the following readings - on the incoming wires ahead of the breaker
  • Hot ot Hot
  • Hot #1 to Neutral
  • Hot #2 to Neutral
4) Remove a 2 pole breaker and take the same reading on the buss.

Let me know what they were.
Customer: replied 6 years ago.

hi mike i am not @ the panel it is my nweighbors house.


when i took readings earlier this evening i did not turn off the breakers but took reading

hot #1 to neutral 118v

hot#2 to neutral 118v

hot to hot 220v



Expert:  electrifier replied 6 years ago.
I'm back here now. Sorry for the delay here.
You say you had 118 volts to neutral on both legs but only 220 volts line to line? You didn't have about 236 to 240 volts?
Customer: replied 6 years ago.
it was closer to 240v
Expert:  electrifier replied 6 years ago.
Ok, good.
So when you turn on an appliance the lights dim. What happens to the voltage when you turn on the dryer for example? Test this at the main breaker terminals.
Customer: replied 6 years ago.

i am not @ my neighbors house where the problem is.

i won't be back there ti ltomorrow nite.


what should my reading be @ main breaker when i turn on dryer???

Expert:  electrifier replied 6 years ago.
The voltage should not drop when you turn on a load. If it drops much there is a problem. If it drops 2 volts for a second it's not so bad but if it drops 15 volts it's more of a problem. Then we look further for bad connections where a big load will make the voltage drop. It could be in the meter or the power company connections outside. We have to verify the voltage drop and see if it is on both lines or just one. Using the dryer, it's the biggest load, test line to line and each line individually to neutral.
Customer: replied 6 years ago.

i will check with load on tomorrow. thanks for your help. i need to get some sleep


thanks steve

Expert:  electrifier replied 6 years ago.
Good night. Catch you tomorrow night with results.
Expert:  electrifier replied 6 years ago.
Do you have the results for me yet?

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