Dimming lights

[tbird]

I had a strange one today. The sellers have a load of clothes in the dryer. The dryer keeps cycling on and off (anti-wrinkle cycle). Everytime the dryer turns on, the lights dim. This is a 3000 square foot home and no matter where you you are, the lights would dim anytime the dryer would cycle on. The sellers says it has been like this forever. Does anyone know the possible cause.

200 amp service. 22 110v circuits and 3 220v circuits. The dryer is on a 30 amp 220v circuit. No evidence of overload at the wire connections in the panel. I am stumped.

Thanks for your help,

Carl Johnson

[Jim Katen]

I had a strange one today. The sellers have a load of clothes in the dryer. The dryer keeps cycling on and off (anti-wrinkle cycle). Everytime the dryer turns on, the lights dim. This is a 3000 square foot home and no matter where you you are, the lights would dim anytime the dryer would cycle on. The sellers says it has been like this forever. Does anyone know the possible cause.

200 amp service. 22 110v circuits and 3 220v circuits. The dryer is on a 30 amp 220v circuit. No evidence of overload at the wire connections in the panel. I am stumped.

Thanks for your help,

Congratulations, you've discovered voltage drop. I'll alert the Nobel committee.

There are three possible causes: a wire or wires that are too small; a wire or wires that are too long; or a loose connection. Since it's affecting all of the lights in the house, I'd tend to suspect a problem at the service panel or even at the service drop or lateral.

If it's a loose connection, there might not be any visual clue but the connection might be hot or warm. (Hint, don't touch it with your fingers to find out.)

A good electrician can chase this down.

- Jim Katen, Oregon

[Scottpat]

I found this on a home a few years back. It was like a 1975 Disco! Every time the washing machine would wash the lights would dim and get bright. Did you know the some models of washing machines have motors that pulse on and off while they turn the agitator! A loose neutral was the culprit.

I would not have found this if the owner had not been washing clothes while I did the inspection.