garbage disposal trouble

[jdale672]

The problem: when the garbage disposal is turned on it creates a surge, ie. lights brighten and voltage goes from 120 to 125, then a big draw, ie. lights dim and voltage drops to 115. This effects the whole panel. Equipment: 1/2 HP 120v 6.9a badger garbage disposal. Dedicated circuit, steel flex, ground wire properly installed, disposal is installed as plug and play

 

[GoldDigger]

The problem: when the garbage disposal is turned on it creates a surge, ie. lights brighten and voltage goes from 120 to 125, then a big draw, ie. lights dim and voltage drops to 115. This effects the whole panel. Equipment: 1/2 HP 120v 6.9a badger garbage disposal. Dedicated circuit, steel flex, ground wire properly installed, disposal is installed as plug and play

Look first for an undersized or poorly connected neutral if the GD receptacle is on an MWBC.
Try measuring neutral to ground voltage at the outlet as the GD is turned on and off.
If all of one phase of a 120/240 panel goes down in voltage and the opposite phase goes up at the same time, look for a high resistance in the service neutral from POCO.
If both sides go down together, there is a problem with the service, and/or maybe the GD is pulling too much current for some reason.

 

[James S.]

The problem: when the garbage disposal is turned on it creates a surge, ie. lights brighten and voltage goes from 120 to 125, then a big draw, ie. lights dim and voltage drops to 115. This effects the whole panel. Equipment: 1/2 HP 120v 6.9a badger garbage disposal. Dedicated circuit, steel flex, ground wire properly installed, disposal is installed as plug and play

Ran into this a while back and turned out to be that the whole grounding bar in the panel was loose.

 

[kwired]

Sounds like a problem on feeder or service neutral to me.When disposal motor is starting it has a low impedance and will have less voltage drop across it, if neutral is bad this means the higher impedance lights will be in series with the GD motor and there will be more voltage across lights in this condition. When motor is up to speed its impedance does increase which will then increase voltage drop across that portion of the series and than lower the voltage across the lights.

If lights would be on same line (phase) as the motor then you would have the opposite result, lights would dim when motor is starting and would brighten when it is up to speed.