jaylectricity
Senior Member
- Location
- Massachusetts
- Occupation
- licensed journeyman electrician
Friend of mine complained of flickering and dimming lights at his house. Often when the heat kicked in, but also during other times.
Found many issues in his panel including a conductor on a breaker that was loose, had heated up and melted the insulation. Corrected that. Also noticed that just flipping some of the AFCI breakers on and off caused lights to flicker.
One such AFCI breaker was for the forced-air furnace. After investigation also noticed the furnace was on GFCI protection through the personnel GFCI receptacle at the unit.
Through various tests I noticed that phase A was giving 114V and phase B was 124V. When the fan motor of the furnace kicked in, there was a 10V drop that dimmed the lights for a second. The heat was initially on phase A. When I moved it to phase B, the lights didn't dim as much and the fan sounded much more efficient. But on both phases the voltage dropped by 10 at startup.
Other than the unbalance, the voltage held very steady for each phase, moving less than 3/10 of a volt in either direction for a full minute of testing.
Is this a power company issue or should I be looking for loose connections or improperly bonded neutrals? I advised him to turn off one breaker at a time for half an hour and take note of any improvement.
Found many issues in his panel including a conductor on a breaker that was loose, had heated up and melted the insulation. Corrected that. Also noticed that just flipping some of the AFCI breakers on and off caused lights to flicker.
One such AFCI breaker was for the forced-air furnace. After investigation also noticed the furnace was on GFCI protection through the personnel GFCI receptacle at the unit.
Through various tests I noticed that phase A was giving 114V and phase B was 124V. When the fan motor of the furnace kicked in, there was a 10V drop that dimmed the lights for a second. The heat was initially on phase A. When I moved it to phase B, the lights didn't dim as much and the fan sounded much more efficient. But on both phases the voltage dropped by 10 at startup.
Other than the unbalance, the voltage held very steady for each phase, moving less than 3/10 of a volt in either direction for a full minute of testing.
Is this a power company issue or should I be looking for loose connections or improperly bonded neutrals? I advised him to turn off one breaker at a time for half an hour and take note of any improvement.