I ran into a weird electrical situation this morning. I got a call from someone who wanted a thermal scan of their electric panel. I went over there, and he told me and showed me how the lights throughout the house dim when almost anything in the house is turned on - even small loads like the garbage disposal.
He read online that this could be caused by a loose neutral, and that a thermal camera might be able to find it. I saw nothing unusual with my camera. Since I was already there, I did a little investigating. I plugged in my Suretest circuit analyzer to measure voltage and to see what happens with the voltage when various loads were turned on.
Here’s what happened.
With nothing on, the voltage was about 117
Turn the dryer on - voltage went as high as 135
Turn on deep fryer or garbage disposal - voltage up to 140 - 145
Turn on microwave (with dryer running) - Voltage dropped from 135 to about 120
The Suretest was plugged into a receptacle on the same phase as the deep fryer and the disposal, but opposite the microwave.
Obviously, its not my job to solve this for him, and I suggested that he call an electrician, but the engineer in me wants to figure out what is going on.
I made a video of what the Suretest was showing during all this, but don’t see how to post a video.