I'm experiencing the classic symptoms of a bad or lost neutral and want to determine if the issue is my responsibility or the utility's. Voltage fluctuates plus or minus 6 volts when a large 120V load is placed on either leg of my service panel. I noticed that my lights would briefly dim when the boiler of my 1500w espresso machine cycles on, then they would briefly flicker when it cycled off. The dimming and flicker is consistent for any high-draw loads (vacuum, toaster, microwave).
I can also hear a feint crackling sound right behind my service entrance neutral when one of these loads is on. I presume this is arcing, but I can't see where it originates. I put a clamp-on ammeter around the main neutral and the ground conductor (connected to water entrance, transitions to PEX after). The majority of the current is on the ground conductor.
I noticed that the electricians that wired my home (built in 2017) didn't use the knockouts on the main panel, but rather drilled their own holes to put nm clamps through. There were a fair amount of metal shavings all around the neutral conductor.
The connections to the main lugs appear to be very tight. I systematically turned off each breaker while monitoring the current on the ground conductor and there was always current on it in parity with the load on whichever breaker(s) were still on. Are there any other steps I can take to determine where the problem lies? I'm in the US.
The utility company came out and initially thought everything was fine. I explained that I pretty much eliminated any neutral issue from the service panel main breaker on down. I insisted that he check the connections in my side of the meter and he found that both the neutral and ground were ‘very loose’ so he tightened them a few turns. I put a clamp on the ground wire in my panel and now I’m reading between 0.5 and 2 amps. Worse than zero, but better than the 40 I saw yesterday. The main neutral is now carrying most of the difference between the two legs. No more flickering or dimming lights under any loads and my voltages are pretty much even, only fluctuating between 121 and 124 volts, regardless of loads. I’m going to have to call them again tomorrow to remove the seal on the meter base to give me access to the terminals so I can fully tighten them.
Also, sorry about the unclear picture. It is looking straight down at the main neutral lug. Some debris is visible. The alt text poorly explained some of that.