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Electrical Issues in shop & resolution

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  • Electrical Issues in shop & resolution

    Maybe this will help others diagnose a situation if they have similar problems. Electrical work is not my favorite thing to do.

    About a year ago, when equipment I've wanted for years started to become available & affordable at the same time, I started having electrical problems in my shops. Not consistent or easily repeatable. My service is 200 amp 240V 1ph power to a meter & panel in studio, with dedicated 100 amp service then directed to panel in each two neighboring old buildings. Recently, I've also had to replace the starter capacitor and then the magnetic starter coil on my 220V 1Ph primary compressor. Both had ruptured and failed.

    Other matters needing address didn't leave me much time to identify or resolve the problem. It seemed that old wiring work done decades ago by the previous owner was the problem in the two separate buildings. It isn't awful or bad work, just typical back yard shop work done by a handyman vs a licensed electrician. Last summer, a friend suggested I tighten all connections on the breakers and in the panel. I did after finding several breakers had connections that were loose. Some could be tightened approx one full turn after not having been touched for about 16-17 years. That did seem to make a difference, but the problems still persisted. I worked around the problems with drop cords and different circuits as needed.

    I have been budgeting time and money towards some upgrade work so I can move forward with getting my 3ph machines operating and fix/upgrade lighting as well as fix & resolve this ?? electrical problem. This week I finally had time to focus upon it when the power died again while doing some wood lathe work. Power came and went like normal. This time I was able to identify the problem and trace it. The main entrance was providing 122V-123V on one branch and 24V on the other... approx 145V total 1ph power instead of approx 240V 1ph. Not cool. Called the power company. They came almost immediately, <30 minutes. The technicians started testing and assured me it was likely a problem with the buried entrance, even though I suggested it may be a problem in connections at pole. Nope. Ended up being traced back to a corroded connection inside the transformer on the pole at the street. They disassembled & cleaned all with a wire brush and reconnected everything. Now I have 124V on both feeds for a total of 248V 1Ph power.

    I expect this low voltage was the reason for my capacitor and starter coil failures on my compressor and that a $$$ VFD would not have been happy with intermittent significant voltage loss on one leg as was happening. Thankfully it didn't happen while I was using my big welder, either. I also found that the suspect circuits of old work had been wired into the new panels in each building by me to connect by simple coincidence to the same low voltage bad leg. Nothing wrong with them, even though they'll still be upgraded.

    Now I can move forward with VFD and any phase convertors for my machines.

  • #2
    Do they have insurance to replace any damaged equipment?


    • #3
      There is a process for that. I have two accounts, one to house and one to shops, plus the neighbor's house, that are all supplied from that same transformer. Haven't talked with the neighbor yet. We also lost our refrigerator one day last fall. It was getting challenged, but during covid when there are few refrigerators left in stock or warehouses anywhere is not a great time to go shopping.

      Problem is everything that died was at least 15 years old, so I'm not confident that there will be much recourse or actual reimbursement if it's pro-rated. We'll see.