Reminder to be safe with electricity
I just picked up a new employee a couple of weeks ago. His experience is in sheet metal and roof penetrations. Those are both areas at which I am weak. So, he is a great addition to our skill set.
I have been talking to him about visually assessing each job for safety as we walk up. He was about to lean on a package unit last week, and I told him to stop before he touched it because I saw a problem with the disconnect.
Yesterday, we had a call from a homeowner who had bought the home about a month ago. They where planning to have a birthday party for their three year old in just a couple of hours. Her father-in-law had tried to get the condenser unit running the night before without success. So, when we got there the disconnect was already pulled, and the electrical access panel removed.
It might have been an ICP NAC060, but the nameplate was virtually unreadable.
I checked for voltage on the unit anyway.
The father-in-law had replaced the dual run capacitor and wired common from the contactor to the HERM terminal, and compressor conductor was on the C terminal. Okay, simple fix, but I told my new employee that we needed to carefully check everything else before we restored power.
There was an old transformer in the condenser unit. The low voltage conductors were isolated under wire nuts. It was no longer being used. The white line voltage terminal connector was stuck in a gap between metal panels. It was making contact with the metal panels.
I asked the father-in-law where this wire was when he started working. He said it wasn't connected to anything. So, he stuck it between the panels to keep it out of the way.
The black line voltage conductor to the transformer was still connected to the line-in side of the compressor contactor.
Now, tell me if I am wrong.
If we had energized the unit, without removing this old transformer, the black lead would have energized the the transformer with 120V to ground. The ground being the condenser cabinet and the line set to the indoor unit. This would not likely have tripped a breaker because the potential would have been through the transformer as a load (unless the transformer was already shorted to ground).
I don't know how likely it would have been that any of the children at the party would have been hurt, but I do believe that it makes a good example of why it is important to continue investigating after you have found one obvious problem.
PS: The homeowner eventually produced the original capacitor that had been removed. It tested within 6% of its listed rating. I still don't know why the unit wasn't running before the father-in-law started working on it.
It's an upside down world we live in.