I just finished replacing a storm damaged feeder. The original feeder was lost to the hurricane we experienced here in the North East last year. In addition to replacing the 200 Amp feeder my contract called for me to megger test the existing dock wiring. While performing the testing we found that someone had installed a jumper between the neutral terminal and the equipment grounding terminal of one of the 50 Amp, 120/240, dock mounted power stations. Knowing that this jumper should definitely not be there we removed it. Now one of the boat owners is complaining that his power monitor is showing some kind of wiring fault. We temporally put the jumper back in for testing purposes and the wiring fault clears. I asked the boat owner if this was the 1st time the power fault indicator was active. He explained that when the dock was installed about 4-5 years ago, his power monitor did display a wiring fault. He called the electrical contractor whom did the wiring installation. The contractor told him "I know how to fix this", I be- leave the contractor installed the jumper, Apparent problem solved. But now we have whats not only an NFPA 70 violation but also a recipe for disaster.
With the jumper installed we now have a parallel path for current flow. One path is through the neutral conductor (as it should be) and the other path is through the water and earth (undesirable).
I will be performing a battery of tests tomorrow. I was just hoping that one you guys has been down this road before and could offer me some advice.
I have composed a list of questions I hope to get answers to:
1) what are these power monitors looking for
2) do different power monitors look for different things
3) do they check polarity
4) do the measure the voltage between the grounded & grounding conductor.
5) do they place a temporary load (then a measurement) between the grounding conductor and a phase conductor
Any help would be greatly appreciated
