A Website on Maintenance of Electrical Systems

When I began my career as an electrical technician my first challenge was the problem of checking the continuity of a wire that spans a long distance. My problem was compounded due to the physical layout of the wire under test. Let me use a simple picture to layout the nature of my problem. A bunch of Armoured cables outgoing from the  PCC (Power Control Center) in Building 1 feeds a group of distribution panels in Building 2 over 100ft away. Ideally, the cables should be tagged but due to aging and poor maintenance, most of the tags were not visible.  The problem was that some Distribution boards in building 2 had power while some others didn't.  The DB of interest didn't have power and thorough checks showed that there was no power on the cable feeding that DB.   All outgoing cables from Building one PCC had power so I suspected that the cable was no longer continuous. Anyway in the initial design of the facility 3 spare cables was laid underground but without tag

Normally when you are called in to troubleshoot a trip or in my case, the complaint was that they receive a serious shock if any appliance with a metallic part is plugged into the power outlet (receptacle).  Even when they plug in a laptop to the receptacle all screws on the laptop effectively become a naked wire charged with 220V although it doesn't damage the laptop.  The first thing I did was to open up the power outlet and took voltage measurements of phase-to-neutral got 220v as expected, neutral-to-ground got 220v to my surprise, and phase-to-ground got 6v.  My first suspicion was that the electrician swapped phase and neutral wires, but I carried out further checks just to be sure I went to the distribution panel. I powered off the panel and performed a continuity test between the neutral and ground and I got a beep. Now I switched off the MCB that feeds the circuit and performed another continuity test between the neutral and ground this time no reading. T