Several residents in a rural neighborhood were complaining of getting shocked around their yards and homes. The most noteworthy complaint was from a lady who was doing laundry in her basement utility room. The floor was wet, she was barefooted, and she was touching her washing machine when she got a bad shock. The utility Troubleman measured 12-16 volts at that location.
The area Troubleman did the usual Stray Voltage investigation and mitigation steps of checking all neutral-ground-bonds in the area and then checking all neutral splices on the primary feeder from that area back to the substation. No problems were found.
Engineering was then called for assistance. They observed that this neighborhood was served right off the 3-phase backbone from a substation only about 1 mile away. That and the magnitude of the measured voltage caused them to suspect a ground-fault as the cause of the problem, rather than the more typical high impedance neutral issues. With the help of two Troublemen, and a complaining neighbor who just happened to be a residential electrician, they began a typical search routine for a ground-fault. A temporary ground-rod (remote earth reference) was driven near an existing transformer ground of a complaining customer and a voltmeter was connected between the two grounds using clamps. The meter indicated 8-10 volts neutral-to-earth. They then coordinated with Dispatch and temporarily pulled the cut-outs on the complaining customers, one at a time, with no affect on the measured voltage.
The next step was to pull the cut-outs, one phase at a time on a nearby 3-phase tap. Two of the three had no effect, but pulling the third cut-out resulted in the measured neutral-to-earth voltage dropping to near zero. The cut-out was put back in service and the measured ?stray? voltage returned. That indicated that the suspected ground fault was on that phase somewhere on that tap. The Troublemen then pulled cut-outs on transformers down that tap until they found one that caused the measured voltage to drop to near zero when it was opened. That cut-out was closed back in and the meters served from that transformer were then pulled one at a time. This resulted in finding a meter for a mobile home that, when pulled, resulted in the measured ?stray? voltage dropping to near zero. The owner of that residence was identified by a neighbor who provided his phone number.
At that point the residential electrician neighbor, with the permission of the homeowner, opened the outdoor breaker box serving the mobile home and continued the trouble-shooting process to identify a single problematic branch circuit. He measured over 40 amps of load current on a 100 amp breaker, which was warm to the touch. That breaker served only a drop cord, which had been hard wired into the breaker box and was running exposed across the grass. It was traced across the yard, through a drainage culvert under the adjacent state highway, and down the river bank to a houseboat. It was being used to power a beer cooler refrigerator and a battery charger. The installation was obviously in violation of several safety codes. The homeowner was notified of our findings via phone call and the drop cord installation was removed from service via disconnection from the breaker panel. The voltage complaint problem was resolved. The homeowner then also mentioned that his most recent monthly electric bill had gone up nearly $300, and was happy that we had thus also resolved his high-bill complaint. The homeowner then inquired as to the proper procedure for getting an approved electric service installed to his house boat, by the utility.
