With 40 years in the electrical industry, Technical background, then engineering, experienced in testing switchgear, power plants, generator paralleling systems, ground fault systems, power quality problem diagnostics, taught industrial motor controls and code for 14 of those years, presently managing technical support group for a 50+ member MEP design firm. Still teaching in the electrical commissioning field on a national level.

Point is, I have seen a lot, learned a lot, taught a lot and forgot a lot, but one thing that I have never forgotton is the lessons that I have learned from the experiences of others. The industry today is very fortunate to have computer communications, forums and the Mike Holt Newsletter to share these experiences and comments with others through.

If you are still reading this, the following describes a stray voltage or abnormal voltage condition That I had the opportunity of troubleshooting and finally located the source of. It is almost identical to the voltage problem in the shower that someone else posted and could not correct by adding ground rods.

My experience was finding 3 volts between the shower faucet and the tub drain screen in my own home 35 years ago. I only noticed it because of a cut on my finger which made it more sensitive to the low voltage tingle. Now I was sure that I had no ground issues since I had personaly completely rewired the older home we were living in at the time including a new service panel with two groung rods and a connection to a buried 3/4 copper water pipe that was copper from the street.

The following was done in an attempt to isolate the source either as being within the residence of coming from the utility. 1. Installed Simpson 260 voltmeter between tub faucet and drain--read 3 volts. 2. Opened the main breaker-- no change 3. Pulled meter---no change 4. Disconnected overhead phone service cable from house.---no change 5. Disconnected utility neutral from house---no change 6. Finally disconnected the utility messenger cable which was attached to the 2'' conduit service mast. ---zero volts. 7. Confirmed 3 volts between the disconnected messenger cable and the conduit mast. This was because the messenger cable is also connected to the utility primary ground and the transformer neutral. 8. Power company disconnected their transformer secondary neutral from the pole ground and the three volts was still present between the messenger cable and the service conduit mast. This next step in the trouble shooting was the most difficult and did cause at least some of my neighbors to question my intentions. It was evident by now that the source of the leakage voltage would be found at another service or residence nearby along this rural road and single primary line. (not so easy if it were in a sub division or if no one knows you.)

9. After calling several neighbors and asking each one to please turn off the main breaker to their own house which took lots of explaining, the voltage imediately dropped to zero when the main breaker was turned off at one house aproximately1/2 mile away.

10. Problem was further isolated by asking neighbor to turn main breaker back on and individually turning off each breaker (double poles first) until the voltage dropped again to zero. You guesed it right---The water heater was the source.

11. The next step was not able to be performed until after the neighbor's husband arrived home later in the day.---Bottom line is: There were two problems found that was causing the stray voltage. (a) First the upper heating element in their water heater had failed and burned a hole through the element tube which was connecting one hot leg directly into the water all of the time. Both hot legs were connected into the water when the upper thermostat reached the temp set point and switched the 2nd leg to the lower element. (b) Next, the service ground consisted of only one # 6 bare copper wire previously connected to a rusty pipe ground rod which had been severed by the man's lawnmower. He had made an attempt to reconnect it by wraping the wire around the pipe.

In summary, The voltage entering the water was seeking a path to return to its source (the utility transformer). There were several high resistance parallel paths for this voltage and current in this instance. the lowest resistance path was from the water heater through the copper cold water pipe to the street water main, through the earth and the street main to my residence via the copper cold water pipe which was bonded to the incoming utility neutral and their primary ground. The current followed the primary ground down road to the pole and transformer serving the neighbors house. The 3 volts that was appearing between the tub drain and faucet at my residence was simply the voltage drop found across one of the parallel paths that the current from the defective element was flowing.

So now you see we can call it a stray voltage or we can really cause some confusion and call it a voltage drop.

The final solution was: a. replaced both heating elements in water heater just to prevent a future failure. b. Verified neutral /ground bond was correct in panel. c. Installed new # 4 bare copper ground from panel neutral bar to 3/4 copper cold water with in 2 ft of its entrance and extended same unbroken to two new ground rods spaced 8ft apart. d. Bonded around the water pressure regulator and between the hot and cold water pipes under the house. (Today most inspectors will want this bond to be visible and near the water heater.)

I have only encountered this problem one other time since the first. It to was a defective element in the water heater however it was found in the same residence that was experiencing the voltage in the kitchen sink. The water system was copper within the house and some copper in the ground on the incoming supply. The water service from the street was 1" plastic. There was a ground rod and proper sized grounding electrode conductor, however the mechanical connection to the rod was loose and corroded. The fix was replaceing the element and repairing the rod connection with an acorn type connector.

I hope these comments will assist someone else with a similar problem.

Larry LeSueur CPQ, CBCP llesueur@barrettwoodyard.com 770-810-8800