Electric shock from touching water from kitchen faucet

Status
Not open for further replies.
J

jeff48356

Senior Member
Location
Livonia, Michigan
What would cause the water faucet, pipes, and water to become electrified from the kitchen sink? I remember this happened in 1992 in a house built in 1942. The house had galvanized steel water pipes. Wiring was cloth-covered NM cable. I haven't experienced it recently, but what would be a possible cause and remedy?
 
My BIL was pretty reclusive so I was surprised when he called me about getting shocked while bathing. First was no water pipe bond. Second was a tapped splice that was directly on the pipe. Old friction tape. Faucets and handles were not mounted on the old cast iron tub so they were at different potential. I managed to force a piece of cardboard between the pipe and splice removing the voltage. The shock must have been substantial because he allowed me to come back with proper repairs.
 
LarryFine said:
First suspect is a bad service neutral. Compare line-to-neutral voltages.
Click to expand...
Just out of curiosity.. are you prioritizing this because with a faulty system neutral, the current is trying to find the source and potentially utilizing some of the water pipes?
 
ptonsparky said:
The remedy is to bond all the metallic piping systems to the grounded conductor at the SE. Not just the water pipes. Many older homes had cast iron and galvanized drain lines. Some in our area had copper. You need those at the same potential, or you may feel the difference.
Click to expand...
Essentially, yes.. but you're not bonding the the water pipes at the service. I feel like this could be misconstrued by the less experienced of us into thinking you have to run a conductor from the water pipe to the panel.

You're (1) bonding the GEC to the neutral at the service, (2) the GEC to the water main at the interior system ground, and (3) the hot and cold water pipes (and the gas) together at the boiler. That's how you get equal potential.
 
Jerramundi said:
Essentially, yes.. but you're not bonding the the water pipes at the service. I feel like this could be misconstrued by the less experienced of us into thinking you have to run a conductor from the water pipe to the panel.

You're (1) bonding the GEC to the neutral at the service, (2) the GEC to the water main at the interior system ground, and (3) the hot and cold water pipes (and the gas) together at the boiler. That's how you get equal potential.
Click to expand...
Do it however you want. We tap off the GEC to whatever piping system needs bonded as it goes past. Nothing says we cannot take each to a common bar.
 
In Michigan, our grounding system consists of a continuous ground wire going from the panel to two ground rods, and another continuous wire from the panel all the way to the water meter, and bonded across the meter. #6 is used if the service is 100 or 150A; #4 if 200A.
 
jeff48356 said:
In Michigan, our grounding system consists of a continuous ground wire going from the panel to two ground rods, and another continuous wire from the panel all the way to the water meter, and bonded across the meter. #6 is used if the service is 100 or 150A; #4 if 200A.
Click to expand...
Do they have this in a formal written code or is it just the way it's expected?

Roger
 
jeff48356 said:
In Michigan, our grounding system consists of a continuous ground wire going from the panel to two ground rods, and another continuous wire from the panel all the way to the water meter, and bonded across the meter. #6 is used if the service is 100 or 150A; #4 if 200A.
Click to expand...
Ours is the similar. Except, we don't typically go from the panel to the rods. We go from the meter to the rods.

Either way, I wasn't trying to take us off track into discussions about how to properly do the system grounding and bonding...

I was merely agreeing with @ptonsparky about the need to for equal potential bonding... and attempting to make a minor clarification for less seasoned readers that these other systems, in my experience, aren't "bonded at the service," but that the bonding occurs elsewhere and eventually connects to the system neutral via the GEC.
 
This is an interesting one because I'm trying to think about how I would troubleshoot it. I like @LarryFine 's suggestion about checking the system neutral first because if that's bad, the current is going to either (1) try to find another way back to source, which may be via the water piping system or (2) revert to ground, which may be via the water piping system... Correct?

Is there a consensus that the system neutral would be the first thing to check??
 
Jerramundi said:
This is an interesting one because I'm trying to think about how I would troubleshoot it. I like @LarryFine 's suggestion about checking the system neutral first because if that's bad, the current is going to either (1) try to find another way back to source, which may be via the water piping system or (2) revert to ground, which may be via the water piping system... Correct?

Is there a consensus that the system neutral would be the first thing to check??
Click to expand...
Neutral is a good first place to look. pull the neutral conductor out of the lug to be fully certain that it is corrosion free. I have also seen a hot water heater in a crawl space cause arcing under a kitchen sink.
 
Could be the neutral, but could be an ungrounded water heater or any other appliance connected to water with a fault in it. Turn off breakers one by one to see if voltage disappears, if only one breaker affects it, probably a fault in an appliance on that circuit. If it is multiple breakers, neutral would be suspect.
 
Without the bonding between metallic water piping and metallic drains, you may have a potential difference with no faults at all in the electrical system.

If there is any current flowing through the earth, the non bonded pipes act as conductive paths to bring the two different earth potentials close enough that a person can touch them.

People sometimes get shocks from hose bibs to the soil for the same reason. The hose bib is at the potential of the grounding electrodes and the soil that they are in, not at the potential of the soil near the hose bib.

If there are high resistance faults to the water piping (eg a faulted water heater element) then bonding can hide this fault. Bonding makes the shock go away but the fault causes current to flow via the egc back to the neutral.

-Jon
 
Status
Not open for further replies.
Top