Problem with voltage on kitchen sink

ElPuma07

Member
Location
Las Vegas
Hello so a friend of mine has been having some problems with his kitchen electrical. They get shocked occasionally on the sink and the hoses hanging from their faucets will arc out on nearby pipes occasionally. They've also had problems getting shocked by the washing machine. When the kitchen feed is on you can read 120v to the water in the sink. So I imagine when the old owners remodeled the kitchen something must have penetrated the water lines and is allowing voltage through them? I mostly do commercial stuff so the way these residential houses are wired seem pretty terrible. Wanted to know if anyone else had a similar problem before or a better idea than mine which is to take off devices one by one until I find the run that is the culprit. Thank you
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Hello so a friend of mine has been having some problems with his kitchen electrical. They get shocked occasionally on the sink and the hoses hanging from their faucets will arc out on nearby pipes occasionally. They've also had problems getting shocked by the washing machine. When the kitchen feed is on you can read 120v to the water in the sink. So I imagine when the old owners remodeled the kitchen something must have penetrated the water lines and is allowing voltage through them? I mostly do commercial stuff so the way these residential houses are wired seem pretty terrible. Wanted to know if anyone else had a similar problem before or a better idea than mine which is to take off devices one by one until I find the run that is the culprit. Thank you
Quick off the cuff guess...
See if the outlets are wired correctly.
i think you have no choice but to go the way your thinking...
maybe check them to the ground prong receptacle to verify they are wired correctly?
That would keep you from having to remove the,.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Copper water lines? They should be bonded to ground at the service so what you have can't happen. If they are not they could become energized. Check that out first.

Are the hoses you speak of flexible braided stainless steel risers under the sink that connect the faucet with the supply lines? And they arc when they hit the drain line?

Yeah, sounds like you have two problems- plumbing isn't bonded and there is a fault someplace that is putting voltage on the plumbing. Fix the first problem and see what breaker trips. :D

-Hal
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
When the kitchen feed is on you can read 120v to the water in the sink.
I see he already said which breaker. That would indicate the kitchen breaker and whatever is in that circuit.

What I'm wondering about is you are reading 120v from the water to where? Ground on a receptacle? Kind of unusual for water to be that conductive.

-Hal
 
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GoldDigger

Moderator
Staff member
A small comment on terminology. It is very unlikely that anything "penetrated the water lines" to energize them. Much more likely something penetrated the insulation of a wire and it touched a water pipe (which was not properly bonded!)
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Unless this is PEX and he thinks something is putting voltage on the water. That's why I asked if this was copper and the question about the water in the sink.

-Hal
 

ElPuma07

Member
Location
Las Vegas
Copper water lines? They should be bonded to ground at the service so what you have can't happen. If they are not they could become energized. Check that out first.

Are the hoses you speak of flexible braided stainless steel risers under the sink that connect the faucet with the supply lines? And they arc when they hit the drain line?

Yeah, sounds like you have two problems- plumbing isn't bonded and there is a fault someplace that is putting voltage on the plumbing. Fix the first problem and see what breaker trips. :D

-Hal

Yeah the hoses are the braided stainless and they would arc when they hit the drain line. The plumbing bond should be near the service if I'm imagining correctly?
 

ElPuma07

Member
Location
Las Vegas
It has been a while since I've tested this issue at his home but now I'm thinking the water lines aren't properly bonded either which would definitely be an issue.

When reading from ground to kitchen faucet/water in the sink I'd read 120v which would drop slowly as the water exited the sink.
 

kwired

Electron manager
Location
NE Nebraska
Yeah the hoses are the braided stainless and they would arc when they hit the drain line. The plumbing bond should be near the service if I'm imagining correctly?
Is the drain piping metallic? If so have you check for voltage between drain piping and water piping?

If it is relatively low voltage then one is not bonded and you are probably just measuring voltage drop on the service neutral for the most part. If it is at/near full 120 volts one of them is apparently faulted to an ungrounded conductor but is not bonded.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Yeah the hoses are the braided stainless and they would arc when they hit the drain line.
All you know is that there is a voltage difference between two points. You need to know which is improperly hot relative to earth.

Remember, you're dealing with a lethal situation here!

I would plug a cord into an unrelated receptacle (which should itself be tested with a solenoid or other low-impedance tester) such as laundry, and separately check the sink and the plumbing against each cord slot with the above tester. One of the two will test as hot to the cords ground, and will show either 240v or 0v relative to the cord's hot.

Also, the tests to the cord's neutral slot should mirror those to the cord's ground. You'll be affirming the house's neutral-ground bond by confirming that the laundry receptacle itself tests correctly, as well as the cord's neutral and ground are at the same potential, i.e., 0v to whatever true earth reference you can confirm.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Is the drain piping metallic? If so have you check for voltage between drain piping and water piping?
EIPuma07 said:
When reading from ground to kitchen faucet/water in the sink I'd read 120v which would drop slowly as the water exited the sink.
The sink is porcelain or another non-conducting material, right?
I think that because your meter is high impedance you are seeing that voltage on the water. Don't worry about the water, test between ground and your water lines and the drain line.

-Hal
 

gar

Senior Member
190921-0939 EDT

EIPuma07:

I have previously scanned the comments, but don't remember the details. My following comments take a path starting at the main panel.

1. Is the plumbing conductive pipe, copper or galvanized?

2. Is there any possibility that plastic piping has been inserted somewhere?

3. I expect the main panel has a neutral bus, and a separate EGC bus. Measure the voltage difference between these two buses. This should be less than a millivolt, or only a few millivolts.

4. Connect a long wire or extension cord to the neutral bus in the main panel to serve as a long test lead. Also look to see if there are any subpanels.

5. Make all measurements relative to this neutral bus.

6. Make voltage measurements to many places using a high impedance meter, 10 megohms input, looking for abnormal values.

Incoming water line. House side of water meter. Hot and cold water pipes in random locations. Gas piping. The conductive housings (cabinets) of various electrical appliances. A screwdriver stuck in the earth outside. The EGC terminal of various electrical outlets, and its associated neutral. Whatever is easy to test in the kitchen. Drain piping system. Your water stream experiment from close to the water spout, down the stream, and to the water drain. Hot water heater especially if it is electric.

Somewhere you will find abnormal voltages. A 10 A load can produce up to several volts on a neutral that is measured near the load.

See what you find.

.
 

kwired

Electron manager
Location
NE Nebraska
The sink is porcelain or another non-conducting material, right?
I think that because your meter is high impedance you are seeing that voltage on the water. Don't worry about the water, test between ground and your water lines and the drain line.

-Hal
Non metallic sink maybe, drain fitting usually is metallic. Though I haven't seen "hot water" from this I have seen water that is grounded well enough through this that any "stray voltages" imposed on the water line are felt in a sink, tub or shower a few times before, but to the user it don't matter which side is "hot" there is still voltage between the water supply line and the drain.
 

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
Is there a garbage disposal below the sink? If so, completely disconnect it electrically to see if the problem goes away. If it goes away then check the unit for isolation between the hot and neutral leads to the housing by measuring resistance with a meter.
 

gar

Senior Member
190921-1146 EDT

EIPuma07:

This morning with whatever loading I may have I read 0.2 mV from one end of the main panel neutral to the other end. Half way along the bar it is 0.1 mV. From neutral bus to EGC bus about 0.5 mV. Frome neutral bus to water meter 1.5 mV.

Next to kitchen.

At an outlet within 1 foot of the sink I read 197 mV neutral to its EGC. Same outlet EGC to disposal ring 30 to 50 mV varying. Same EGC to sink faucet 8.5 mV quite steady. Sink tub to disposal ring 0.0 mV.

With breakers to both the dishwasher and disposal off the faucet to sink is a steady 26 mV. Same when dishwasher breaker is on. But when just the disposal breaker is on there is the fluctuating low to 50 mV variation. The switch to the disposal has an internal neon bulb that is 53 years old and does not remain on steady when the switch is off. I am surprised that the small neon current, possibly 120/100,000 = 1 mA would cause that much voltage variation between sink and faucet. Also seems to imply that faucet to sink is somewhat insulated. That I don't expect. If I unplugged the disposal I would expect the same as the breaker being off.

These are just some measurements for you to use for comparision.

.
 
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