DC Current on Sink in Kitchen

Trackbuddy

New member
Location
Nampa, Idaho
Need some help
At a friends place his girl friend gets shock at least twice a day from the kitchen sink. With power on in the house he reads .32 vdc on a digital meter to ground. Turning all power off at the main he still reads .32vdc on his meter. We have checked every thing and are at a loss to were it is coming from, Open for suggestions Thanks:?
 
Last edited by a moderator:

ptonsparky

Senior Member
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
Electrical Contractor
IIRC from "stray voltage" @ dairys, .32 volt is getting to the limits of what most of us can detect. Cows are about .5v but they usually have more points of contact than humans and they are wet.

What is she touching when she feels this shock and how long is the shock sustained? Is she willing to hold on while you put a meter across her points of contact to determine voltage under load?
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
What does the meter show when set to read AC? If she puts her fingers across the ends of a D size battery can she feel the voltage? I think it would be rare for a person to be able to feel 0.32 volts.
 

electricalist

Senior Member
Location
dallas tx
In plug the disposal. Then disconnect the hot water under the sink. Then disconnect the cold water. If that doesn't lead you to something ground the sink?
 

Besoeker

Senior Member
Location
UK
What does the meter show when set to read AC? If she puts her fingers across the ends of a D size battery can she feel the voltage? I think it would be rare for a person to be able to feel 0.32 volts.
I agree. Maybe we don't have the whole story.
 

charlie b

Moderator
Staff member
Location
Seattle, WA
Occupation
Electrical Engineer
Odds are that she touches the sink far more often than twice a day. So I would approach the situation from the perspective of, "why does she not feel a shock the other times?" For example, does the shock happen only when,
- The dishwasher is running?
- The disposal is running?
- The hot water is running?
- The cold water is running?
- No water is running?
- The sink has water in it?
- She is also touching the toaster?
- She is using the sink's hose to fill the coffee maker?

I would suggest speaking with her, and getting her to try to remember the details of the times she felt a shock. In the meantime, I would suggest to her (and to your friend) that before doing anything with the sink, touch it first with the back of your hand. The reason is that if the shock takes place, it will cause the hand and arm muscles to contract, thereby pulling the hand away from the sink. I might also suggest to your friend that if he wishes to keep this person as his girlfriend, that he start volunteering to do the dishes. :lol:

 

electricalist

Senior Member
Location
dallas tx
Auto correct.
If there is voltage on the sink and it stops shocking her when it's connected to an e.g. then it might help determine the cause or if nothing else not shock her. 32 volts is pretty low.
 

cadpoint

Senior Member
Location
Durham, NC
Is this an apartment complex? Do they have motion water dispensing?
Does she walk around with rubber flip flops? I do most of the year and I
get zapped pretty good on SS counters...
 
Last edited:

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
I can wave my meter probes around in the air and read .32VDC...

Oh and just to be pedantic, you are measuring a DC VOLTAGE potential, not DC current. Your meter would have to be in series with the woman and the sink to be able to read current.

I too think this is much more likely to be static discharge. Winter time, dry air, vinyl flooring or laminate flooring will make that worse. I put some of that fake wood looking laminate flooring in my kitchen a few years ago and now when it's dry outside, I get zapped almost every time I touch the sink.

That's why I tell my wife I'm not doing the dishes... :angel:
 

factoryrat

Member
Location
Detroit
This topic reminds me of an electrical shock I used to get.

This topic reminds me of an electrical shock I used to get.

This reminds me, when I was a boy, of a shock we used to get in our kitchen when a light switch was turned ?ON?. My mother and I complained to my dad about the shock we occasionally received and he would just laughed it off; he never got shocked and I don?t think he really believed we were getting ?poked?.

My mom and I had to lean over an electric stove and usually put a hand on its metal frame to reach the light switch. My dad was taller, with longer arms and didn?t have to touch the stove to turn light on.

Finally one day he got out his voltage meter and showed me how to use it. It was old wiring in an old home and we discovered the switch bracket (yoke) became hot when switch was "ON". There was no ground wire in the romex. The switch had a plastic cover; but the two screws that held it on the switch were metal. Thus the small screws were "hot" and the metal stove was grounded and we got the ?poke? when we came in contact with both. We changed the wall switch with a new one and there was no voltage present on new switch yoke, switch plate mounting screws, and no more shocks after that.
 

mgookin

Senior Member
Location
Fort Myers, FL
I'm with those who say a human can not sense 0.32VDC. I wonder if she's taking a static discharge and then someone comes along and measures 0.32VDC which is present in any conductive material that's warmer than absolute zero.

While setting up cash registers in a buddy's business we were sorting the 12VDC cash drawers from the 24VDC cash drawers and with no vom so we just "tasted" the control signal voltage to pair the drawers with the requisite terminals. Worked great!

Even on your tongue I don't think you could sense 0.32vdc.
 

big john

Senior Member
Location
Portland, ME
Worked a similar call once for a bootleg ground on the kitchen receptacles: It was putting neutral current on all the grounded appliance frames.

With wet hands from washing dishes significantly reducing their skin resistance, people would get a little buzz when they touched any appliance and the well grounded sink.

I only measured a few volts between them, but it was enough to be felt. I'd be really impressed if someone could reliably feel half-a-volt though, especially since the threshold of perception is lower for DC than it is for AC: I would wager there's something else going on.
 
Here is one that I ran accross that was similar except it was the shower. The service was bonded to the copper water pipes, as it should. The home had a well with plastic pipe to the bladder tank. There was also ground rod or rods, but they will not carry much current. The home had a bad neutral from the utility which had the voltages out of wack, ground rods would only carry about 5 amps. I diagnosed this problem and then the lady told me of the shocks she would get at the shower. This home had metal drain piping which led to metal sewer pipe which went under ground. I measured about 70 volts between the water valve at the shower to the drain grate. Double checked it with my knopps and it was enough to move the solenoid. Once we got the neutral fixed the problem went away. I have been a believer in bonding the n metal drain piping to the metal water supply lines since this. This is never enforce in our area, in fact I have had inspectors ask me why we do it. I believe the code could be interpreted to require it since it says any metal piping system which travels 10 feet or more into the earth. ( not looking at the NEC at the moment). With the system the way it was, there was a potential from the supply line and the drain line, only when the loads on each leg were unbalanced with each other.
 
Top