Voltage at kitchen sink.

[220/221]

I was at a residence today starting a service relocate when the customer came out and asked me if I could take a look at a problem. She is getting shocked off her cast iron kitchen sink.

I pulled off of my task because these types of calls seem extra dangerous to me. I once had 120V coming off my own shower plumbing and I have seen 120V a couple other times on the plumbing.

I checked between the drain and the faucet and g0t 20 something volts. Not enough to kill her....yet. Old house wired primarily with BX.

One of the issues is finding which direction the voltage is coming from so I strung a ground wire outside and attached it to the panel. I read 22 volts from the sink/drain (other lead on the fluke is attached to the ground wire)

I found the offensive circuit originating in this panel (a whole nother post)

and there was obviously a JB in the attic somewhere as all 3 original receps on the circuit had only 2 wires in them.


I took apart some handymans work from the 60's (disposal switch under the cabinet) and cleared the sink voltage. I found this mess and temporarily corrected it, thinking the problem was the broken wirenut contacting a ground wire.

Nope.

I found that when I disconnected the dishwasher feed, the voltage went away.


Pulled DW all the way out (no acces to the wiring) unpluged it and the volts went away. Hmmm....bad DW???...somehow leaking voltage ??? Obvious factory cord (never seen that), no visable JB.


I plugged a small microwave into the DW recep (which some idiot buried in the DW cavity I read 6 0r 8 volts at the sink.???

Pulled out the HUGE refer which was STUFFED into its space. There wasn't 1/16" on either side. I found where the handyman got the power for the DW/disp. He pulled from an original 2 prong recep behind the refer. He cut the ground off short and wrapped the terminals of the recep.

Wiring was BX so I had somewhat of a ground at that box. I redid the wiring and attached the gnd to the box. Voltage to sink went away.

I know the issue isn't resolved. I just gave it a better path to follow. I will be back next week to do the service relocate and will have to send someone up to replace some BX.

Until then, I don't think I can fully understand how the voltage was getting to the cast iron sink (PVC trap)

I guess my question is, how the heck did the voltage get thru the DW into the sink?

 

[LarryFine]

I guess my question is, how the heck did the voltage get thru the DW into the sink?

It's still possible that the sink is grounded, and it's your service ground that is hot. The voltage might have been line-to-neutral voltage imbalance.

The other connection might be the disposer housing, from the un-grounded EGC getting energized by the DW. But, the low voltage suggests a poor neutral.

 

[220/221]

It's still possible that the sink is grounded, and it's your service ground that is hot.

So all the bonded water pipes, gas pipes and ground rods are carrying current TO the sink? I suppose I could test this by reading from the bonded piping to a completely separate ground like..... a mud puddle??

The other connection might be the disposer housing, from the un-grounded EGC getting energized by the DW. But, the low voltage suggests a poor neutral.

My first thought was poor neutral but the refer, DW, disposal were all function properly.

I have thought this thing in a circle and have given myself a headache.

 

[Pierre C Belarge]

I experienced the same thing a number of years ago. After some investigation, I found out there was an energized wire touching the dishwasher frame, which was connected to the sink drain with a metallic drain from the dishwasher.

 

[Rewire]

For the apprentices reading this 22 volts will not kill you 120 will not kill you 220volts will not kill you 1480 will not kill you. Amperage WILL kill you at 10 milliamps you cant let go.

We did a simiular service call it turned out a wire saw shorting to the duct work which had a water line atached to a humidistate

 

[220/221]

So.....can 22 volts kill you if it were bolted to a pair of tight copper bracelets?

If not, what is the lowest voltage, given a proper connection, that could kill you ?

My next step will be to open up the jb on the disposal and look for a neutral to ground fault. The wiring will all be replaced next week but I still want to know where exactly it was coming from. The reality is that I will probably never know. I will refeed everything and call it done.

 

[480sparky]

So.....can 22 volts kill you if it were bolted to a pair of tight copper bracelets?........

It's not the voltage that kills you, it's the amperage. You can have a zillion volts flowing through your body, and if the amperage is low enough, you wouldn't even feel it.

But get the amperage up to 1 milliamp (no matter what the voltage is), then you start to feel it.

1 milliamp Just a faint tingle.
5 milliamps Slight shock felt. Disturbing, but not painful. Most people can "let go." However, strong involuntary movements can cause injuries.
6-25 milliamps (women) and 9-30 milliamps (men) Painful shock. Muscular control is lost. This is the range where "freezing currents" start. It may not be possible to "let go."
50-150 milliamps Extremely painful shock, respiratory arrest (breathing stops), severe muscle contractions. Flexor muscles may cause holding on; extensor muscles may cause intense pushing away. Death is possible.
1,000-4,300 milliamps (1-4.3 amps) Ventricular fibrillation (heart pumping action not rhythmic) occurs. Muscles contract; nerve damage occurs. Death is likely.
10,000 milliamps (10 amps) Cardiac arrest and severe burns occur. Death is probable.
15,000 milliamps (15 amps) Lowest overcurrent at which a typical fuse or circuit breaker opens a circuit!



The danger from electrical shock depends on...

• the amount of the shocking current through the body,
• the duration of the shocking current through the body, and
• the path of the shocking current through the body.

 

[Rewire]

So.....can 22 volts kill you if it were bolted to a pair of tight copper bracelets?

If not, what is the lowest voltage, given a proper connection, that could kill you ?

My next step will be to open up the jb on the disposal and look for a neutral to ground fault. The wiring will all be replaced next week but I still want to know where exactly it was coming from. The reality is that I will probably never know. I will refeed everything and call it done.

lets take 25 ohms (this is the minimum for a ground rod) and 22 volts,now using ohms law we divide the voltage by the resistance to find amperage.

22/25= .88 or 88 milliamps,death is possible

 

[480sparky]

lets take 25 ohms (this is the minimum for a ground rod) and 22 volts,now using ohms law we divide the voltage by the resistance to find amperage.

22/25= .88 or 88 milliamps,death is possible

.88 amps = 880 milliamps.

 

[ohm]

After seeing the mess in this house I would forget logical troubleshooting until I opened every outlet (lighting, receptacle, panel etc.) and inspected/redid same.

When there are multiple violations, such as this, logic is just a waste of time.

 

[LarryFine]

If not, what is the lowest voltage, given a proper connection, that could kill you ?

It depends on the impedance of the circuit: the body, the contact points, etc. Ohm's law applies to Mr. Ohm, too.

 

[dan filipi]

I once had a similar issue, customer getting zapped getting into the shower.
Turned out a piece of the chicken wire stuff the tile guys use was touching the hot at the vanity receptacle energizing the chicken wire which provided the path to the shower door frame.

Service work can be very interesting.

 

[hurk27]

I Run into stuff like this allot around here, it can be frustrating to find and very time consuming.

the main things that stand out in your photos, are the ITE panel.

These panels came with a little aluminum strap to bond the neutral bar, it looks like a fork on one end, and has a reduced stub on the other to go under one of the terminals on the neutral bar, then is bent to allow the fork end to aligned up to the hole next to the neutral bar, this hole is on the right in your photo.

So this means there is no no main jumper in this panel.

Next is all those small white conductors wrapped to form a neutral, this can lead to some of them not making connection and can cause a voltage drop in the neutral.

Now the voltage you have on the sink and the way it is varying to amount of load placed on the dishwasher plug would seem to me that you have a neutral return path through the water pipes for this plug.

It was common for DYS to grab a ground from a water pipe by running a small wire to the nearest pipe to a appliance, we have seen this many of time on the back of washers to stop a shocking washer, but the problem of that shocking washer was not that it was not grounded, but the fact the washer neutral somehow was inadvertently made connection to the EGC of the washer or washer circuit, this will allow any voltage drop of this neutral to be placed upon the grounding of this washer, or in your case dishwasher/sink, I would bet if you find the JB box all these circuits run to you will find a ground wire to a water pipe somewhere, and a neutral connected to the EGC of this circuit.

Either of these can be anywhere on these circuits.

Keep a simple circuit in your mind of how the current that feeds this circuit, and returns to the panel, using paths back that it shouldn't, it is the neutral return to the transformer that causes the most of these types of problems.

A case in point ( totally different situation) Where I had an apartment building, where we had residents receiving shocks from the water pipes when taking a shower, this was only on the first floor, where they had tile over concrete.

Lucky no one was hurt, as we measured 23-56 volts from a earth reference point, made by placing three ground rods in a triangle of 8 feet apart, out away from the building, this allowed me to do measurements at all points on the building grounding independent or the electrical system, which also led me to suspect the pad mounted transformer return path, which was the problem. the "C" clamp at the utility MGN where the concentric neutral connected was bad and had lost connection, the concentric neutral was bare and supplied the return path for a while until it failed leaving the grounding at the building as the return path for the transformer through the earth(7200 volts), then the city water supply pipe was getting holes in the pipe and was replaced with plastic, this allowed a sharp increase in voltage on everything bonded to this building. then we were called in to find it.

As it turn out the utility changed the concentric primary to this transformer pad, using a insulated concentric neutral this time, and new connection to the MGN and all was good.

So when you start getting voltage/current on things that are grounded, start looking at neutral paths and bonding of the EGC's.

As seen above it can even be caused from the utility side of the meter, even the primary's if the transformer lost its return path.

 

[hurk27]

:roll:Whoops I missed that the panel in the photo was a sub panel (very short memory) so it wouldn't have a MBJ, so please disregard my goof

If only I could retain the things I could when I was younger LOL

 

[greenjeans]

I always ask if any work was proformed in the house recestly. electrical, plumbing , and any handy man work by owner or others. Alot of times i hear my answer yes, in this case a owner in a 90 year old home replaced a bath fixture with a new strip fixture, and didnt know where the green wire got tied into to. Soooo he tied it to the blacks wire stuffed in the back of the box( his thinking, three wires-three connections). needles to say, wife was getting shooked every time she leaned on her stainlees steel counters to turn on the though wall exhact fan, with the pull chain. read 120v from counter to fan housing. this was a k+t house, and grounded all the metal boxs with a# 14 wire to plumbing. i like to ask alot of qutions, saves me time (troubleshooting) and customers $$$$...................just my two cents worth!!

 

[iaov]

Always my first question when troubleshooting, Has anyone worked on this recently. Both in resi and industrial . If they have ,90% of the time that is where you'll find the problem.

 

[davet]

Voltage at Kitchen Sink: Restaurant owner called me to say that his people were getting shocked on various appliances,sinks etc.Checked voltage at various points to ground.
Nothing.Checked panel,main ground,neutral,nothing.No voltage present.Next day,called back again.Went through same checks, 120 volts to ground. This day,it was raining.Went outside to look at main feeders coming to building.All connections were bare.I surmised that the rain was conducting from hot to neutral.Called power company to explain situation.They drilled me like a high school kid.I finally convinced them to come out and change the feeders from pole and insulate their connections. Since repairs were made next day, no further shocks were reported.No charge to customer from power co.Weather played a major influence.Be aware of your surroundings,both inside and outside.

 

[hotblueelectric]

1.5-18 volts at outdoor spigot

1.5-18 volts at outdoor spigot

Went on a service call today where customer was complaining of some tingling he felt at his back yard faucet. Attached one end of my fluke to the faucet and the other lead went into the moist soil. Read 1.5 volts. Turned off all breakers voltage still there. Turned off main voltage gone. Turned on microwave in the kitchen voltage goes to 10.o volts, turned another microwave they have in the bedroom (different circuit) voltage goes to 18.0. Turned off microwaves volts back to 1.5. Plug in the vaccum at any other outlet in the house and the volts goes up to around 6.0. Checked all connections at the main panel, hots, neutrals, and grounds. A few neutrals were a little loose, also a few loose hots and grounds. Checked cold water ground at the water heater and tightened it up. Checked connections at the meter base and all connections tight. Customer said that a new water meter was installed but it is all brass. Left for the day. I asked customer to check the attic and make sure the cold water ground is complete from panel to water heater and not broken. I also asked hin to call his POCO and have them check their end. This house was built in the 80,s. The only thing is there is no ground rod or ecg. Should'nt this voltage dissapate through the cold water ground to the neutral. Main panel neutral bar is correctly bonded to the case. Any ideas. Thanks for any ideas.

 

[al hildenbrand]

Hotblueelectric took his question above and started a new thread with it here.

 

[IMM_Doctor]

Went on a service call today where customer was complaining of some tingling he felt at his back yard faucet. Attached one end of my fluke to the faucet and the other lead went into the moist soil. Read 1.5 volts. Turned off all breakers voltage still there. Turned off main voltage gone. Turned on microwave in the kitchen voltage goes to 10.o volts, turned another microwave they have in the bedroom (different circuit) voltage goes to 18.0. Turned off microwaves volts back to 1.5. Plug in the vaccum at any other outlet in the house and the volts goes up to around 6.0. Checked all connections at the main panel, hots, neutrals, and grounds. A few neutrals were a little loose, also a few loose hots and grounds. Checked cold water ground at the water heater and tightened it up. Checked connections at the meter base and all connections tight. Customer said that a new water meter was installed but it is all brass. Left for the day. I asked customer to check the attic and make sure the cold water ground is complete from panel to water heater and not broken. I also asked hin to call his POCO and have them check their end. This house was built in the 80,s. The only thing is there is no ground rod or ecg. Should'nt this voltage dissapate through the cold water ground to the neutral. Main panel neutral bar is correctly bonded to the case. Any ideas. Thanks for any ideas.

Microwave in the BEDROOM? ..?