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shocking range

4K views 36 replies 15 participants last post by  mpoulton 
#1 · (Edited)
My daughter was just telling me her husband was washing dishes or something, and for whatever reason he touched the electric range/stove. He got a good jolt that tinkled for some time!

Besides being a badly designed old kitchen in an old house, what do I need to look for? Grounding? This is the ole 2 wire with grnd 3 prong plug.

The power is coming from a breaker box.

He did have water running over his hand when he touched the stove.

Yeah, I know, bright idea.
 
#3 ·
hi

yes you do have a grounding problem ! this mean your wirering must be 35 plus years old this would requier a electricien to change most wire in your house or at leas the 1 closse to water source ( kitchen bathroom ) you might want to test your house ground to !

how old is your house and wirering ?
 
#13 ·
Not true, not relevant, and not helpful. Don't give advice if you're not up to speed.

You have a bonding problem, not grounding. The problem may be (likely is) a loose neutral connection somewhere in the range circuit. The metal chassis of the range is electrified because the clock/timer/lights use the neutral connection as their return, and the chassis is bonded to the neutral. Tighten the connection of the neutral wire in the panel and in the receptacle, and make sure the plug is making good contact in the receptacle.

This problem of the appliance becoming electrified in the event of a loose neutral connection is the reason why 3-wire feeds are no longer allowed for 120/240V appliances.
 
#12 ·
I did tell her things like this is why the code calls for the 4 wire rec's now in new work.

I have changed a few pigtails for this reason when I sold a stove and someone had the newer wiring in their house. That was a few years ago.

I still have 1 or 2 in my shop on the wall.
 
#5 ·
You have to be aware that this is not 'ol 2 wire with ground' This is two hots and a neutral wire. The stove has either 120v or 240v touching the case somewhere. Most likely 240v if he felt it good.

Replace the appliance or repair the wiring. The stove should not be used under any circumstances until it is repaired or replaced. A path for fault current(ground) should be added to avoid any shock hazards in the future.
 
#7 ·
Does the rest of the house work ok? Lights get bright or dim when other lights, TVs, hair dryers are turned on?

If the rest of the house is ok, and the stove is 3 wire, then almost certainly, the neutral/ground wire is loose or broken somewhere between the stove and the panel.

Even though the stove is 240, the most shock you can get is 120. This is because in order to get shocked by 240, you have to be touching one of the hot legs, then touch the other. About the only other way you can get blasted with 240 is if the neutral is open somewhere from the service to the utility transformer. If the loads are such that one of the hot legs is effectively grounded and you grab the other hot......240.

Rob
 
#10 ·
I will definitely check te neutral tomorrow. Last April a storm tore the meter and weather head off. I replaced it and the panel. I had to extend one circuit. I am thinking it was the stove circuit. And yes, it was inspected.

I wish, and I may yet, I had went ahead and changed the stove circuit to a 4 wire so I could seperate the neutral from the case.

As far as not getting 220 volts, what if an element is touching the stove? Even the surface eyes pull 220 if on high, right?
 
#15 · (Edited)
You have a combination of two problems:

1. Due to manufacturing defect or wear from vibration or an earlier imperfect repair, a live wire inside has somehow come in contact with the metal framework of the stove,

2. The stove is not adequately grounded (bonded to ground).

Were the stove properly grounded, current from a fault (unwanted interconnection letting unwanted current flow) to the metal frame would "drain" back to the panel neutral, possibly tripping the breaker if the fault current were large enough, rather than endanger some person touching the stove. While the smallest common branch circuit breaker is 15 amps, it might take less than one tenth of an ampere to electrocute someone.

Numerous treatises have appeared on this web site about the necessary components (equipment grounding conductors, grounding electrode conductors, etc.) to adequately ground things.

It is not easy to find the exact location if problem #1 existed.

Among the places where loose connections can occur are all the screws and set screws in the breaker panel. Take a moment to tighten these up. Someone with lots of electrical experience should do the big set screws on the big lugs where the fat wires from the meter come in.

You can run a bare or green covered #10 copper wire from the stove framework down to the breaker panel ground terminal strip (bus bar), exactly, approximately, or vaguely following the route of the stove branch circuit cable, if the latter does not have a ground wire (EGC).
 
#19 · (Edited)
I was thinking I was told once to ground a washing machine to a water line.

That maybe the reason I have heard of some plumbers being killed by coming into contact with energized pipes?

I get what is meant by the pipe connection to the earth being broken sometimes. I mean like maybe a pvc dresser coupling used in a repair.
 
#18 · (Edited)
He did have water running over his hand when he touched the stove.

Yeah, I know, bright idea.
I'd go easy on the SIL. Electrical safety shouldn't depend on some set of complex rules like don't touch this while using that or avoid this while doing that. It should be safe no matter the combination and order of things happening.

The problem here is the range chassis is not at ground potential. It has become elevated, probably by a neutral problem in a 3 wire circuit. I guess there is an off chance the plumbing is electrified and the range is bonded but that seems much more of a long shot (note 1). If you have a digital volt meter measure from stove chassis to metal water pipe. Then try turning on this and that (particularly things that are likely 125VAC like lights or controls) with the stove to see if that voltage bounces around.

Should be easy enough to fix. Find where the neutral has become compromised in the feeder circuit. Either at panel or range most likely. Hopefully there are no junction points between these two.


Note 1 Sometime house plumbing is floating electrically for one or both of these reasons. a) A water softener was installed and the bonding of the electrical wasn't continued across a plastic water softener manifold b) The water heater has dielectric couplings to protect the (steel) tank from galvanic corrosion. The copper side should be bonded together (Hot and cold).
 
#20 ·
I'd go easy on the SIL. Electrical safety shouldn't depend on some set of complex rules like don't touch this while using that or avoid this while doing that. It should be safe no matter the combination and order of things happening.

The problem here is the range chassis is not at ground potential. It has become elevated, probably by a neutral problem in a 3 wire circuit. I guess there is an off chance the plumbing is electrified and the range is bonded but that seems much more of a long shot (note 1). If you have a digital volt meter measure from stove chassis to metal water pipe. Then try turning on this and that (particularly things that are likely 125VAC like lights or controls) with the stove to see if that voltage bounces around.

Should be easy enough to fix. Find where the neutral has become compromised in the feeder circuit. Either at panel or range most likely. Hopefully there are no junction points between these two.


Note 1 Sometime house plumbing is floating electrically for one or both of these reasons. a) A water softener was installed and the bonding of the electrical wasn't continued across a plastic water softener manifold b) The water heater has dielectric couplings to protect the (steel) tank from galvanic corrosion. The copper side should be bonded together (Hot and cold).
I get what you are saying. I just never thought it was completely safe to have part of your body in water and toucing some electrical appliance, whether it is on or off. :laughing:
 
#24 · (Edited)
The path through the human body has some resistance, mostly at the skin if that is dry on the outside. At all times in any portion of an electrical circuit, volts measured between the start and end of that portion equals amperes times resistance of that portion, or amperes equals volts divided by resistance. If the voltage is not high enough for a fatal current flow to occur, the person isn't electrocuted yet.

In the case of a person experiencing electric shock, usually once a good amount of current (say 25 milliamperes) gets flowing, the characteristics of the precise path through the body and especially at the skin where the current enters and exits changes as a result of heating so as to lower the resistance. In turn the current increases.

The current causes burning of body tissue and parts as it passes through. When the current, from where it enters the body to where it exits, passes near or through the heart, the heartbeat becomes irregular or may stop completely.
 
#33 ·
Anyway, good call on a loose neutral it seems.

When I first got there I just ran my pximity tester over it. It started beeping. Knew something was wrong. These things can give you pretty good hint if something is live. No, Idon't really trust them with my life, but if they sound off, I feel pretty certain something is live. If it does not sound off, I most likely will check with a multimeter or another volt meter with prongs.

The rec it self was old and the neutral clamp/receiver seemed a little lose to me. It was also covered with crud when I removed the cover as it was upside down on the wall and the cover was busted on one side. I had been meaning to get up there and change the cover. In the meantime, someone :)whistling2:) had wrapped duct tape around it for a temp fix.

This was also the circuit I had to extend when the storm pulled the meter off outside and when I changed the old panel for a newer one with more space in it. I had to install a 4" makeup box a little less than a foot above the newer panel and splice wires using split bolt clamps with the nut the screws down to clamp the wires. On the grnd splice, I had 1 stranded and 2 solids with one attached to the metal box. This splice was lose.

Lying here thinking about it, I think I need to go back in a day or two and see why I have a solid in the box as a ground.

I'm so screwy right now, I may have extended a second circuit with the smaller wire.

Like I said, it was inspected by the city inspector. The same one that came by as I was starting to replace the meter. :whistling2:

Anyway, I'll be back up there to put a screw in the cover of the power block on the stove and will double check things.

I told my daughter I thought I had it fixed, buit to tell her hubby thathe might want to turn it on and off with his hand turned backward in case it got him again. Told her if he turned it on like he normally did, it might make him grip it and he would not be able to turn lose. With his hand backward, he would not grip it and would have a better chance of getting lose.

Heheh, her response? "Are you kiddingme? Is this like forever?" :laughing:


Thanks for the info, I am sure it saved me some time.
 
#35 ·
On the grnd splice, I had 1 stranded and 2 solids with one attached to the metal box. This splice was lose.

Lying here thinking about it, I think I need to go back in a day or two and see why I have a solid in the box as a ground.
Ummm... if this is an old 3-wire circuit, it doesn't have a grounding conductor. The frame of the range is bonded to the neutral, but you can't use the neutral to bond other stuff on the circuit. It's not a ground. It needs to be insulated all the way back to the panel's neutral bar. Otherwise you risk electrifying even more metal.
 
#34 ·
Actually, I need to see how this thing is grounded to the case. I was expecting to see a ground strap on the neutral connection. It has been a long time, but I doubt this one ever had a strap like I am thinking of.

I might make a different post on that subject.
 
#36 ·
Tis is the old 3 wire with 2 insulated wires and one bare stranded wire wrapped arond them. I have seen this kind of wire on many ranges/stoves, I think, and the bare stranded was always used as a neutral all the way back to the panel.

I will say it makes me nervous to think of this bare wire being against something metal if something does go wrong. When I put the cover back on the 4" makeup box, I am pretty sure the neutral was touchinhg the cover.

I am about to talk myself into getting about 20' of new wire and go 4 all the way,

I wll go back and take another look at things. I'm thinking the inspector should have caught something if it was wrong. Then again, from what I hear, these guys are not always the sharpest tool in the box.
 
#37 ·
I am about to talk myself into getting about 20' of new wire and go 4 all the way
That's a darn good idea.

I wll go back and take another look at things. I'm thinking the inspector should have caught something if it was wrong. Then again, from what I hear, these guys are not always the sharpest tool in the box.
Inspectors definitely do not catch every problem. They can often miss serious problems.
 
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