Electrical Shock While Working On Dryer ?

YES! I would run a wire from the dreyer case to ground on any 3 prong

I have done that to mine...

Mark

Interesting question. You prompted me to do a little test and in my test WD-40 did not conduct a current, but it did clean off contacts so that they made a better, lower resistance connection. It made a big difference on the contacts was was checking.

In any case I suggest that everyone make it a habit to unplug any appliance that they are going to open up.

I am not sure of the rule, but I believe that some if not all current three wires plugs for 240 are two legs and a ground. An appliance may not need 120 or it may use a transformer. You may be able to tell by taking a good look at where that third conductor goes and if it is connected to the case.

???? How would that happen with just the an open circuit and no other failure?

Next time unplug.

The casing needs to be grounded. I went back and checked mine. It is grounded.

Great idea.

Dick

Depends on what you mean by open circuit. I wouldn't assume that a dryer that's turned off is consuming _no_ power. It could have electronics that are always on.

As for full voltage on the case, consider: in a three wire dryer/stove connection, the two hots are connected to the elements (thru switching) to provide 240V.

The 120V motor/clock/timer etc. are connected to one hot _and_ the third wire, and the case is connected to the third wire too.

If you cut the third wire between the dryer and the panel, the case becomes live if there's anything switched on on the 120V side.

If the dryer is operating at that point, what happens is that the heaters stays on, yet the timer and motor stop.

Eg: if the motor is switched on, one side is connected to a hot, the other side is connected to a _floating_ (not grounded) case. If you're grounded (eg: touching a pipe, or a grounded clothes washer) and touch bare metal on the case, you get zapped - _thru_ the component that's trying to conduct power (eg: the motor).

I would think most likely that the OP has a neutral/grounding problem.

It's best to kill power to appliances before opening it, even if you think it's totally off and figure you can stay away from the hot side of the switch.

When I had to replace the heating element in our dryer a few days ago, I killed the breaker. I didn't know for sure whether the element switching killed _both_ hots or just one, and I didn't want to find out the hard way. I tested it anyway to make sure I got the right breaker.

Many 220V appliances have the case "bonded" to the neutral. If the neutral opens, voltage can appear on the cabinet. I doubt it would be

Newer homes are wired with 4 wire 220V outlets to prevent this, that way both the neutral and ground wires have to open before this could occur.

I would not count on a cold water pipe as a ground.

It sounds like the dryer is grounded properly. And when spraying, the can touched a live wire or the spray sprayed into a live wire and the electrical path went from the can through your hand/arm and then through your other arm/hand to the frame of the dryer.

Were both arms tingling?

Also a better test to see if the spray conducts electricity is to use 240 volts for the test. I know some ohm meters are not capable of testing some electronic components because the voltage in them is not high enough. Perhaps this spray will conduct electricity if the voltage is high enough? Warning! This would be a very dangerous test, so don't try this at home.

Also one time a distributor on a car was wet inside (water) and car would not run. Spraying wd-40 on the inside contacts made the car run again.

According to JK :

It essentially _can't_ be 240V. The only way you can get hit with a 240V shock is if you touch both legs of the main simultaneously. The highest voltage (normally! ;-) available in a house is 120V relative to ground.

Well, if you actually got a shock, then yes, it was voltage between the neutral and the ground. Your neutral and ground are the same, and the frame is attached to it. So if the neutral is floating, then there could be voltage between the frame and ground. However, the dryer wouldn't work in that condition; there would be no 120v circuit for the control; so it is unlikely. I think you misunderstood what happened; either you didn't get a shock, or you got it off a hot.

That would be a code violation. If your neutral is sound, the separate ground isn't needed. If your neutral is floating, you have created a dangerous ground loop. So don't do it. (I suppose it would be relatively safe to unbond the ground and then ground the frame, but it is neither necessary nor legal)

The matter certainly requires more investigation, but a water pipe is not the solution.

yes, by full voltage I meant 120 V (not 240)V...

Mark

you have an excessive amount of faith in the rules.

if everything is wired per code for a 3 prong 220 V outlet..., and then there should happen to be an OPEN circuit failure in the neutral circuit anywhere in the system leading to the dryer or in the dryer itself, the dryer case will become energized with 120 V through the 120 V clock circuit in the dryer.

The day I realized this, I lost my faith in the "code" and I added an external ground wire to ground the case of the dryer to the washer right next to it which has a 3 prong 120 V plug.

So your saying if my dryer case happens to touch the washer case right next to it .....that is a code violation?

too bad

Mark

Mark

Yes, that is what I said. But I also said that the dryer wouldn't be working because the 120v clock circuit would be open (except perhaps through you.) If your dryer isn't working, unplug it before working on it. There, your problem solved.

No, of course not; the circuit between the machines has many times the resistance of the neutral, so it effectively doesn't exist.

Yeah, it is too bad. You think they write the code for fun, or to employ more electricians? It is your house; if you want to ignore code I wish you the best of luck.

Just fixed a good friends electric dryer. installed new element

Its a 3 wire plug 240 volts.

She has a 2 year old. The dryer is old.

Would it be a good idea to add a ground wire from the case to a good house ground just to be on the safe side?

the area the dryer is in has a water problem. that makes me more concerned. the washer and dryer sit on a pedastal, like a skid made of outdoor wood. very well built, makes working on appliances hard. floor is frequently wet.

There is no neutral in a 220 connection. Two hots, no neutral, and a ground if it is a new enough install.

Yes, I know the really new stuff has a four wire connection that has 2 hots, ground, and now a neutral in case the modern appliance needs 110 volts.

I would check the ground circuit and the case ground with regard to getting shocked. Electricity should not go to the case unless something is wrong. ______________________________ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

no I don't want to ignore code, almost always the code makes sense....

in this particular case it doesn't. In fact they no longer allow 3 prong 220V outlets in new construction for this very reason....

I want to use my brain and I want my house to be safe, and if that means I need to run a ground wire between the dryer and washer, so be it.

Mark

Dick Adams posted for all of us... I don't top post - see either inline or at bottom.

So all his plumbing is now electrically live? Yeah great idea - NOT

Bill posted for all of us... I don't top post - see either inline or at bottom.

So Bub where is he supposed to run this test? Supermarket? Police Station? Underwriters Labs?

Your whole post was a waste of time and dangerous - get off the Internet!

Then switch off the breaker or pull the fuse.