Shocked from electric dryer

[tpolley]

My electric dryer has started giving a little shock when I touch it. I checked the power cord going into the back of the machine. Nothing obvious is wrong. I'll have to open it up and look for any damaged wiring.

If there's voltage on the frame of the dryer, I should be able to measure it, right? How would I measure it to verify that I fixed the problem instead of just touching it to see if it's still faulty

It's a three wire circuit. Two hot wires and a neutral. I know I should probably upgrade to a 4 wire with ground and that would help protect the user in this situation, but it won't really fix the problem I currently (pun intended) have.

 

[wyliesdiesels]

3-wire dryer setups have the frame bonded to the neutral.

So if youre getting shocked then you most likely have a bad neutral connection.

You wouldnt be able to meter it if its neutral current which is the most likely case.

 

[sberry]

Make sure the bond strap is installed. These are wired wrong all the time. Appliance sales and installers are very poorly trained and it seems company owners throw these guys out in the wind. I am surprised they are not sued on a regular basis.

 

[The Cobbler]

it's not a static shock ?

 

[Milton Shaw]

The dryer is 120 and 240 volt. The 240 volt works the heaters and the 120 volt runs the motor, light and the timer. The body of the dryer should be grounded with a bonding strip to the white neutral wire and the two hots to the red and black wires on a three wire install.. Check the cord and if correct then check the outlet. As a repairman I once saw a dryer welded to the washer. Chassis of dryer was wired to 30 amp hot line and vibrated rubbed thru the paint and welded itself to the washer until the ground wire on the washer burnt off. Very dangerous I didn't see how some body had not gotten shocked.

 

[walta]

When you touch the dryer and get shocked we tend to think the fault must be in the dryer but that is not necessarily true.

The dryer is likely to be well grounded and safe.

More likely you were touching some other appliance with a fault you got shocked only once you came in contact with a ground by touching the grounded dryer and the faulty appliance at the same time did you complete the circuit and get shocked.


Walta

 

[wyliesdiesels]

When you touch the dryer and get shocked we tend to think the fault must be in the dryer but that is not necessarily true.

The dryer is likely to be well grounded and safe.

More likely you were touching some other appliance with a fault you got shocked only once you came in contact with a ground by touching the grounded dryer and the faulty appliance at the same time did you complete the circuit and get shocked.


Walta

That is definitely a possibility as well. And ive seen that before. Washer frame was energized. Customer leaning against washer then touched dryer and got shocked.

 

[justsam]

Use a voltmeter set to measure AC voltage. Connect one probe to a known ground, such as cold water pipe if metallic, extend this lead if necessary to get a known good ground. Use the other probe to touch cabinet of suspected energized device. You should see near zero volts.

Make sure the device under test is turned on and operating, as a poor connection may not show itself except under load.

 

[wyliesdiesels]

Use a voltmeter set to measure AC voltage. Connect one probe to a known ground, such as cold water pipe if metallic, extend this lead if necessary to get a known good ground. Use the other probe to touch cabinet of suspected energized device. You should see near zero volts.

Make sure the device under test is turned on and operating, as a poor connection may not show itself except under load.

If the OP is being shocked by neutral current, then the above test will not show anything in regards to that because neutral and ground are bonded in the main service panel.

 

[rlitman]

If the OP is being shocked by neutral current, then the above test will not show anything in regards to that because neutral and ground are bonded in the main service panel.

Not necessarily. Resistance across the neutral will leave a voltage differential over it when current is flowing. The voltage shouldn't be that high, but could be if the resistance is high, such as with a bad connection on it somewhere.

And the OP says "little shock". It's pretty easy to feel the tingle of 60hz, even if the voltage isn't dangerously high.

 

[justsam]

The OP has stated that this condition has just started, so I am excuding the notion that wiring was done incorrectly. I do realize that ground and neutral are tied together at the panel, but I am guessing a high resistance path somewhere in the neutral to the dryer has developed, or the dryer is not the culprit at all, but it is providing a ground reference for some other faulty device.

OP, what are the conditions under which you get this "tingle"? are you touching anything else? What is the floor material? Are you touching a water faucet when this occurs?

Bottom line if there is enough voltage to give you a "tingle", there is enough voltage for any modern high impedance voltmeter to read. You just need to determine the measuring points.

 

[sberry]

Or missing bond strap and the chassis is floating. There is an assumption that it was wired right from the start, if the N was interrupted it probably wouldn't run.

 

[alfredeneuman]

Or missing bond strap and the chassis is floating.

This is very likely. There's bound to some lint buildup in the case over time, and when damp, it's conductive. That would explain why this problem just showed up.