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4K views 43 replies 15 participants last post by  220/221 
#1 ·
Hi guys, I received a call today on a dryer not working. I go out and measure voltage from panel to recep. And machine, all read 240 and 120 to its respective points. It was a 3 wire hook up. After sometime, I get an idea and removed the ground cable and placed on the neutral bar. Dryer starts right up and works as intended. I know bare ground cant be on neutral bar, however not sure why machine didnt work other wise. Any ideas ?...thanks again.
 
#10 ·
Is the circuit fed from the main panel or a sub panel? If main panel, the ground and neutral ARE the same point. It shouldn't matter where it is landed. If you actually were reading 120 and 240 where you should at the machine, power was not the problem anyway. Probably a thermal overload on the appliance cooled off, or it reset when you turned power off and on again. Power was probably fine the entire time.
 
#24 ·
Tell the customer it's the only way. Cut the walls or have EMT installed haha

You could also explain why three wire appliance installations are potentially dangerous.

Or... Drop the job. No point in doing a job where the customer isn't going to allow you to safely fix the situation. It's your name, license, insurance, etc on the line -- not theirs.
 
#27 ·
The larger underlying problem here is they have been using the Equipment Grounding conductor as a neutral for the operation of this dryer.

For some reason, the equipment grounding connection has gone bad (probably the main bonding jumper or screw at the service panel), making it unsuitable as a current-carrying connection.

When you shifted that ground wire to the neutral, you were able to re-establish a good circuit connection, thus bringing the appliance back to life. :blink:

So, while it's prudent to replace the cable with a proper 4-wire configuration, you still have the problem of a bad grounding connection to deal with.

Betcha it's charred or burned out at the main panel, since it's been used for current-carrying purposes over the long haul ...

:whistling2:
 
#28 · (Edited)
This is confusing to me.

First, remember that the dryer motor is 120V


You removed the dryer's bare ground/neutral from the neutral bus and put it on the ground bus at the sub panel and it started working?

Doesn't that tell to that there is no neutral at the sub panel?

If the neutral to the sub has failed, any 120V loads wouldn't be working.


The bare ground to the dryer is the least of your problems. Bare grounds on dryers are approved in older retrofit SE installations. I'm not saying it's a good idea, in fact it was never a good idea.....but that's not your #1 issue.

If the neutral to the sub is open, the current from the dryer (motor) will be flowing on the ground path which goes all over the place and could lead to an electrocution hazard while it is running.

If this is the case, I'd call them and tell them not to use it until you get back there.
 
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