Unplugging dryer caused burned up equipment

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kwired

Electron manager
Location
NE Nebraska
I had a service call yesterday here is what was presented to me when I showed up.

Homeowner was painting laundry room pulled dryer out and sometime while unplugging it (the receptacle was pretty looslely mounted) heard popping noises in another room. In the other room was a multioutlet surge protector plugged into a receptacle with TV DVD satellite receiver plugged into it and there was black soot on the wall above the outlet and surge protector and a horrible burning smell. They also heard popping sounds in another room with a power strip type surge protector and computer equipment plugged into it. They immediately turned off the main breaker in the panel and eventually called me to see what was going on.

This was a mobile or manufactured home around 30 years old, Service was not properly installed but did have 4 wire feed to the panel and no bond screw installed in panel, Dryer receptacle was a 4 wire receptacle with 4 wires installed, the only issue with the receptacle was that it was loosley mounted.

I did not have all my service tools with me when I initially showed up because I unloaded the truck to do something else yesterday and did not intend to use them, stopped by because the customer was on my way home to take a look. I was able to open the panel and saw nothing obvious and open the dryer receptacle and nothing obvoius there either.

When I went home to get more tools I was thinking how could unplugging the dryer possibly cause these two surge arrestors to start smoking, and what else in the house may be effected. Before eventually returning I had a pretty good scenario in my mind and eventually found out it was mostly correct.

I want to pick some of your brains to see what you find for possible causes. I have given you all the information that I had that time before actually having a meter to check what was going on.

This is just for fun, education, whatever.

First person to solve the problem gets a dozen smilies:)
 

480sparky

Senior Member
Location
Iowegia
Service neutral was open, and the dryer was bonded internally. When it was unplugged, there was no path for the neutral current, so the voltages started to go all whacky.
 

kwired

Electron manager
Location
NE Nebraska
Service neutral was open, and the dryer was bonded internally. When it was unplugged, there was no path for the neutral current, so the voltages started to go all whacky.

:):):):):):):):)

Sorry the forum only allows 8 images in a message I still owe you 4 smilies. What you do with your smileys is up to you.

I didn't expect the first response to be the winner.

There was a bad neutral ahead of the panel and the internal bond was installed in the dryer and carrying the neutral for the whole house.

Luckily their TV and computer equipment still worked (when I left anyway).
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
:m


Sorry the forum only allows 8 images in a message I still owe you 4 smilies. What you do with your smileys is up to you.

I didn't expect the first response to be the winner.

There was a bad neutral ahead of the panel and the internal bond was installed in the dryer and carrying the neutral for the whole house.

Luckily their TV and computer equipment still worked (when I left anyway).

I'll donate the others :):):):)

From Droid so hope they show.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
Dang i got here too late. Was what first hit be was dryer had ground and neutral bonded and was using it to complete the neutral thru the ground. They actually were very lucky that it got caught before the trailer burned down.
 

jetlag

Senior Member
:):):):):):):):)

Sorry the forum only allows 8 images in a message I still owe you 4 smilies. What you do with your smileys is up to you.

I didn't expect the first response to be the winner.

There was a bad neutral ahead of the panel and the internal bond was installed in the dryer and carrying the neutral for the whole house.

Luckily their TV and computer equipment still worked (when I left anyway).

question , why did they bond the neutral in the dryer if it had 4 wire, if that wasnt done they would have known when they lost the service neutral
 

kwired

Electron manager
Location
NE Nebraska
question , why did they bond the neutral in the dryer if it had 4 wire, if that wasnt done they would have known when they lost the service neutral

Homeowners told me place that sold them the dryer put the cord on it.

Many appliance stores/installers have no clue what or why there is a difference between a three and four wire install except there is a different number of wires in the cord.
 

kbsparky

Senior Member
Location
Delmarva, USA
....Luckily their TV and computer equipment still worked (when I left anyway).

IF you check the power supply requirements on those items, I'd be willing to be that they are the newer type, which can take 100-240 Volts. Losing the neutral and any resulting spikes in voltage would have no effect on those whatsoever.
 
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