burning plastic smell turns out to be hotwater heater 120 vac wirenut

[Miltp920]

This could happen on any brand. When we smelled the burning plastic, it was strongest under the sink. I felt the plastic box covering the heating element wires and it was thermally hot. I had already killed the power at the breaker. The pics show what I found. I believe this was a loose wire nut connection that took 2 years to show itself. When i tried to loosen the white wire nut, it was very loose, i expected to feel some resistance when turning it off, there was none. Also when I disconnected the white wire to the heating element, the black one fell out of the connector still on the heating element screw. See last pic. that may have been loose from factory. Maybe that loose connection caused heating on the black wire back at the wire nut. The one black wire melted to the back of the plastic box. It does have exposed wire, It almost looks shaved, but I did pull it away from the black plastic box, and it could have exposed the wire then. All I know is this should NOT happen. IF you smell something like burning plastic under your sink, kill the power to the hot water heater and investigate. SCAREY

 

[rxbristol]

Re: burning plastic smell turns out to be hotwater heater 120vac wirenut

Great investigative find. Thanks for posting.

 

[donr827]

Re: burning plastic smell turns out to be hotwater heater 120vac wirenut

I had the same problem several years ago. When I replace a wire nut I always wrap the nut and cord with electrical test to hold the two together.
Don

 

[mslater]

Re: burning plastic smell turns out to be hotwater heater 120vac wirenut

I had the same problem several years ago. When I replace a wire nut I always wrap the nut and cord with electrical test to hold the two together.
Don

holding the insulated part of the wires together won't do much for the arcing if the wire nut isn't installed properly

 

[wdk450]

Re: burning plastic smell turns out to be hotwater heater 120vac wirenut

Over the years the AC electrical connections to the water heaters has been a source of problems. In my case, the stripped wires were evidently too close together beyond the wirenuts and I had intermittent tripping of the AC breaker to the water heater, until I crawled into the storage compartment utilities access to get at the back side of the water heater and the water heater electrical connections box. Re-doing the wirenut connections there solved my problem, too.

 

[donr827]

Re: burning plastic smell turns out to be hotwater heater 120vac wirenut

holding the insulated part of the wires together won't do much for the arcing if the wire nut isn't installed properly

True, but his trailer is a 2014, at least a year old, presumed the connection was good at time of delivery. Mine was almost two years old when it happened. Pulling down the bumpy roads loosens everything including my filings.
Don

 

[Miltp920]

we bought our 2014 in August of 2013, so it has been 2 years. bumpy roads must have loosened up what I presume may not have been all that tight from factory. Black wire lead to HWH only had 1/4 inch of insulation stripped. So most likely had 1/8 inch originally clamped in terminal clamp-as it fell off when i touched it. not even a tug.

 

[mslater]

the first thing i did with my 2014 B.H. was torque all the panel terminations and check the wires were stripped properly …. (found 6-8 wires that weren't tight ) that would have eventually become a problem…. cord should be checked too …most of the joints i have checked have wire nuts that aren't tight or the ends aren't stripped the right length , than they loosely wrap electrical tape around the joint .these trailers don't have near the vibration as many industrial buildings or machinery that employ the same wiring methods without as many failures. i don't think the installers have been trained properly in how to do it and the factory doesn't care