Burned up power cord -- what is the cause? What damage could there be?

[TravelTiger]

Hi all,

We recently began full-timing in the ElkRidge in a new RV Park. This area of the park has new power, water and sewer hookups, installed within the last year.

We've been here about 2.5 weeks. Yesterday, while I was working on my computer and Tony was just sitting in his chair, we heard what sounded like a rock hitting the glass window, a few times in sucession. We both jumped, and said "what was that!" Then the power went out, and smoke came out of the TV (which was not on at the time.)

We immediately threw the 50amp breaker inside, and outside at the pole.

We have a SurgeGuard 50amp external protector.

We discovered that the RV's 50 amp power cord male plug had melted to the female SurgeGuard plug.



Upon more investigation yesterday and today:

1. no evidence of charing at the Marinco plug or wires to it at the back of the trailer.
2. no evidence of melting/charing at the Park Pedestal.
3. Park managers said electrician checked the Pedestal, and was OK but we did not see this (we were out getting a new power cord and SurgeGuard).
4. no evidence of burned/loose wiring at the breaker box.
5. noticeable burned wiring smell in the surge protectors plugged into a few outlets around the RV -- behind TV, back wall, bedroom (I assume they sacrificed themselves during a surge?)
6. With new power cord and new SurgeGard (all we could find near us) park power reads OK, no reverse, open, etc. New Furion power cord has lights that indicate power on both legs.
7. Checked with a Kill-o-watt, all wall and GFI outlets read approx. 120v.
8. Converter charges battery.
9. Water heater heats water.
10. Microwave warms.
11. Ceiling fan/light works.
12. one GFI plug in kitchen was tripped.
13. Both ACs turned on (separately) and cooled.
14. Fridge seems to be working OK, but since it only has a "auto" light for running on propane or AC, I cannot say for sure that AC is working.
15. The SurgeGuard "rattles" now which indicates to me it's fried.

Other observations:
- It's been 102+ here the past week, and I know we've got a lot of fans and other electrical needs plugged in.
- We got a new neighbor about a week ago, a 34ft travel trailer. These two rigs are the only ones on this branch of the park.
- This connection between power cord and protector had a plastic locking device on it, so it is very rarely disconnected. I admit we have not really looked at it recently.
- We discovered upon testing our breakers and what's on them that the plugs for the two slides, the back wall, and the MICROWAVE are on the same 15amp breaker which was not the 20 amp breaker labeled "Mic"

We have not tested any devices that were plugged into regular outlets yet to see what my have been lost.

We are not electrically inclined, so we need some sound and specific advice.

We have opted to not stay in the unit until we get this figured out.

We're not really in a position to take it to a dealer, as we are both living and working out of the coach. (staying in a motel at the moment.)



Prayers for our sanity would be helpful as well, as this is a stressful time.

 

[jnbhobe]

From what I see you had a loose connection at the Surge-Guard receptical. Since you were using a lot of power with a loose connection it got hot and melted. I would say the lug on the bottom was the loose one. I don't like surge guard I would much rather have a Progressive hard wired unit.

 

[pegmikef]

14. Fridge seems to be working OK, but since it only has a "auto" light for running on propane or AC, I cannot say for sure that AC is working.

Turn the propane off and that will tell you if the a/c side is working.

Sorry for your problem, but glad you are both safe and it looks like something that could have been a lot worse if you had not had most of your stuff protected with surge protectors.

 

[boatto5er]

I agree with Jon. Since the probable loose connection was on the "out" end of the EMS, it didn't sense any issue.


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[TravelTiger]

From what I see you had a loose connection at the Surge-Guard receptical. Since you were using a lot of power with a loose connection it got hot and melted. I would say the lug on the bottom was the loose one. I don't like surge guard I would much rather have a Progressive hard wired unit.

John, I think "back in the day" (2010) when we bought the rig, we'd already owned a TT and had the SurgeGuard 30 amp. It seemed natural to get the 50 amp from them as well. Probably price was the deciding factor. In the "heat of the moment" we rushed out to the nearest RV dealer (40 min away) and got what they had, another SurgeGuard, for the time being. But I have placed an order on Amazon for the PI unit.

 

[jnbhobe]

Also check to be sure your load is evenly distributed in the breaker box, I have seen some units with both AC's on one side.

 

[sjandbj]

There was just a conversation going on in another post about portable vs hard wired ems units. I had not given much thought to the advantages of a hard wired system just decided I wanted to take the time to hard wire the unit. These two treads have made me glad i did .

Regards,
Steve


BTW: I live in Las Vegas and it is very common to see the plugs get hot and melt due to poor connections.

"[h=2]Re: Bighorn - Surge protector[/h]

I had the portable EMS from Progressive. This did not protect my RV from an electrical surge of 240 volts. A dropped neutral in the power cord reel, which is after the EMS, allowed 240 volts to enter my RV and caused several thousand $$ damage. The wired my take more time but will protect more."​

 

[swburbguy]

People are always plugging and unplugging with out turning off the breakers. They get burned inside from the load making the receptacles weaker thus causing problems for others . I had a 30 amp one that was weak and almost burned mine up. If the plug doesn't go in hard receptacle could be weak

 

[scottyb]

The most likely cause of burnt wiring is a loose connection. It is rarely due to an overload, which will usually trip a breaker before burning the wires. I agree with the PD over the Surge Guard, whether hard wired or portable.

 

[jbeletti]

Erika - sorry to hear this

I have no ideas on the cause, but sounds like others are hot on the trail.

To my knowledge, the Microwave "should be" on a dedicated circuit. The 2 slides recepts as well as those in the back wall will all be on 1 circuit.

Did something get rewired by you guys or a dealer at some point to to where the Mic got moved to the slide room recept circuit?

 

[avvidclif]

Just a note but the burned connection was on the Neutral lead which has to support both 50A legs. It was loose and overheated. You are lucky in that the trailer could have been supplied with 240v with no Neutral and that would have been expensive.

Note: The less plug in connections used the better. Ergo hardwired unit.

 

[TravelTiger]

Erika - sorry to hear this

I have no ideas on the cause, but sounds like others are hot on the trail.

To my knowledge, the Microwave "should be" on a dedicated circuit. The 2 slides recepts as well as those in the back wall will all be on 1 circuit.

Did something get rewired by you guys or a dealer at some point to to where the Mic got moved to the slide room recept circuit?

No Jim, no wiring done or authorized by us on the AC side. Only thing we've had worked on was the fridge slide, back when we had a minor run-in with a 4ft pole into the jwrap our second trip with it (2010). I guess something could have been swapped way back then... no wiring was damaged to my knowledge, so not sure why it would have been touched. The receptacle by the stove in the kitchen slide is wired to the breaker labeled "Mic", even though it is a GFI plug. Other GFI plugs in the island are on the breaker labeled "GFI."


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[TravelTiger]

Based on responses, a loose connection caused excessive heat to build and melt the plug, which in turn may have caused an open neutral long enough to fry the TV and also surge protectors (and possibly other stuff?) inside the rig. What signs do we look for to verify if the rig suffered any other ill effects? I have to make sure it's safe to live in again!


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[jassson007]

Erica we had same issue with our sob TT but caught ours early enough. Ours melted at the "Marinco" outlet on the trailer though and was very close to burning entire trailer down before power cut out.


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[danemayer]

Erica,

It's very encouraging that there's no evidence of overheated wires at the trailer connection or at the back of the circuit breakers. In your picture, it looks like the neutral prong on your power cord was completely melted down indicating extremely high heat on that connection. To me that suggests high resistance at that point in the connection, perhaps starting as a loose connection on the plug side, or where the plug was inserted into the receptacle. But I'm also suspicious of the TRC device that perhaps the high resistance could have originated with a poor connection inside the TRC receptacle.

As for evaluating the conditions inside, I would use a volt meter to make sure there's no abnormal condition inside. First testing with no loads. Then gradually turning on equipment. If voltage at the pedestal measures 120V, when you check your interior outlets, they should also read 120V between HOT and GROUND, and also between HOT and NEUTRAL on the plugs. The ideal reading between NEUTRAL and GROUND should be 0. If you're reading 2 or 3 volts there, there's a problem somewhere.

I'd also suggest reviewing the OPEN NEUTRAL document here, which talks to testing voltage while adding loads, and the LOST NEUTRAL PRESENTATION here which explains the theory on what happens with a compromised neutral.

 

[TxCowboy]

Erica, so sorry this situation occurred and that all is repaired/replace and up and running soon.

EDITED: Asked a question to the general forum but don't want to distract from Erica's questions. I'll start a new thread.

 

[wdk450]

I make it part of the routine power hook-up process to spray all contacting plugs/sockets with Caig Cramolyn DeOxideIt contact restorer/cleaner spray.

http://www.amazon.com/Hosa-Cable-De...2?ie=UTF8&qid=1439393145&sr=8-2&keywords=caig

http://www.caig.com/

https://system.netsuite.com/core/me...ADAiu4hvWk&vid=RtYjiwADAjC4hjmp&cktime=131840

 

[Gaffer]

Loose, dirty or corroded connection at the point of the melt down. Do you plug or unplug the Marinco connetor into the Surge-guard or any outlet for that matter while the outlet is hot (breaker in the on position)?

 

[TravelTiger]

Loose, dirty or corroded connection at the point of the melt down. Do you plug or unplug the Marinco connetor into the Surge-guard or any outlet for that matter while the outlet is hot (breaker in the on position)?

No we typically do not do that. Another note, we've been basically stationary for the past year, only trip was to Goshen and back, then a week later to this new park. So not much plugging/unplugging at all. This particular connection has the plastic lock box on it, so it doesn't get taken apart. I can see how the lock hid what could have needed attention sooner.

 

[TravelTiger]

Erica,

It's very encouraging that there's no evidence of overheated wires at the trailer connection or at the back of the circuit breakers. In your picture, it looks like the neutral prong on your power cord was completely melted down indicating extremely high heat on that connection. To me that suggests high resistance at that point in the connection, perhaps starting as a loose connection on the plug side, or where the plug was inserted into the receptacle. But I'm also suspicious of the TRC device that perhaps the high resistance could have originated with a poor connection inside the TRC receptacle.

As for evaluating the conditions inside, I would use a volt meter to make sure there's no abnormal condition inside. First testing with no loads. Then gradually turning on equipment. If voltage at the pedestal measures 120V, when you check your interior outlets, they should also read 120V between HOT and GROUND, and also between HOT and NEUTRAL on the plugs. The ideal reading between NEUTRAL and GROUND should be 0. If you're reading 2 or 3 volts there, there's a problem somewhere.
View attachment 39184
I'd also suggest reviewing the OPEN NEUTRAL document here, which talks to testing voltage while adding loads, and the LOST NEUTRAL PRESENTATION here which explains the theory on what happens with a compromised neutral.

Dan, I read this and it seems scary, that we have no way to test this unless we make a special rigged up wiring attachment to test the Park connection before we hook in? I would think if it was a common problem, someone would have a product/professional device to test for it. Not doubting it's possible, but not sure how to address the concern without building the device the article talks about?

Luckily, we are finding no evidence of damage from 240 volts. Today we tested all the outlets in the rig, and checked all devices that had been plugged in at the time of the incident. Every plug read correctly. All devices that were plugged in before, we plugged in individually and appear to be functioning, or at least getting power.

We'll address more tomorrow.