30A to 50A Adapter Causes MH Fire

[hawk57]

Just don't use adapters. Match your coach to the electric service and choose your parks according to what you need. Anything else is asking for it and could result in denial of fire insurance in any state that has negligence statutues to determine fault for such fires and damages.

[Adaycj]

Wow. As a licenced electrician I am very worried about some of the concepts in this thread.

A circuit protected by a 50A breaker has enough current capability to cause a fire. So does a 30A, 20A, 15A circuit. Just think of paper, plastic, or anything else that can burn touching the element of an electric resistance heater. The fire in this case likely had nothing to do with an overloaded circuit that had an excessive amount of current flowing through it. The connections at an adapter may have been the source of the heat that caused a fire, but it really makes no difference which connection. Any connection, on a 50A plug or a 30A one, could have made the heat to start the fire.

An open neutral in any part of an othewise properly wired 50A coach does not cause 240v to flow, not anywhere, not at all.

Circuit protection (circuit breakers and fuses) need to be sized according to the wire used. The circuit protection can be anywhere in the circuit, and it will protect the circuit if excessive current flows through the protection device (circuit breaker).

The only thing "out of the ordinary" with RVs is that sometimes we use wire rated for 30A connected to a 50A breaker (with adapter). It is normally not a concern because there is a 30A breaker in the circuit too. If the circuit has a low resistance failure of more than 30A but less than 50a before the 30A breaker there will be trouble. It is a known risk and does not appear to be the trouble in this fire.

Plugging a 50A or 30A RV into a lower rated circuit on a pedestal, home, or business is not a problem. The power from the pedestal, home, or business already has circuit protection small enough to match the rating. If they do not it is a failure of the pedestal, home, or business not the RV or adapters.

[Cubey]

Originally Posted by wjell

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This is what I'm getting out of this. The coach knows it can handle 50A. It will allow more than 30A be be used? Therein lies the "danger" when only 30A is available?

That being said, the pedestal 30A breaker SHOULD HAVE tripped when the demand got to be too high?

If it was a problem with pulling too much, yes, it should have. I think you should always be careful about not running too much in any RV unless you have personally rewired every inch of wire in it safely and know what it's capable of handling.

A local RV store has a BADLY burned out 120v 15A outlet from inside of an RV where someone was running an electric heater (or two?) on it. They leave it on the counter as a warning about trying such things in an RV.

I replaced two of the old original outlets inside this van so far and the one outside outlet since they were 35 years old and a bit worn out. The other 2 I will be replaced sooner or later but they aren't worn out (ie: loose when you plug in something).

[FlyingDiver]

Based on the evidence so far, I'm betting this has nothing to do with an overcurrent situation. My guess is that the coiled cables caused an inductive load which overheated them and melted the connector. As wa8yxm pointed out in post #23, coiling the wires will cause them to heat up. Leaving the power cord coiled up under load is a bad idea.

[wanderso]

Many factors could lead to this issue and circuit breakers are no safe guarantee of avoiding a fire.

In my stick and bricks, a contact at our dryer socket in the wall had worked its way loose but still connected enough to function. Dear wife noted that the dryer smelled "hot" and had stopped working. Upon investigation, the dryer socket was fried. At the power panel, the circuit breaker was also fried and - wait for it - the breaker never did trip. It just burned.

Greater scary thought: my 200 amp service in this 45 user old home has no main cutoff switch at the time - it was a dual bus panel with the 220 service always live and one main for the various 120v circuits. Fire at the time was a real possibility.

After confirming the wiring as still safe, at the time we replaced the circuit breaker and dryer receptacle.

Since then, we have replaced the entire panel with modern service. A new bedroom also includes the new code required circuit breakers that are AFCI (arc fault circuit interrupter). http://en.m.wikipedia.org/wiki/Arc-f...it_interrupter I am glad to have it installed and wonder if RVs will ever follow suit. Seems odd that we care about this in homes, but in much more flammable RVs, we do not have this same protection. I say that this should change, even for 12V circuits if possible.

In this case, the fire likely would have never happened.

[Cubey]

The thing about RVs is I *think* they don't have to conform to the same electrical safety standards as homes do. Someone please correct me if I am wrong.

[gemini5362]

Originally Posted by Cubey

Yes, that's exactly what I said.. so I don't know why you're trying to explain it in even more complicated terms.

I'm not at anymore risk for fire than if I was plugged into a 30A receptacle unless I was stupid and tried to run two or three 1500W electric heaters at the same time. I am running as much electricity through the system as a 30A system allows.

Unless I try to pull over 30A, I'm not at any risk for fire. Outlets push VOLTAGE out through the cord, but not AMPERAGE without a load on it. An appliance has to demand amps/watts before cords begin to heat up. Idle or under utilized circuits generate don't catch fire unless there is some kind of a short, then it's a fire hazard no matter what.

You could plug a 100ft 16 gauge 120v outdoor cord into a 50A outlet with adapters and there would NEVER be a fire, even if you left it that way for 20 years. Assuming you don't try to pull more than a few amps through it that is! If you try to pull more amps through it than it's designed for, then you have problems.

So no, simply having it plugged into a 50A outlet is not a fire hazard. Overloading the van's electrical system beyond 30A with appliances, tools, electronics, whatever else... would be.

Which goes back to the original post... it sounds like they tried to pull more than 30 amps through a 30A cord and adapter which is a big no-no! They overloaded their cord. I am not overloading anything. I am using my van's electrical system exactly within the specifications it was designed to be used.

The closest I might come to this is using a 20A to 30A adapter. In which case, the fire hazard would be outside at the pedestal since the adapter or outlet is what would become overloaded, not my van's electrical system.

Oh, and I have two fire extinguishers so far. One inside the van, one outside in a compartment. I will be getting a second for the interior at the bed.

that is very wrong. There are hundreds of home fires every year for this very reason. You are correct if you can keep your useage under 30 amps. The size of the wire should ALWAYS be able to conduct more current than the breaker is sized for. and what happens if you get a high resistance connection that is pulling an additional current to where you are now pushing 45 amps or let me just point out that 50 amp breakers do not trip at 51 amps nor at 52 even. You could be drawing 50 amps for a while before that breaker trips. And what is happening with your 30 amp cable it is getting nice and hot. I hope that i do not camp next to you or someone with that opinion. And if you do not believe that can happen. I rewired my house after I bought it. I did not get one of the wire nuts tight enough hooking up the dining room light. A couple of years later the light went out one night. I replaced the bulb and it still did not work. I went up the next day and was easy to find the problem the wire because it was not making a solid enough mechanical connection was a high resistance joint. After getting hot and cooling down when switched off after enough time it finally got hot enough to melt the wire nut and burn the wire. Luckily for me it was in a metal box and could not catch anything on fire but the breaker never tripped once. Of course I size my wires to carry more current than the breaker so the wire itself never had any problem with the additional heat just the connection.

[gemini5362]

Originally Posted by 96 Wideglide

I said the same thing on this forum several months ago, and was corrected by many, that this is standard procedure with 30A coahes connected to 50A pedestals .

I do not care how standard it is. It is wrong and dangerous

[gemini5362]

Originally Posted by steveclv

Cubey - I guess I am a little confused too.

If you are a 30amp connection and plugging into one leg of a 50amp supply then you are not protecting your circuits at the pedestal - that is a 50amp circuit breaker but your plug and cable are only rated at 30amps.

See the problem?

I do not believe he sees the problem or even thinks there is one. What is really scary is that I noticed he is from the same state I am from. We have a lot of good campgrounds in Arkansas and I have a motor home so I almost always go to the 50 amp service sites. I could be camped next to him and not know it. Now that is scary.

[gemini5362]

Originally Posted by hawk57

Just don't use adapters. Match your coach to the electric service and choose your parks according to what you need. Anything else is asking for it and could result in denial of fire insurance in any state that has negligence statutues to determine fault for such fires and damages.

There is nothing wrong with taking a 50 amp cable for your coach and using an adapter plugging it into a 30 amp service at the pedestal. All the components are rated higher than the service breaker. The problem is the reverse taking components that are rated for 30 amp and plugging them into a 50 amp breaker.

[Cubey]

Originally Posted by gemini5362

I do not believe he sees the problem or even thinks there is one. What is really scary is that I noticed he is from the same state I am from. We have a lot of good campgrounds in Arkansas and I have a motor home so I almost always go to the 50 amp service sites. I could be camped next to him and not know it. Now that is scary.

The chances are so slim that it's not even a risk worth considering. [moderator edit] so you can hurry up and get it over with.

I have a pretty good grasp of electrical safety and wiring so I am not fearful of it the way you seem to be. I do all my own brake work too... but I know what's safe and what isn't.

We drive with huge tanks filled with gasoline or diesel. In a wreck it could ignite and you could burn to death. But you still put fuel in your vehicles, right?

Your propane tanks could rupture in a wreck and you could be blown to bits if the gas ignites, but you still fill them right?

Your batteries could explode in your face but you still have them, right?

It's all possible but the chances are slim so we take the chance. And statistically it's a chance worth taking since that's what you have to do to acheive a goal of driving somewhere, having propane for your stove, starting your engine and storing electricity for power when not hooked up to the grid.

Of all the dangers of RVs, a 30A cable plugged on a 50A pedestal is one of the least likely dangers assuming your cords, adapter and wiring isn't damaged and you don't do stupid things like trying to run 50A on it.

[JohnBoyToo]

I too read that and wondered why ?

Yes, you say you have it figured out, but you have the pieces to do it what others consider the 'correct' and safe way... so why not ?

As some have alluded to, the adapters and/or the wiring being coiled is probably the problem...

sometimes I see people treat these adapters as if they are indestructible - fold them - bend them too tightly, etc...even the 50 amp cord should not be forced into a tight coil --- it's not designed to do that

eventually enough strands may break and you have a lot of power going through what is effectively too small a gauge of wire...

good luck and be careful out there... it's supposed to be fun

[Tarheel]

I also witnessed a similiar fire this past winter at my winter resort in Florida. In this situation, the pigtail was outside the coach and as I'm sitting on my patio someone yells "fire". When I got there to investigate, the adapter was flaming. The connection was laying on the ground and fortunately the grass around it was green. The individual with me cut off the breaker and unplugged the cord. It flamed a few minutes until we threw some water on it. The people were at another site and if their connection had been made in a compartment, I'm sure they would have lost their coach. Both air conditioners were running at the time, but after the owner arrived, everything in the coach was still working.

I learned a lesson myself because I have been guilty a few times in the past of making that connection in my compartment if I had to use an adapter. Mostly when I was loading my coach at home in preparation for a trip.

[Walter5555]

I was at a camp ground once where the 30 amp outlet would not work but I had a 30 to 50 amps pig tale so I use it because all I would get from the 50amp pig tail was 30 amps all was well but if it was the other way around using a 50 amp connected to a 30amp outlet Well now that is a horse of a different color.
A lot has to do with the way the R.V. PARK has it pedestal hooked up.
Just a thought.