Fried 2000 WATT Inverter. Has this happened to you, if not, don't !

[JOLT]

I thought for sure that if I overloaded the system a breaker would break as it had done before but not this time.

Winter time in MD on 50 amp service and running two 1500 watt space heaters as supplemental heat with temp below 35 degrees.  We ran one up front on one GFI leg and the other in the bedroom using the other GFI leg.  The coffee pot was on a timer and when it went off at 5 am with both space heaters running while running the whole house fan to circulate the heat it fried the inverter.  It is amazing how we learn. 

I was told by the tech at the dealership here in MD it was because the wire cap (s) had come loose.  I think it was overload and the shop foreman agreed but you would think that a circuit breaker besides the GFIs would have popped first.  The two GFIs had popped and could not be reset.  Everything else in the Journey worked except those items running on 110 electrical outlets plus the TV.  The gas furnace, electric hot water heater, refrigerator on electric and satellite all worked as normal. 

After ours was diagnosed and fixed, a week later another Winnebago came in with the exact same problem. 
Makes a blue flame heater an option if staying long term in below freezing weather.  I have since had installed an Extend-a-Flow kit along with a 20ft high pressure hose and use an external tank. 

Click on the pictures to enlarge.

 

[Ned]

If those were all inverter powered outlets the circuit breaker on the inverter should have tripped once the load went over 20A.

 

[geodrake]

Sorry about your loss Jolt.  Like Ned; I don't understand why the breakers didn't protect things?????

 

[JOLT]

Ned and geodrake,
I have to remember to Trust but Verify.  I also thought the breakers would protect me but now I have verified it didn't and won't. 
These were all inverter powered outlets so it does not make sense to me.  I would have thought that a coach breaker under the bed on my Journey would have tripped.

 

[John Canfield]

Your Dimensions charger/inverter doesn't have ..ahem.. the best reputation  : and I would not draw any conclusions based on your series of events.  The first area my finger of blame would be pointing to is the Dimensions.  I strongly recommend you replace it with a Xantrex product.

 

[Ned]

That push button breaker on the panel visible in the second photo appears to be labeled "Output Breaker".  I can't read the rating, but it should be 20A and should have opened up long before any wiring burned.  Especially with those loads you listed.  I can also recommend a Xantrex as a replacement.

 

[Harry B]

It is a 30A breaker. We have tripped that one on several occasions. What puzzles me is that the inverter was not even in the circuit due to having 50 amp service available.
When shore power is available, the Dimensions inverter is bypassed by the internal relay. However the arcing caused by the bad wire nut connection can cause voltage spikes and consequently damage the inverter.

 

[SargeW]

I think Harry is right, I don't get what the inverter had to do with anything.  I too run two electric space heaters in the below freezing temps we have been in.  And I had experienced the same issue as Jolt in the exact same way.  The DW plugged in the coffee maker and the 110 circuit breaker tripped.  I moved the heater to a different plug, reset the breaker and life went on.  The inverter should have had nothing to do with it.  I am perhaps a fortunate one but my 2KW Dimensions inverter is still working perfectly, and I use it often while dry camping.  Not that it won't die someday, but after 4 years it's still going fine. 

 

[John Hilley]

The power "passed thru" the inverter, that would make the coach breaker panel the point where it would trip on over current. you probably didn't draw enough current to trip the breaker. A poor or loose connection with the wire nuts over heated to the point that the connection failed open. Had it burned the insulation to the point it touched a neutral or ground it would have tripped. This type of failure is the worst type as it could have started a fire. Doesn't hurt to periodically check for loose wire nuts.  I usually tighten and then wrap with electrical tape to prevent loosening from vibration.

 

[Ned]

Even though you have shore power, the circuits on the inverter are still connected to that circuit breaker on the inverter.  They're powered through the internal transfer switch rather than the inverter output, but still go through that breaker.

 

[Lou Schneider]

It looks to me like the neutral line is the one that burned up.  The neutral can carry excessive current if you draw a heavy load while plugged into a 120 volt only feed instead of the normal 120/240 volts that supplies a 50 amp outlet.

When you're plugged into a normal 120/240 volt feed the two legs are out of phase with each other and the neutral carries the DIFFERENCE in current between them.  If you pull 20 amps on one leg and 15 amps on the other, the neutral carries the difference, or 5 amps.  If you pull 20 amps on both legs, the neutral current is 0.  Either case is OK and won't blow the 20 amp breaker on the inverter.

But if you're plugged into 120 volt only service, the neutral carries the SUM of both leg currents.  20 amps on one leg and 15 amps on the other will give 35 amps on the neutral.  You still won't blow a 20 amp breaker on either leg, but since the neutral through the inverter is wired with 10 gauge wire (the orange Romex jacket indicates this) the neutral wire is well over it's 30 amp limit.

If you draw a full 20 amps on each leg, the neutral is carrying 40 amps and is even more severely overloaded.

Since the neutral has burned up, while neither hot feed shows excessive heat, I suspect you pulled a heavy load through the inverter outlets while hooked up to 120 volt only service.

This can happen if the park pedestal is incorrectly wired, with 120 volt instead of 120/240 service.  Or it can happen if you use that adapter that lets you split a 50 amp plug into a 30 and 20 amp socket.  Usually there's only 120 volts available in a 30 amp pedestal, not 120/240.  In either of these cases, you're limited to a total of 30 amps between both legs (15 amps on each, or 20 amps on one and 10 amps on the other, etc.) without overloading that neutral.

 

[Jack Nichols]

Thought for the future.  I bought a fancy LCD readout tower heater, and it freaked out my Xantrex 2K inverter. It tripped the breaker on the inverter itself, and took a while to find. 

I discovered my coach had been wired with a separate circuit that bypassed all the coach systems, (labeled 'not integrated") and used that into a 20 amp circuit on the power bush outside.  I used the circuit breaker on the panel to protect the circuit, as I do not think that line has any fuses or breakers in it.  That ran both little space heaters just fine, and kept me comfy down to 20 degrees or so.  If a coach is not so wired, a separate extension cord through a window or door could be run to achieve the same effect.

 

[SargeW]

So even with a bad transfer switch, or a mis wired pedestal, the inverter wasn't at fault.  The inverter may have been the victim, but any inverter in that position may have suffered the same fate.

 

[Neal]

Ned and geodrake,
I have to remember to Trust but Verify.  I also thought the breakers would protect me but now I have verified it didn't and won't. 
These were all inverter powered outlets so it does not make sense to me.  I would have thought that a coach breaker under the bed on my Journey would have tripped.

When we tripped a 30 amp breaker while using 2 electric heaters, we moved one of the heaters to the washing machine circuit and cured our problem. Just have to remember to not run that heater & the washing machine at the same time.