120 Volt Breaker Issue

The Canadian version of the 03 Komfort has the MW and water heater on the same 7355 circuit and the one breaker, but there is only the one black wire going to the bottom of that breaker. There is another wall switch that has three positions for the WH and MW, which are : WH, Off, MW.

The USA version of the 03 Komfort 7355 does not have that, but has a different arrangement for the 120v breakers, and uses 20s instead of 15s a lot.

Perhaps the now gone RV had something like that with a downstream switch between the MW and the fridge, away from the single breaker.

EDit--ok forget that, the MW had its own breaker.

And just to explain it a different way. All breakers are on.

Turn off microwave breaker, microwave display goes out.

Turn off refrigerator breaker, microwave display goes out and refrigerator 120 volts outlet is dead. Verified because refrigerator switches to gas mode.

And since the refrigerator breaker is tied to both outlets for the refrigerator and the big convection oven/microwave this 15 amp breaker will trip occasionally. Which my guess is if the 300 watt refrigerator heating element happens to be on at the same time the microwave is in use it trips.

Not on the Komfort, was on visiting rig. Correct?
Sounds now like it is a loose or open neutral on a fifty amp rig.

So it is a two pole breaker and each has separate romex.....

Any chance the microwave and fridge are plugged into top and bottom of the same duplex outlet?

I would remove both romex (hot) and verify power and breaker function with a multimeter or voltage detector. Post the results but I think it will check OK. Then attach one romex to one breaker and see if it back feeds on the other romex. Then swap and check the other direction. Post the results.

Need to divide and concur. Test each section separated from others. Otherwise it is just a swirling mystery.

time2roll wrote:
So it is a two pole breaker and each has separate romex.....

Any chance the microwave and fridge are plugged into top and bottom of the same duplex outlet?

I would remove both romex (hot) and verify power and breaker function with a multimeter or voltage detector. Post the results but I think it will check OK. Then attach one romex to one breaker and see if it back feeds on the other romex. Then swap and check the other direction. Post the results.

Need to divide and concur. Test each section separated from others. Otherwise it is just a swirling mystery.

No two pole breakers in this panel. Each appliance has it's own outlet on different sides of the motorhome.

OK and somehow they are cross connected to act the way they do.
Start disconnecting something and checking where the power flows.

Should be easy if these are dedicated circuits. If they serve multiple outlets they may need to get mapped and wire connections checked at each point.
Systematic elimination will find the issue but have to start separating things.

Sounds to me like a couple wires in that Sub Panel are crossed (that is hooked up wrong)

NOTE: Caution, you will be working with HOT wiring, SHOCK hazard, Take precautions or get someone who knows what the blazes he's doing (IE: ME) to do these tests... I also have the hardware.

how to test, You need a 120 volt test light or multi-meter. I like test lights cause they are "Quick and dirty"

Turn off ALL breakers in the box.. One probe to the white wire bus You can even screw it down if you like (makes it easier to do this test)

now probe the black wires

IF any wire connected to a breaker is "hot" that is your problem NO breaker wires shoudl be HOT

There is also supposed to be a black wire hooked to a bus bar.. The bar the breakers connect with (A black wire not connected to a breaker) This one SHOULD be HOT. if it' snot, your box is mis-wired.

If you are in S.E. Ga.. So am I.

Obviously something is wired wrongly, but you know that already.

The 30A breaker from the inverter--does it really and truly go to the inverter (or its associated transfer switch)?

I would have guessed that the two-way fridge would be one thing that should not be run from inverter power typically. A residential compressor fridge is, of course, a different matter altogether. I would probably tackle this problem by removing all power from the system, turning off all the breakers, and using a meter or signal tracer figure out exactly what is connected to each of the breaker outputs. It might be a bit of a forensic search.

It would be nice to know the make and model of the rig on first posting.

trailrider wrote:
It is a 30 amp sub panel fed from the inverter. I already took the cover off and verified that each breaker is wired to it's own separate romex. Once those romex leave the box I have no idea what happens down the line.

Previous owner added sub panel and inverter
And tied it to pre-existing fridge circuit

My guess is he never used 120v for fridge
This left the circuit available for the MW when using generator or inverter

Check wire size on the primary 15 amp breaker that trips
If it is 12ga wire, you can replace that breaker with a 20 amp breaker