120 to panel but nothing works

Had a GFI fail, would not reset. Replaced and all was right again.

ramyankee wrote:
How about a tripped GCFI plug?

+1 Check these 1st. Normally located next to a sink.

How about a tripped GCFI plug?

I had a very similar incident when we were in Texas last spring. I had 120 at the panel, but every time I tried to operate something with it, the 120 disappeared. I checked all the internal 120 circuits for shorts and loose connections and they were all ok. I finally checked the shore power cable, where it connects in the junction box. I found that vibration had worn the wire nut insulation on the neutral and it was grounded to the box. Since it was after dark, I made temporary repairs and our 120 was working again. I made proper repairs to the connections the following morning.



When I opened the junction box, this is what I found.

If you find most of the 120VAC items are indeed working in your trailer and only no 13.6VDC on your battery terminals when connected to shore power then your CONVERTER/CHARGER unit may have failed. The most failed component in this line is an in-line fuse that is very close to the battery terminals may have. This will happen if during the time the converter/charger was trying to keep your battery charged up and the battery experienced a shorted cell. This would draw alot of power from the converter/charger and may blow its output fuses. Sometimes this may trip the 120VAc breaker for the converter. Normally the converter/charger will produce 13.6VDC at its output terminals near the 12VDC section of power distribution panel. This 13.6VDC then connects directly to the battery terminals where you can measure it at the terminals itself. If you measure 13.6VDC at the converter/charger unit and not at the battery terminals then there is either blown fuses or bad connections between the two points.

having an inexpensive multimeter available from Lowes/WALMART/Any number of auto parts stores ($7-$20) is most helpful troubleshooting AC and DC problems...


Finding a totally DEAD Battery points to battery failure to me. Was their any fluids in the battery when you checked it. Did you find any cell bone dry... You did say however you got some life back into the battery however with a portable battery charger.

Roy Ken

This is an Electrical Block Diagram of a typical 30AMP Trailer



Assuming you are plugging into a standard camp ground 30A Pedestal with just your 30A Shore Power Cable.

Look for these problem areas.


Look close at the 30AMP Connector for signs of ware or burned contacts


Finding these burned areas on the camp ground connector can easily destroy your 30AMP Shore Power Connector plug. This 30AMP Plug is destroyed and will need replaced.


Now check the other end of the 30AMP Shore Power Connector
Some shore power cables connect to a screw on power plug on the side of the the trailer. My shore power cable pulls out of a hole permanent connected on the inside of the trailer only available to inspect by pulling some panels inside the trailer.


Check the end of the disconnected type shore power cable. If you see burned signs like shown here the cable end needs replaced


On the inside of the trailer this 30AMP Shore Power Connections goes straight to the Power Distribution MAIN 30AMP CIRCUIT BREAKER. It could have bad connections but this is very rare. The 30AMP Circuit breaker may be tripped or bad. You can easily remove the circuit breaker for inspection and if you think it is bad take it with you to LOWES and get an exact replacement.

Typical 30AMP Circuit Breaker


There really isn't too much between the shore power connection on the pedestal and the 30AMP Circuit breaker in your Power Distribution Panel that can go wrong.

I am just poking around in the dark here for you. Not a whole lot of information from you to digest...

Let us know what you have checked or perhaps any other hookup information you have done. Possible you may have one of these SURGE PROTECTOR in-line which has a RESET button on it..


Perhaps you are using adapters and extension cords and plugged into some 120VAC 15AMP receptacle...

AS shown in the very top BLOCK DIAGRAM the 120VAC goes straight thru your power distribution panel and connects to all of your 120VAC appliances, outlets, etc. Since you lost 12VDC charging capability it seems that the 120VAC feeding the on-board converter/charger has failed. It would be interesting if the outlets and other 120VAC Appliances have also failed.

Please note the ceiling lights in the trailer only operate from the 12VDC line not the 120VAC line. So flipping on the ceiling lights and finding them not working does not necessarily mean you have lost your 120VAC.

Lets us know whats happening - lots of smart folks on here to help...

Roy Ken

I'd use a meter and follow the circuit til the power stops and look for bad components along the way. The common things are bad plugs/cordcaps/receptacles/breakers and any kind of connectors. Craig

Have you checked for thrown main breaker at panel.