Breakers, GFCIs and the EMS

One tripped GFCI can kill outlets all over the coach. Find every GFCI before you chase wiring.

The short version

• GFCIs feed outlets downstream. The bathroom, outside and kitchen outlets are often on one GFCI.
• A GFCI that trips again right away has a real fault. Unplug everything and add things back one at a time.
• An EMS (surge guard) shuts power off for low voltage, high voltage, open ground or reversed polarity. Read its code.
• Don't bypass the EMS to get power. It's telling you something.

On the job

1. GFCI trips: unplug everything on the circuit and reset. Holds = an appliance. Trips = wiring or a hardwired load leaking to ground.
2. Ohm each heating element (water heater, fridge) to its case: O.L.
3. Breaker trips instantly = short; after a while = overload or a hot connection. Clamp the load against the rating.
4. EMS code: read it. Fix the pedestal or move. Don't bypass it.

Numbers

• GFCI trip: about 5 mA of leakage

Shop tip

Check the GFCI in the kitchen, bathroom AND the one hiding in an outside compartment.

Try it on a service call

Put the lesson to work on a hands-on troubleshooting case.

• Bathroom outlets are dead

Keep going on 120V and shore power

Learn it

• Shore power: 30A vs 50A
• The lost neutral (50A danger)
• Transfer switches and generator power

Prove it

• Half the coach is dead
• Bathroom outlets are dead
• Lights surge and the microwave died
• Shocked at the door handle

On the job

• 120V system
• 50A power problems