Electrical Transfer Switch?

[SlowPoke]

When connecting to shore power, I recently experienced a 15-minute delay waiting for power to energize my motorhome circuits. When I first experienced this, I began checking breakers and testing for power at the pedestal. Everything checked OK, but a loud sound from the generator area (like slapping your hand down hard on a table) was reported by someone outside.

The delay has ocurred several times, but I have not heard the slapping sound again. When I turn the generator on everything operates normally. Is there a switch/relay that will accept 110V from either the generator or shore power but not both?

[wolfe10]

When connecting to shore power, I recently experienced a 15 minute delay waiting for power to energize my MH circuits. The first experience with this I began checking breakers and testing for power at the pedestal. Everything checked OK then a loud sound from the generator area (like slapping you hand down hard on a table) was reported by someone outside. This delay has occurred several times but I have not heard the slapping sound again. When I turn the generator on everything operates normally. Is there a switch/relay that will accept 110V from either generator or shore power but not both?

YES, if you don't have to plug your shore power cord into an outlet powered by the generator for the coach to operate on the generator, you have an ATS (Automatic Transfer Switch).

Locate it by following the shore power cord from where it plugs into coach "downstream" toward the coach breaker box OR follow generator 120 VAC output and it will lead to the same location. Same for following the 120 VAC line from 120 VAC breaker box "upstream" toward generator/shore power.

With all power off INCLUDING AN INVERTER, they are not difficult to replace if you are SAFE WORKING WITH 120 VAC CIRCUITS. Before replacement, with all power off, remove the lid and check for loose connections.

Brett Wolfe

[tbutler]

In most motor homes there is a large (6" x 8" or so) gray box somewhere in the basement which is a power transfer box. If it has been an instantaneous change in the past for your motor home but is now delayed, it indicates a failure of the electronic components which sense the source of the power and make the switch without delay or interruption. There are many varieties of these switches. If you replace yours, find the exact replacement. I replaced one once that had a momentary interruption with each transfer and it meant resetting every clock in the motor home!