wdk450
Well-known member
I have a pure sine wave inverter system instead of a generator. Progressive says not to run inverter power through EMS. So my EMS is shore power only, pre-transfer switch. When I had the EMS open to switch out the p.c. logic board (with Progressive's permission/help) a couple of years ago, I took the opportunity to treat the high current contacts with Caig Cramolyn DeOxit electrical contact cleaner/restorer. I did the same for the transfer switch high current contacts while I was in the crawl space.
I switch my power sources with no load when connecting/disconnecting shore power by switching off the mains inside breakers before disconnecting/connecting shore power. This makes any load arcing happen on the circuit breaker contacts. The circuit breakers are easily accessible, and readily available at home improvement stores. I even have a new spare mains breaker in my spare parts supply.
In my career as a hospital electronics tech,I have never heard of relay contacts being affected by switching no loads. I can think of very low current communications relays that switched hundreds of times a minute (low current teletype circuits from my Navy days) that worked for years on end without failure. I compare that to a bunch of EKG carts throughout the hospital that had 2 - 12 volt batteries that were charged in parallel when the cart was plugged in, and powered the carts in series when the carts were unplugged, a high current relay providing the necessary circuit switching. After a year or two of use, these carts ALL had these relays failing at the contacts. Many times when I didn't have a new relay in stock, I would open up the relay, file the contacts, and spray them with DeOxIt spray and they would work for another year.
