Can Progressive Dynamics Transfer Switch PD52 Have Shore Power on Normally Closed Connection

Updated 01/22/2021 | Published 01/20/2021

Question:

I purchased this product from you and had it installed on my previous RV. Now I am moving it to my new RV and had a question. The wiring diagram shows typical installation as having shore power come in via the Normally Open connection and the inverter come in via the Normally Closed connection. So that, when shore power is applied, the relay energizes to allow shore power to be applied to the RV and, when no shore power is present, the relay is de-energized and allows inverter power to pass through the to the RV. I am thinking that I use shore power much more than inverter power and feel it would be more efficient to have shore power be on the Normally Closed position so that the relay spent more time in the de-energized position. I dont see any negatives to this but thought I would ask just to be sure. Even in the event that power was on for both at once, only the inverter power would pass to the RV but I always turn the inverter off.

asked by: Mark C

Expert Reply:

I reached out to Progressive Dynamics to find out if you could have the shore power on the Normally Closed position for the Progressive Dynamics Transfer Switch # PD52, and this is what I was told via our tech contact:

"I think there is confusion here; the PD52 uses two normally open contactors not a single relay with normally closed contacts in the inactive position as with the PD51. Second, the RV transfer switches are designed as "Generator Priority" that means that whenever AC voltage on the generator input is detected the automatic transfer switch (ATS) will activate the generator contactor or the relay and pass the AC through. This will disconnect the shore input on any RV ATS. When the AC power is removed from the generator input of the ATS then the power available at the shoreline input is automatically routed to the output."

expert reply by: Kyle S