Just installed the PI EMS-HW50C in our new 8289WS today. It fits in the compartment behind the Power Panel with no problem.
Straight forward installation, and I placed the remote right above the Power Panel, where I can check it from outside the door on initial connection.
Also removed the OEM Converter (that was a trick, without removing the Furnace) and replaced it with a PD-9260 with remote pendant. The Pendant fits inside the Power Panel on top of the DC Fuses with no problem.
Here is a link to the best price that I could find at the time for the PI Surge Protector.
RV Electrical - Surge Protector | Power Protection - MakariosRV.com
2013 Rockwood 8289WS
Mods: Central Vac, PI EMS-HW50C, 2025RV, (2) SCS225 Trojans, PD9260, Awning Remotes & LED Lights, Eliminators, External Water Filter,, Intellijacks
2008 RAM 3500 Cab&Chassis Hauler Bed, B&W Companion Hitch
All My Modifications are at this link: