ONAN 5500 Installation

Below are typical installation instructions for an ONAN 5500 Gas/Diesel/Propane with an 8-pin generator wiring harness.

Note: For Step 7 you'll need to purchase 14-gauge electrical wire for the run from our ShorePower Monitor to your transfer switch.


Turn-off your generator AC circuit breakers to avoid interruption of shore power service during installation and testing  of ShorePower Monitor.


Identify the following 4 wires on your generator wiring harness. Use a label or tape to mark each wire so you won't forget which wire is which.

On a typical ONAN 8-pin wiring harness the wires are labeled on the harness as follows:

  • A - Ground - Brown
  • B - Stop - Green
  • C - Start - Red
  • E - Run - Orange

On a typical ONAN 10-pin wiring harness the wires are labeled on the harness as follows

  • A - Ground
  • C - Start
  • E - Stop
  • F - Run

NOTE: The pin connections above are typical ONAN connections. Not all ONAN generators have the same generator wiring harness connections as some may have been changed by the dealer or RV manufacturer. Ensure you have properly identified the 4 wires correctly before proceeding with Step 3.


Connect one Posi-Tap to each of the 4 wires identified in Step 2. 


Make the connection from the ShorePower Monitor to the Posi-Taps (wiring harness) as per the wiring diagram provided.

  • Green wire to [E] STOP
  • Red wire to [C] START
  • Brown wire to [A] GROUND
  • Orange wire to [F]RUN

Make sure to connect the correct wires to the wiring harness as we use red-colored wires more than once.

On our installation photo we used white wires to extend to the harness due to location of our unit. The closer the installation of our unit to the wiring harness will allow you to use the supplied 4-foot wire length we provide.


  • Connect the red wire from the ShorePower Monitor (I3) to one side of the enable switch using the supplied Posi-Lock or a crimp connector.
  • Connect the second red wire (provided in the zip-lock bag) to the other side of the enable switch. The other end of this red wire will eventually be connected to your positive battery terminal.


  • Connect the red wire from the enable switch and the red wire from (L+) on the ShorePower  Monitor to your +12 VDC (Positive battery terminal).
  • Connect the black wire (M) on the ShorePower Monitor to ground (any metal on your RV).


From the ShorePower Monitor Power Converter (See wiring diagram B - Transfer Switch Connection): You'll need 14-gauge stranded electrical wire for the run from our unit to your transfer switch. 

  • Connect  (L) on our MeanWell Power Converter to one side of the 110 Volts on the transfer switch.
  • Connect the (N) on our MeanWell Power Converter to the center connection (common) on the transfer switch


The ShorePower Monitor & the MeanWell Power Converter should both have their green light ON, if all the wires, including the wires to the transfer switch,  have been properly connected. .

  • To test the unit Turn ON the ENABLE Switch and disconnect from shore power. The green light on the MeanWell will go off and in approximately 20 seconds our unit will auto-start your generator.
  • Let generator run for about a minute then re-connect to shore power and our unit will automatically shut-off your generator in approximately 10-12 seconds. The green light on the MeanWell will come back on.

IMPORTANT NOTE: Turning the ENABLE SWITCH On or OFF does not affect the green light on the ShorePower Monitor or MeanWell. IF the ShorePower Monitor is properly connect and you have shore power those two light will always be on. The ENABLE SWITCH simply enables or disables monitoring.


This is what a typical set-up will look like once it is finished. You can view other customer installation photos by clicking here.

Onan 5500 Installation Guide