Get to Know Your Electrical Components

Locating your power distribution, grounds, and service panels

Your ambulance is designed to support your crew no matter where your calls take you. Understanding where and how your electrical components are housed can assist your team if any of your lighting or equipment needs troubleshooting. From power distribution to grounds and service panels, knowing your way around your truck’s electrical components can eliminate truck downtime should issues arise.

Your Junction Box

Your junction box can be found behind the driver’s seat in your truck cab. The junction box is where the main power comes into the cab and is distributed to the inverter cabinet and electrical panel in the rear.

The main power from the battery goes to the battery side of the InPower battery switch. The power for the inverter/charger is attached here using a 150-amp mega fuse. And the ground for the inverter is attached to the ground bar.

The battery hot fuse blocks and breakers are also attached here. On the timer/load side of the InPower battery switch the power going to the electrical panel in the rear is attached here. You’ll also find attached here the timer/load side fuse blocks and breakers.

All fuses, breakers and relays in the junction box are clearly labeled.

Your Inverter Cabinet

Your inverter cabinet is located in the front bulkhead above the HVAC cabinet in the pass-through area to the cab.

The inverter cabinet has the inverter, battery charger, shoreline breaker box, shoreline indicator relays, and the medical power isolator for the 12-volt outlets.

Your 12-Volt Power Distribution

Your main 12-volt power box containing a 250-amp fuse is located at the driver’s battery on Type 1 trucks and in the battery compartment (with the second battery) on Type 3 trucks.

1/0 cable is run from the fuse to the electrical box behind the driver’s seat. It is attached to the InPower battery switch on the battery side.

Power is switched to the load side when battery switch is on. 1/0 cable runs from the load side of the battery switch to the electrical cabinet in the patient compartment’s action area.

Power goes to two 100-amp breakers and then to the VMUX nodes.

Your 12-Volt Main Grounds

Main grounds go from the ground strip in the electrical box behind the driver’s seat to the chassis frame behind the cab on the driver’s side.

Also, from ground strip in the electrical cabinet in the action area to the chassis frame behind the cab on the driver’s side.

Ground from V-MUX nodes goes directly to chassis battery.

Your Rear Electrical Service Panel

Located in the rear action area above the counter behind the switch panel door, the rear service panel contains the VMUX multiplex system nodes, fuse blocks, relays and breakers.

The battery fuse blocks, load/timer fuse blocks, relays and breakers are all labeled.

The VMUX nodes have paperwork with them that gives all the inputs and outputs labeling. It

gives the locations and wire colors going into the nodes and their description.

Your 120-Volt AC Power Distribution

Shoreline receptacles are mounted on the outside of the ambulance.

10/3 wire from the shoreline receptacle run to the house breaker in the inverter cabinet.

And then from the house breaker to a 120-volt outlet. (This outlet only has power on it when the shoreline is plugged in.)

The inverter/charger is plugged into this outlet.

The 120-volt outlets are plugged into the GFCI outlet on the inverter. All the 120-volt outlets are daisy chained together with 12/3 wire.

Any other HVAC that is powered by a separate shoreline also comes into the inverter cabinet to a separate breaker and out to the system.

Your electrical components play a major role in the functionality of your truck. Getting familiar with their location, components and purposes will help you troubleshoot any electrical issues. As always, if your ambulance is experiencing any electrical issues, our experienced technicians are here to assist you.