The Sterling Automatic AC Crossover Switch is a three-stage sequential switch which will automatically switch the AC power sources on board. It will ensure that only one AC power source will be on your vehicles ring mains at any one time, thereby protecting your electrical equipment from possible damage.

The complexity of the system is masked by its easy installation and fully automatic operation. Basically, the unit is a three-stage sequential switch with the channel marked “shore power” as the priority selection. The channel marked “generator” is second, and the channel marked “inverter” is third. This default setting works on the assumption that the boat has shore power, a generator and an inverter. However, some vehicles may have 2 generators and no inverters, in which case you can simply use the inverter port as another generator port etc. In fact, you can mix and match as you wish. There are a few things which are unique to each channel but these do not affect the channels from being used for an input source other than the default.

It is important to stress that this system operates by itself in fully automatic mode and requires no human intervention. However, for more complicated systems, the Sterling Automatic AC Crossover Switch offers many additional and sophisticated features.

Includes remote control.

• 3 input 32 amp 110/230V a/c auto selector with remote control
• Generator: up to 8000 Watt continuous 32 amp 230 volt a/c, fused, or other source
• Inverter: up to 8000 Watt continuous 32 amp 230 volt a/c, fused or other source
• Shore Supply: up to 8000 Watt continuous 32 amp 230 volt a/c, fused, or other source
• Boat/vehicle electrics: the new simple power selector offers many new features not available on the older 16amp crossover switch, due to its digital control system.
• 40 amp internal contactors: switches live and neutral with a 0.25 sec time delay between switch off and on to prevent wave doubling of the voltage and destroying sensitive equipment.
• Multiple internal power sources: the system powers itself from each attached power supply; and not from the boats/vehicles D/C system. This is to ensure the system will work even if your batteries are flat. There is no point having an a/c selector switch powered from the D/C system, because if the D/C system fails then you cannot switch the system on to charge the batteries. The Sterling system obtains its control power from each input source, so preventing this problem.
• Sequential switching: the unit has a simple operation mode; channel 1 is the priority, then channel 2, then 3. In other words if you allocate the inverter to channel 3 then plug in the shore power on channel 1, the switch will automatically switch the system to the shore power etc.
• Lock out circuit: it is assumed that channel 3 would be your inverter (it could be another power supply depending on how you wire the system up). With a lower power inverter you may not wish your immersion heater or battery charger to work when the inverter is on line; so connected to this circuit is a small relay which can break the control circuit on an external contactor /relay block. This then allows you to wire the battery charger and immersion heater to a separate contactor block, preventing these items being on line when the inverter is operational.
• Remote control: the remote control will tell you which circuit is the current power circuit; and if the light is flashing, then it will also show if power is available on another circuit. There is also a fault light.
• Faults / Reverse polarity check: the unit will show if there is a reverse polarity on channel ‘A’ which is assumed to be the shore supply system.
• Internal fuses: the control box has 6 internal fuses; one on each live and neutral, so that even in the event of a reverse polarity the neutral line is also fused for safety reasons.
• Remote on/off: this switch enables the shore power to be switched off (the priority circuit) in the event of the shore power not being powerful enough to do a specific job, for example if your shore power was limited to say 5 amps (about 1.2 kW) but your immersion heater/washing machine may be 3000 watt, you may wish to shut down the shore supply and allow the more powerful inverter or an onboard generator to do the job.
• 230 v or 110 volt: or a mixture of each can be used at the same time, ensuring operation in all the world’s different power supply conditions.
• Other features: includes a 10 second time delay on the generator line to allow generator start up.

Technical information

Further information

• Download ProSwitch instructions