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eBook Item #4

Master On/Off Switch

Product Description:

  • Single circuit on/off switch
  • Continuous rating: 300A
  • Voltage range: 12-48V
  • Colors: Red or black


Frequently Bought Together

Below are the most commonly used components when installing this master switch.

  • 2/0 AWG Wire – This wire connects the switch to the batteries and to the bus bars. Learn more about this wire.
  • 3/8″ Copper Lug – Crimps onto the  2/0 AWG wire and attaches to the switch.
  • Bus Bar – The switch connects to this bus bar so that power is distributed to downstream electrical devices. Learn more about bus bars.
  • 300A ANL Fuse – The switch connects to the 300A fuse to protect the electrical system.

Where To Install The Master Switch

This master on/off switch is installed between the 300A fuse and the positive bus bar (red). To make the connection, use 2/0 AWG wire and 3/8″ copper lug terminals. Refer to the wiring diagram below to visualize where the switch is installed.

Connecting batteries to bus bars for a 12v system build

Need More Wiring Information? Download our Electrical Wiring eBook.

Technical Details

Switch Positions


Current Rating

900A Cranking (30 sec)/ 500A Intermittent (5 min)/ 300A Continuous

Max Voltage

48V DC

Terminal Stud Diameter

3/8" (M10)

Standards Met

IP66 waterproof, ISO 8846 and meets ABYC requirements.

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