How to Turn OFF Main Power Supply

Before starting any work, you must disconnect the circuit you’ll be working on at its source in the service panel. If your  circuits are protected by fuses, removing the appropriate fuse  disconnects the circuit from incoming service. In a service panel equipped with circuit breakers, you can disconnect a circuit by switching its breaker to the OFF position.


Color Coding of Wires and Terminal Screws


To make sure you disconnect the correct circuit, turn on a light that’s connected to the circuit before you remove the fuse or turn off the circuit breaker. The light will go out when you’ve removed the correct fuse or turned off the correct breaker. If you have any doubt about which fuse or breaker protects which circuit, shut off all current coming into your home at the main disconnect

circuit breaker

While you’re at your service panel, spend another  moment to prevent a possible disaster. Tape a note on the panel explaining what you’re doing so no one  will come along and replace the fuse or reset the circuit breaker while you’re working on the wiring.Then either carry the fuse with you in your pocket or tape the circuit breaker in its OFF position.

With the electricity turned off, you can work in complete safety. Still, it’s a good idea to keep a few additional safety precautions in mind.

Remember that water and electricity don’t mix. Never work on wiring, fixtures, switches, or appliances when you’re wet or  standing on a damp  spot. Lay down dry boards to stand on if the floor or ground is wet.

Lever disconnect

An external handle controls contact with two main fuses in the cabinet. When you pull the handle to the OFF position, you shut off the main power supply.


lever disconnects



Pull-out block

The main cartridge fuses are mounted on one or two nonmetallic pullout blocks. By pulling firmly on the hand grips, you can remove the blocks from the cabinet and disconnect all power.

pull out block


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