To open a hole in a distribution box, remove a "knockout" by carefully pressing, tapping, and twisting it out using a screwdriver or pliers while ensuring the power is off.

Safety First

Before starting, turn off all power to the distribution box and verify with a voltage tester to prevent electric shock or burns ( ). Always wear insulated gloves and safety glasses when working with electrical enclosures.

Identifying the Knockout

A knockout (KO) is a partially stamped circular opening in the box designed for cable or conduit entry. Distribution boxes usually have multiple KOs of different sizes on various surfaces ( ). Choose the KO that matches the connector or conduit you plan to use.

Tools Needed

• Flathead screwdriver or punch
• Pliers (needle-nose or standard)
• Hammer (optional, for tapping)
• Drill with hole saw (for larger custom openings, if necessary) ( )

Step-by-Step Removal

1. Locate the KO: Pick the one that is easiest to access and fits your cable or conduit.
2. Loosen the KO: Place the edge of a screwdriver against the inner edge of the KO, opposite the attachment point. Press firmly or tap lightly with a hammer to loosen it ( ).
3. Twist and Remove: Once loosened, twist the KO back and forth with your fingers or pliers until it detaches completely.
4. Smooth Edges: Check the edges of the opening. If sharp, file or use a grommet to protect wires from damage ( ).

Installing Cables or Conduits

After removing the KO, insert the cable or conduit through the hole. Use glands or grommets to secure and protect the wiring, ensuring a safe and compliant installation ( ).

Tips

• Start with the smallest KO that fits your connector to maintain box integrity.
• For multiple cables, use separate KOs to avoid overcrowding.
• Always double-check that the box is properly mounted and level before wiring ( ). Following these steps ensures a safe and effective way to open a hole in a distribution box for wiring or conduit installation.