Electrical Box Knockout Sizes

To determine the actual opening for this size you need to add 3 8ths of an inch which is 7 8ths of an inch opening.

Electrical box knockout sizes.

1 2 to 2 152. 1 2 to 2 170pm. Knockout type conduit size hole range part number page no. The national electrical code article 314 contains complete details and tables of electrical box sizes in dimensions and cubic inches and should be consulted for complete accuracy because the actual size of the box required in cubic inches depends on the number of wires that will be within that enclosure.

1 2 to 4 154. Trade size in 1 1 2 57 1 1 4 62 1 2 152 1 93 2 1. Knockout non metallic push in connector. It houses a single electrical switch or outlet and comes in metal or nonmetallic units.

The 3 4 inch 1 9 cm trade size is a 1 1 8 inch 2 9 cm opening. For example if you have a 7 8 hole you ll need a 1 2 knockout plug. Here are the maximum box fill limits for a few common sizes of electrical boxes. I have posted the hole saw and knockout sizes for electrical conduit below.

What are the actual hole saw sizes for the various trade sizes of electrical conduit. I plan to install a lot of electrical conduit. 1 2 to 1 1 4 158pm. Notes to the table above.

1 1 2 to 2 159pm. Knockout holes or knockouts in electrical boxes are made at the factory and have standard sizing to match cable clamps. 12 awg is larger than 14 awg so a box can have fewer 12 awg conductors than 14 awg. But sometimes the standard knockout openings in a wall box aren t large enough for the cable clamp or conduit fitting you need to attach to the box so you have to enlarge the hole.

1 2 to 2 179pm. Electrical trade sizes and plumbing trade sizes are equal and are based on pipe sizes. First determine the size of the missing knockout hole and subtract 3 8 to figure out what size knockout plug you ll need. Hydraulic punch driver straight 90 deg.

These boxes protect wiring from the elements with gaskets sealed seams and watertight covers. Different electrical box sizes fit varying installation needs. I know that i will need to drill with hole saws or use a knockout punch in junction boxes and the circuit breaker panel. 1 2 to 2 157pm.

A standard rectangular shape is the most common electrical box. An example is 1 2 inch 1 3 cm trade size.