Electrical Box Knockout Sizes

These boxes protect wiring from the elements with gaskets sealed seams and watertight covers.

Electrical box knockout sizes. I plan to install a lot of electrical conduit. First determine the size of the missing knockout hole and subtract 3 8 to figure out what size knockout plug you ll need. Trade size in 1 1 2 57 1 1 4 62 1 2 152 1 93 2 1. 1 2 to 2 157pm.

12 awg is larger than 14 awg so a box can have fewer 12 awg conductors than 14 awg. 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. Knockout non metallic push in connector. Hydraulic with piece maker.

Knockout type conduit size hole range part number page no. It houses a single electrical switch or outlet and comes in metal or nonmetallic units. Knockout holes or knockouts in electrical boxes are made at the factory and have standard sizing to match cable clamps. The 3 4 inch 1 9 cm trade size is a 1 1 8 inch 2 9 cm opening.

Here are the maximum box fill limits for a few common sizes of electrical boxes. 1 2 to 2 170pm. 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 1 2 to 2 159pm.

I have posted the hole saw and knockout sizes for electrical conduit below. An example is 1 2 inch 1 3 cm trade size. 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. 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 179pm. 1 2 to 4 154. A standard rectangular shape is the most common electrical box.

Electrical boxes conduit fittings. For example if you have a 7 8 hole you ll need a 1 2 knockout plug. Standard household circuits are either 15 amp or 20 amp and have 14 gauge 14 awg and 12 gauge 12 awg conductors respectively. Electrical trade sizes and plumbing trade sizes are equal and are based on pipe sizes.

What are the actual hole saw sizes for the various trade sizes of electrical conduit. Notes to the table above.