How To Remove Knockouts From Metal Electrical Box

Download Article

A "knock out" or "KO" is a partially stamped opening in electrical enclosures that allows quick entry of a wire, cable or pipe via connector or plumbing fixtures to the interior. With the right information and technique, you should be able to remove a "KO" from electric panels and other electrical enclosures without any bug.

Steps

1

Ensure that the wire/wires yous're going to be dealing with are non powered. Switch off all doubtable breakers and use a suitable meter or tester to ensure that power is off - reducing the chance of shock or burns.^[i]
2

Locate the knock out stamping (KO) sized to fit the desired connector (or fitting). There will probable exist several KOs of dissimilar sizes on more than one surface from which to choose. Option the one that will be easiest to connect the cablevision or pipe.

Advertisement
3

Find the indicate of zipper for this KO. The unmarried size KOs and smallest of multiple KOs are generally secured in a single location. Press the edge of a screwdriver against the inner-well-nigh KO'due south stamped edge, away from this point of zipper, and press (or rap sharply if needed) to button the KO abroad from the wall of the box.
4

Twist the KO back and forth with fingers or pliers to fully remove. The smallest KO is usually a 3/8" or i/ii" trade size opening. Most mod connectors require a minimum 1/2" trade size opening. If this is the size of the KO removed and the connector to be installed, skip head to step ten; otherwise continue to increase to the next stride KO size.
v

Locate the next KO ring point of attachment. The 2d ring of KO is much smaller and may be attached to yet a 3rd (or more) KO band. These KO rings are as well ofttimes secured past two (or more) points of attachment. They will require slightly more try and patience to remove without damaging whatsoever boosted KO rings that are larger than needed. An over-sized opening will not support the connector without additional expense.
half-dozen

Insert the blade of the screwdriver into the opening as shown so that the tip just extends across the opening. The tip should be as far away as possible from the bespeak of attachment. The blade should not extend beyond the the outer border of the inner ring. Gently pry the screwdriver'south tip into the box. Just the inner band of the KO should curve inward.^[2]
7

Echo the previous step in such a way the the tip will press the other portion of the KO band into the box similar as shown.
8

Press the blade confronting the wall, between information technology and KO ring to pry it further inward - enough to take hold of the edge with pliers.
nine

Twist and rock the KO ring back and forth with the pliers only as much equally needed to fatigue the point of attachment. Soon, the KO ring will merely pause away. Excessive strength could impairment any additional KO ring - rendering the opening too large to support the connector.
10

Continue removing KO rings until the correct size opening is achieved.
11

Remove the locknut from the connector.
12

Insert the connector into the opening from the outside of the box.
13

Spin the locknut onto the connector.
fourteen

Concord the connector in identify to go on screws accessible while hand tightening the locknut.
fifteen

Tighten fully by placing the blade of the screwdriver in a "valley" of the locknut, and rap sharply with pliers or hammer.
xvi

Insert the wire, cable or pipe into the connector and secure with screws supplied on the connector body.

Advertising

Add New Question

Question

Why would an electric distribution box be required in additional to the main electrical panel?

Several reasons actually. Hither are just a few: 1. If in that location is not enough circuit chapters in the main box for additional circuits, 2. if circuit breakers listed for apply in the main panel are no longer bachelor, three. information technology costs less (materials and labor) to run a single, big cable to a remote expanse of the property than to bring many smaller cables to the chief console. There are others, but those are the nigh common reasons.
Question

How far should wires be stripped?

Typically about half an inch.

Ask a Question

200 characters left

Include your email accost to go a message when this question is answered.

Submit

Advertizing

Video

"Trade" sizes are very different from "measured" sizes. Electrical trade sizes and plumbing trade sizes are equal, and are based on pipe sizes. An example is ^one⁄_ii inch (1.3 cm) merchandise size; to make up one's mind the actual opening for this size you demand to add 3/8ths of an inch which is seven/8ths of an inch opening. The ⁱⁱⁱ⁄₄ inch (one.9 cm) trade size is a 1 ¹⁄₈ inch (2.9 cm) opening. Similarly, a ^one⁄₂ inch (1.three cm) electrical pipage (EMT, IMC & HW Conduit) or plumbing fixtures and ane/ii plumbing pipe (Galvanized, Black Atomic number 26 and Copper) or plumbing equipment have the same O.D. (outside bore).
A pair of "reducing washers" volition allow a connector to be supported in an over-size opening. Reducing washers are properly sized by determining a.) the size of the existing opening in the box and b.) the size of the fitting. For example, a "ii x one/2" (ii by half) would be selected to install a 1/2" connector into an existing 2 inch hole. Two washer per opening are required.

Thanks for submitting a tip for review!

Advertising

Ever have your time and exist careful.
There may be sharp edges and burrs that may have been left on the edge of the opening, particularly at the signal(s) of attachment of the KO. These sharp edges may be removed with electric pliers. Simply insert the head of the pliers into the hole and twist until has completely confining the opening. The metallic is usually soft enough for the pliers to dull any burrs that may exist nowadays.
Continuity of basis (from pipes and metal jackets of cable) is considered lost for the circuit(south) that enter a knock out that has reducing washers installed. The washers prevent the locknut from biting into the side of the metal box around the the knock out opening. Metal boxes must be grounded; so a ground conductor volition be required at least to be extended into a box to re-institute footing continuity to the box and in the instance of a circuit leaving a grounded box via knock out with reducing washers.
Ever check meters and testers on known live circuits to ensure they work before employ. A lacking tester or meter volition probable bespeak every circuit as "off".^[3]

Things You lot'll Need

Screwdriver
Pliers
Hammer (optional)

About This Article

Cheers to all authors for creating a page that has been read 243,156 times.

Did this commodity assistance yous?