Figure 2-16. Circuit breaker installation

(14)

After completing the fifth racking

(5) Slowly lower the breaker onto the tray

stroke, lift the handle as high as it will go and allow it

guiding it so that the holes in the rear angle of the breaker

to drop to its normal position. This operation will

fit over the two dowel pins on the tray. If the breaker is

reverse the pawl so that it is set for a racking out

correctly positioned on the dowels, its rear and side

operation.

bottom frame angles will all sit firmly on the tray.

(6) Insert two 3/ 8 inch hex head bolts

CAUTION

through the holes in the front of the side angles of the

Any stroke beyond this point will cause the

breaker base. Thread them part way into the tapped

breaker to be trip-free.

holes in the tray. Do not tighten the bolts firmly. ''his will

permit self-alignment of the primary disconnects during

(15) Tighten the 3/8 inch hex head bolts inserted

the subsequent racking operation.

in the front holes of the drawout tray. The breaker is now

(7) Remove lifting device and sling.

aligned and in the "Connected" position.

(8) Push the breaker into the compartment until

the Lest position stop engages preventing further travel.

(9) Release the test position stop by depressing

its lever and push the breaker back into the compartment.

The racking pins on the compartment housing should butt

against the outer surface of the racking cams of the

breaker.

(10) Lift racking handle as high as it will go. This

engages pawl to first notch on the cam.

(11) After pawl engages the first notch on the

cam push handle down to its normal position. This

causes the cam to rotate about the racking pin.

(12) Repeat steps (10) and (5) five times to rack

the breaker into its final "Connected" position. Interlocks

hold the breaker trip-free until it is racked into the fully

"Connected" position.

NOTE

It is imperative that each stroke is performed

with a positive motion and carried to its limiting

position. Once a racking operation has been

started it should be completed. as the breaker

cannot be reversed until the racking operation is

completed.

(13) The fifth stroke of the handle is only a partial

stroke and does not result in any further movement of the

breaker.

NOTE

The fifth stroke serves three useful purposes: I-It

positions the cam so that it cannot rotate and allow

the breaker to back out under short circuit stresses.

2- 'The partial stroke signals that the racking

operation is complete. 3-It releases the trip interlock

Figure 2-16. Circuit breaker installation.

which was engaged by' the racking pin during the

previous four pumps of the racking handle.

2-17