The Main Power Circuit Breaker is Tripping{1420} Caterpillar

Wheel Loader:

966H (S/N: A6D1-1302)

972H (S/N: A7D1-556)

950H (S/N: M1G1-1030; K5K1-1639)

962H (S/N: M3G1-328; K6K1-322)

Integrated Toolcarrier:

IT62H (S/N: M5G1-433)

Introduction

The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.

Problem

The Main Power circuit breaker trips in the following panels.

• 291-8387 Circuit Breaker Panel Gp

• 237-4905 Chassis Wiring Gp

Illustration 1	g01424824
A close up view of an incorrectly configured Circuit Breaker Panel Gp is shown. (1) 50 amp Main Power circuit breaker (2) 80 amp Starter Relay circuit breaker

This may be due to incorrect placement of the Main Power circuit breaker and the Starter Relay circuit breaker. If the circuit breakers correspond to Illustration 1, then proceed with these instructions.

Solution

The following tools are required for this procedure:

• Nm Torque Wrenches (lb ft and lb in)

• 10 mm Socket

• 7/16 inch Socket

• 3 mm Allen Wrench

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Illustration 2	g01424798
The interior of a typical Circuit Breaker Panel Gp is shown. (3) Bolts (4) Main Power relay (5) Starter relay

1. Remove the three bolts (3) that are holding the Main Power relay (4) and the Starter relay (5) in place. Use a 10 mm socket wrench.

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Illustration 3	g01424802
The interior of a 291-8387 Circuit Breaker Panel Gp is shown. (6) Nuts (7) Washers (8) Bus bar (9) Power leads

2. Remove the nuts (6) and the washers (7) that are holding the bus bar (8) and the relays in place. Use a 7/16 inch socket wrench.

   Note: The 291-8387 Circuit Breaker Panel Gp uses six nuts and washers. All other panels use five nuts and washers.

3. Note the location of the two Power leads (9). Create a drawing of the locations or else mark the leads.

4. Remove the power leads (9) and the bus bar (8). Refer to Illustration 3.

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Illustration 4	g01424829
A close up view of the relays is shown. The bus bar has been removed. (10) Lock washers

5. Remove the lock washers (10) from the studs of the circuit breakers.

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Illustration 5	g01424833
The interior of a typical Circuit Breaker Panel Gp is shown. The relays have been moved in order to access the circuit breakers. (1) (2) . (1) Main Power circuit breaker (2) Starter relay circuit breaker (4) Main Power relay (5) Starter relay

6. Move the relays in order to access the circuit breakers.

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Illustration 6	g01424841
The front panel of a typical Circuit Breaker Panel Gp is shown. Note that this panel has incorrectly installed circuit breakers. (1) Main Power circuit breaker (2) Starter relay circuit breaker (11) Allen head screws

7. From the front of the panel, remove the four Allen head screws (11) that secure the circuit breakers in place. Use a 3 mm Allen wrench.

8. Relocate the circuit breakers to the correct locations. Refer to Illustration 7.

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Illustration 7	g01424790
A close up view of the correctly configured Circuit Breaker Panel Gp is shown. (1) 80 amp Main Power circuit breaker (2) 50 amp Starter relay circuit breaker

9. Install the Allen head screws (11) that were removed in Step 7. Tighten the screws hand tight. Use a 3 mm Allen wrench. This action secures the circuit breakers in the panel. Refer to Illustration 6.

10. Install the lock washers (10) that were removed in Step 5 on the studs of the circuit breakers. Refer to Illustration 4.

11. Install the relays in the panel. Use the bolts (3) that were removed in Step 1. Use a 10 mm socket wrench. Torque the bolts to 12 ± 3 N·m (9 ± 2 lb ft). Refer to Illustration 2.

12. Install the bus bar. Refer to Illustration 3.

13. Install the two power leads. Refer to Illustration 3.

14. Install the washers (7) and nuts (6) that were removed in Step 2 onto the studs of the circuit breakers. Use a 7/16 inch socket wrench. Torque the bolts to 7 ± 1 N·m (62 ± 9 lb in). Refer to Illustration 3.