Eaton Power Circuit Breaker MDS-H12

Verify device (Fixed) position of poles is open

Verify device (Fixed) mechanism is discharged

Verify device (Fixed) position in cassette is empty

Verify device (Drawout) position of poles is open

Verify device (Drawout) mechanism is discharged

Verify device (Drawout) position in cassette is removed

For Magnum Breakers with Vertically Mounted Primary Disconnects

Verify vertical adapter nuts and bolts are torqued to 37–43 lb-ft

Ensure the following conditions for Fixed Device

Ensure the following conditions for Drawout Device

Remove the drawout circuit breakers from the cassette

Remove all primary and secondary power for fixed mounted circuit breakers

Verify breaker operation by charging, closing, recharging, and opening the breaker

Verify that the breaker secondary disconnect pins are fully seated and locked into position by lightly pulling on each wire individually

Ensure all pins are straight without bends, corrosion, or evidence of arcing

Use the mating line of the housing halves as a reference guide for visual inspection

Remove the arc chutes and inspect each primary contact structure for signs of wear and/or damage

Use the contact wear indicator to inspect each contact

Is the back end of any contact below the ledge?

Replace the contact assembly if any contact is below the ledge

Charge the breaker mechanism springs

Press the ON pushbutton to close the breaker manually

Verify closing by noting the state of the indicating flag (Figure 93)

Charge the breaker mechanism springs again

Disconnect power to the motor operator to prevent automatic recharging

Press the OFF pushbutton to manually open the breaker

Press the ON pushbutton to manually close the breaker