Initial Maintenance of the MCC

Examine the interior and exterior of the MCC for moisture, oil, or other foreign material. Eliminate all foreign material and clean the MCC. Clean the interior and exterior of the MCC with a vacuum cleaner. (Do not use compressed air; it will redistribute contaminants to other surfaces.) Check the enclosure for damage that might reduce electrical clearances. Examine the finish of the enclosure. Touch up the paint if necessary. Replace any corroded or damaged enclosure parts.

DANGER

Hazard of Electric Shock, Explosion, or Arc Flash Apply appropriate personal protective equipment (PPE) and follow safe electrical work practices. See NFPA 70E, NOM-029-STPS, CSA Z462, or local equivalent. This equipment must only be installed and serviced by qualified electrical personnel. Turn off all power supplying this equipment and follow lockout/tagout procedures before working on or inside equipment. Always use a properly rated voltage sensing device at all line and load fuse clips to confirm switch is off. Replace all devices, doors, and covers before turning on power to this equipment. Failure to follow these instructions will result in death or serious injury.

Follow the steps below at the time of installation to locate and tighten any connections that may have loosened during shipment and handling:

1. Turn off all power supplying this equipment before working on or inside the equipment, and follow lockout/tagout procedures. Always use a properly rated voltage sensing device to confirm power is off.

2. Remove the top and bottom horizontal wireway covers in each section.

3. Expose the bus and bus connections by removing the two-piece bus barrier in each section.

4. Examine all bus bars and connectors. Replace any parts that are badly discolored, corroded, pitted, or otherwise damaged.

5. Verify that all bolts at the bus connection points are in place and properly tightened. See Bus Connection Torque Values for torque values.

   Bus Connection Torque Values

   Bolted Connection Location	Torque Range
   Horizontal bus (all locations)	68–70 lb-ft. (92.29–94.54 N•m)
   Horizontal ground bus (all locations)	5–6 lb-ft. (6.75–8.44 N•m)
   Splice bars–0.375 in. diameter bolts	31–32 lb-ft. (41.64–43.33 N•m)
   Splice bars–0.5 in. diameter bolts	68–70 lb-ft. (92.29–94.54 N•m)

6. Access to load-side bus connections for top-feed ArcBlok main sections will be restricted by the cable vault, so an access panel in the cable vault provides access to B phase bus connections. Bus connections for A and C phases are located at the outer edges of the cable vault.

7. Verify that all main lug, circuit breaker, or fusible switch set screws holding incoming conductors in main lugs are in place and properly tightened. Use a torque wrench and appropriate Allen driver to torque the lug set screws to the correct value. Marking inside the MCC units provides tightening torque information.

8. Inspect all insulators, braces, and barriers; replace any that show signs of damage.