Inter-unit cable diagram and field-wiring terminal board connection

Hazard: Using a screwdriver with a flared tip (instead of a flat tip) to engage a field-wiring terminal-board guide screw.

Consequence: The tip cannot engage the guide, and the screw cannot be tightened.

Avoidance: Use a flat-tip screwdriver for every field-wiring terminal-board screw (TB1/TB2/TB3).

Hazard: Using a screwdriver tip width that does not match the terminal board being worked on — TB1, TB3 and TB2 each specify a different tip width — or leaving the guide insufficiently tightened.

Consequence: There may be burning on the terminal board due to defective contact.

Avoidance: Use the tip width specified for that terminal board (TB1 R,S,T = 3.5 mm; TB3 AC IN, LAMP, DR-SW = 3.0 mm; TB2 R,S,T = 5.5 mm), and fully tighten the guide.

Hazard: Additionally tightening the screw of a cable already connected to the terminal board, while other screws on that same board are loosened for service.

Consequence: If the screws are tightened too much, they may protrude on the inside.

Avoidance: Do not additionally tighten the screws of cables already connected to the terminal board beforehand, while the board's other screws are loosened.