Leviton, Multi-Phase Blocking Coupler Data Sheet (.pdf)

• For use up to 225 Amp panel
  
• Compatible with single phase 120/240 VAC, three phase 120/277 VAC
  
• 11/16" diameter cylindrical opening through body of the coupler
  
  Installation Instructions:
  
  
  
• Turn off power at the breaker/panel and test that power is off before wiring.
  
  
• Pass the service's neutral cable through the hole in the body of the blocking coupler, making sure that the arrow on the label points towards the circuit breaker/fuse box. The blocking coupler installs between the circuit breaker panel and the meter socket base or incoming power.
  
  
• Remove 3/4" of insulation from the ends of the circuit conductors (12 AWG) to be used to connect the blocking coupler to the breaker panel. Conductors are user-supplied.
  
  
• Connect the conductors to the blocking coupler, and tighten them under the terminal screws. The neutral (N) screw on the blocking coupler should be connected to a suitable connection point in the circuit breaker/fuse box. Each of the phase terminals (L1, L2, and L3) are connected to dedicated circuit breakers which are connected to the respective phases in the circuit breaker/fuse box. For single phase applications, use the L1 and L2 terminals.
  
  
• Making sure the conductors are securely placed between the terminal clamps, tighten the terminal screws tightly.
  
  
• Secure the blocking coupler to the panel enclosure.
  
  
• Restore power.