Cisco UC540W-BRI-K9 - Uc System With 2BRI 1VIC Exp Quick Start Manual page 13

Crimp the ground wire to the ground lug or ring terminal, using a
S 2
TEP
crimp tool of the appropriate size.
Attach the ground lug or ring terminal to the chassis. Tighten the
S 3
TEP
screws to a torque of 8-10 in-lb. (0.9-1. 1 N-m).
Connect the other end of the ground wire to a known reliable earth
S 4
TEP
ground point. If there is any doubt as to the reliability of the ground
point, contact a licensed electrician for assistance.
12 Cisco Unified Communications 500 Series Model UC 540 Quick Start Guide
Ground Lug