Safety Considerations
62 7750 SR-a4 and SR-a8 Installation Guide
Grounding
The router is suitable for installation as part of the Common Bonding Network (CBN) or an 
Isolated Bonding Network (IBN).
The router is suitable for installation in Network Telecommunication Facilities or locations 
where the NEC applies.
Danger: AC powered units
• Chassis ground cables are not included. Use only power cords that have a grounding 
(earthing) path. Main grounding (earthing) connection points are through the IEC60320 
appliance inlets. Grounding (earthing) points on the sides of the equipment are for 
equipotential bonding only and are safety grounding (earthing) points for the equipment. 
Lack of correct grounding (earthing) of the equipment may result in a safety hazard and 
excessive electromagnetic emissions. 
The ground conductor must be #8 AWG minimum or the same AWG as the power 
conductors if they are larger.
• The router and equipment rack must be correctly grounded. If you ground the 
equipment by a method other than those provided in this manual, that method should 
be in compliance with all local wiring regulations and practices.
Warning: 
• Electrostatic discharge (ESD) damage can occur if components are mishandled. 
Always wear an ESD-preventive wrist or ankle strap in contact with bare skin. Always 
connect the ESD strap (with banana plug) to the ESD connection socket (grounding 
jack) on the front of the chassis. An ESD strap is included in the accessory box that is 
shipped with the chassis.
Danger: DC powered units
• The 7750 SR-a includes a terminal for chassis ground on the front of the chassis. For 
both AC- and DC-powered deployments, the ground terminal must be connected. 
Ensure that all power is OFF from the DC circuit. Locate the circuit breaker on the panel 
board that serves the DC circuit. Switch the circuit breaker to the OFF position. For extra 
safety, you can tape the handle of the circuit breaker to the OFF position.
• When wiring the unit, the ground connection must always be made first and 
disconnected last.
• The correct wiring sequence is -V BAT/negative to -V BAT/negative and 0V 
RTN/positive to 0V RTN/positive.