Selective coordination

Selective coordination defines a system’s ability to

isolate a fault and increase system reliability. If a

fault was to occur in a selectively coordinated

system (Figure A) the overcurrent protective device

closest to the fault will clear the fault and leave the

rest of the system undisturbed. If the system was

not selectively coordinated, (Figure B) like the

majority of standard RPPs, the breaker closest to

the fault may or may not clear the fault before

upstream breakers start to open causing

unnecessary loss of power to critical loads.

Safety

Working on live electrical equipment is never

recommended, however sometimes becomes a

‘necessary’ task due to the criticality of system

loads in a data center. Cyberex RPPs significantly

enhance worker safety due to its touch safe

panelboard chassis and plug in current limiting

branch breakers. Along with drastically reducing the

shock hazard, the use of current limiting breakers

significantly reduces the arc flash potential to which

a worker could be exposed. Both benefits help users

comply with NPFA 70E guidelines and OSHA standards.