Balancing PDU’s: The typical colocation cabinet is often equipped with dual power feeds and
dual PDU’s referred to as A and B circuits. Having two PDU’s allows for support of dual corded
equipment within the cabinet – this type of equipment uses two power supplies for redundancy, in the
event one power supply or the circuit supplying it fails, the other will automatically assume the full
demand of the equipment. Under normal operation both supplies evenly share in their power
demands – this makes managing power loading at the PDU level critical in order to maintain
operating redundancy. In practice, to maintain PDU redundancy you should not exceed 40% of the
circuit’s rated ampacity supplying either A or B PDU. Exceeding this value will result in an “A” circuit
tripping its breaker if a “B” circuit fails because all load will be transferred to the redundant power
supplies being fed by the “A” circuit. This doubles the demand on the remaining PDU and trips its
breaker.
Available space in a colocation cabinet does not necessarily mean available resources
dual PDU’s referred to as A and B circuits. Having two PDU’s allows for support of dual corded
equipment within the cabinet – this type of equipment uses two power supplies for redundancy, in the
event one power supply or the circuit supplying it fails, the other will automatically assume the full
demand of the equipment. Under normal operation both supplies evenly share in their power
demands – this makes managing power loading at the PDU level critical in order to maintain
operating redundancy. In practice, to maintain PDU redundancy you should not exceed 40% of the
circuit’s rated ampacity supplying either A or B PDU. Exceeding this value will result in an “A” circuit
tripping its breaker if a “B” circuit fails because all load will be transferred to the redundant power
supplies being fed by the “A” circuit. This doubles the demand on the remaining PDU and trips its
breaker.
Available space in a colocation cabinet does not necessarily mean available resources
