Protective Device Coordination studies are required to ensure the safety including personnel and general public and to ensure that equipment is not damaged under fault conditions per the requirements of NEC 110-10. Analysis of Time Current Characteristics (TCC) data for the protective devices and equipment (such as transformers and cable) is used to permit the circuit-protective devices to clear a fault without extensive damage to the electrical components of the circuit.
There is a second type of coordination, known as Selective Coordination which uses the TCC curves to ensure that faults (short circuits) affect the least possible portion of the electrical distribution system. Improper selective coordination or no selective coordination can result in faults on branch circuits shutting down complete operations for parts or possibly a whole building, manufacturing facilities. Such undesirable events result in loss of production, loss of business income, inconvenience to customers and risk of injury. These losses can be minimized or completely eliminated by proper Selective Coordination, the second benefit of performing a coordination study.
Correct setting values can only be determined by a study based on all the pertinent electrical characteristics of the equipment in the system.
Suggested Coordination Studies and Related Services: