Selective coordination is often referred to simply as coordination. Coordination is defined in NEC® 240.2 as: “The proper localization of a fault condition to restrict outages to the equipment affected, accomplished by the choice of selective fault-protective devices.”
A sound electrical enforcement program is an essential element in ensuring safe electrical installations, establishing safe electrical work practices, driving performance requirement compliance, and supporting the installation of emerging technology that uses electrical power.
I have spoken with building department officials who have seen an increase of five to ten times in solar permit applications over the last few years. It is a tough task for them to keep up with the volume with no increase in budget or resources.
This procedure for troubleshooting open-circuit faults in the control circuit is designed to start in the middle of the problem area and give us the best idea of which direction to go. The control transformer is a good place to start since it is in the middle of the circuit and is part of the power and control circuits.