Solution: Panel Builders

Beginning April 25, 2006,  UL508A  will require all Industrial Control Panels to have short circuit current ratings

Highest Rated Devices:

Because the panel builder cannot be expected to know the serving utility's requirements for the actual let through current on a given system, the panel builder will simply over protect the power side of the control system. This will require the component builders to show their materials have been tested to meet a given requirement. In most cases there will be excessive money spent to be sure the control panel is protected.

All devices on the power side (not the control side) of the panel will need to be evaluated starting with something as simple as the power distribution block.

It will be up to the control panel builder to show compliance in the submittal phase of a project. The panel builder should include the SCCR kA for the power distribution block, circuit breaker and starter as a set and plus device on the power side not after the control transformer. The owner and the electrical design engineer should review and compare to the utility supplied actual let through current for the system.