December 2, 2009 - Eaton announced it is enabling control panel builders to construct control panels that improve safety while preventing application errors. Helping panel builders meet a wider range of short circuit current ratings (SCCR), the newly tested combinations of Eaton’s molded case circuit breakers and power distribution blocks are Underwriters Laboratory (UL) listed for SCCR up to 65 kiloamperes (kA) at 480 volts.
The new high SCCR for power distribution blocks, when used in conjunction with Eaton Series G molded case circuit breakers, offers industrial control panel builders the flexibility of power distribution blocks, along with small size, reset capability, and add-on accessories of circuit breakers, without sacrificing the overall short circuit rating of the panel.Previously, a branch circuit in a UL508A control panel with an unmarked power distribution block was assigned a maximum value of 10 kA. This rating limits the overall SCCR the panelbuilder can achieve. Using tested combinations of Eaton’s molded case circuit breakers and power distribution blocks, the default rating of 10 kA is able to be increased substantially, to as high as 65kA, depending on the breaker and block used.
The new ratings allow for many configurations that make it easier to select the breaker and block to meet the desired short circuit rating for the control panel. Panel builders for industrial control panels, industrial machinery electrical panels and HVAC equipment have several options when distributing power within a control panel through feeder and branch circuit taps:
- Listed and tested power terminal blocks and molded case circuit breakers with high short circuit current ratings
- Multi-wire terminals mounted on the load end of the circuit breaker
- Multi-equipped molded case circuit breaker terminals
