Performance Comparison of ZMAC engineered switches

The following table was created to illustrate the ZMAC switch performance that would be expected when installed in a demanding application.  In most cases the incident energy will be lower than what is shown here due to the additional cable lengthes that would typically exist.  More cable length will lessen the available fault current to feed into a short circuit.  

This table brings attention to the fact that some products have faster fault clear times (FCT) than others and this is significant.  A fault clear time of 3 cycles (50mS) or less is highly desirable in remediation work.  

Fuses are not used in our products because they are not resettable, not shunt tripable, and not adjustable.  Even though fuses can open faster than circuit breakers more often than not there is not enough current available to operate a fuse quickly.  A circuit breaker can be adjusted to open quickly throughout a broad range of applications. 

Test parameters: 1500 kVA transformer delta/wye solidly grounded with 6% impedance, 50 feet of 480 volt bus to distribution equipment, 50 feet of cable to the ZMAC switch, 50 feet of cable to the equipment being remediated. Analysis completed in SKM Version Actual conditions and results will vary but the data shown in this table can be characterized as typical. 

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