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Center of Excellence

The dedicated Masterpact Resource Site of Leading UK switchgear experts PS Electrical

24/7 Emergency Call

We operate a 24/7 emergency call out service in support of air circuit breakers. If you're experiencing problems please call us directly

+44 (0) 1299 251 758

Trip Unit Times


  • Trip-Units Times Issue #1 

    Issue #01 DEC.2014 UL & CE Certification The Amp Safe Pro™ is now UL and CE listed for use in Masterpact M Series Breakers! PS Electrical Services are very excited to offer a UL and CE listed solution for the Square D and Merlin Gerin Masterpact STR trip units. The testing was performed to the ANSI/IEEE C37.59 standard for UL certification. The breaker and Amp Safe trip unit were tested by interrupting two consecutive 65,0000 amp faults at 635 volt 3-phase. With the completion of this test, Amp Safe now is the only UL and CE listed option for the Masterpact M series breakers. Schneider Electric released a video outlining the known issue of low current nuisance tripping with the STR units. (video now removed from Schneider website) This link will take you to the Schneider video, the STR's are mentioned around the 1:30 minute mark. In order to provide… Read more…