External disconnect enclosure for NFPA-70E compliance

By Plant Engineering Staff November 8, 2006

SEQUESTR external disconnect enclosure is designed to help manufacturers comply with NFPA-70E and other regulations. It isolates the fused disconnect switch or circuit breaker from the main control panel while maintaining the door interlocking requirements of NFPA-79, IEC-60204 and SAE HS1738.

With traditional disconnect enclosures, even when power is turned off, live power is still present on the line side of the switch, requiring anyone accessing the inside of the enclosure to wear PPE appropriate for the amount of potential incident energy present. Wearing bulky PPE while servicing electrical equipment decreases productivity by increasing service time. By isolating the switch, live power is no longer present in the main control enclosure when power is turned off at the switch. When the main power is on at the disconnect, SEQUESTR’s own door cannot be opened, and its interlock prevents the main control enclosure door from being opened.

The enclosure is available as a complete package for OEMs building new systems and as a retrofit kit for upgrading existing installations. It meets UL-508A, UL-508, UL Type 12, NEMA/EEMAC Type 12, JIC standards EGP-1-1967 and EMP-1-1967, CSA-C22.2 No. 94 Type 12 and IEC 60529 IP55.