I am working on the mass transit project which has NFPA 130 (2003 edition) and NEC (2002 edition) as part of it's requirement.
Section 5.4.7 of the 2003 edition of NFPA 130 reads as follows:
5.4.7: Overcurrent elements that are designed to protect conductors serving emergency equipment motors (pumps, etc.), emergency lighting, and communications equipment that are located in spaces other than the main electrical distribution system equipment rooms shall not depend on thermal properties for operation.
The nature of mass transit projects will locate some electrical panelboards outside of the main distribution room (AC switchboard room). These are standard panelboards with molded case CBs. Most of the CBs will be thermal magnetic type. However, some loads as listed above in NFPA-130 5.4.7 will be fed via instantaneous trip circuit breaker (magnetic-only CBs).
Going through the NEC, I noticed that article 430-52-(c)-3 states:
430-52-(C) (3): An instantaneous trip circuit breaker shall be used only if adjustable and if part of a listed combination motor controller having coordinated motor overload and short-circuit and ground fault protection in each conductor, and the setting is adjusted to no more than the values specified in table 430-52.:huh:
Furthermore, I can not find anything in the NEC dealing with instantaneous trip circuit breaker for non motor application like emergency lighting and communication equipment. Are they allowed for such loads?:blink:
Also, do you guys know if magnetic-only CBs can fit into a standard panelboards (plug on, bolt-on)?:?
Section 5.4.7 of the 2003 edition of NFPA 130 reads as follows:
5.4.7: Overcurrent elements that are designed to protect conductors serving emergency equipment motors (pumps, etc.), emergency lighting, and communications equipment that are located in spaces other than the main electrical distribution system equipment rooms shall not depend on thermal properties for operation.
The nature of mass transit projects will locate some electrical panelboards outside of the main distribution room (AC switchboard room). These are standard panelboards with molded case CBs. Most of the CBs will be thermal magnetic type. However, some loads as listed above in NFPA-130 5.4.7 will be fed via instantaneous trip circuit breaker (magnetic-only CBs).
Going through the NEC, I noticed that article 430-52-(c)-3 states:
430-52-(C) (3): An instantaneous trip circuit breaker shall be used only if adjustable and if part of a listed combination motor controller having coordinated motor overload and short-circuit and ground fault protection in each conductor, and the setting is adjusted to no more than the values specified in table 430-52.:huh:
Furthermore, I can not find anything in the NEC dealing with instantaneous trip circuit breaker for non motor application like emergency lighting and communication equipment. Are they allowed for such loads?:blink:
Also, do you guys know if magnetic-only CBs can fit into a standard panelboards (plug on, bolt-on)?:?