Peter, I do not have specifics, so I can only offer general information. The use of external breakers is acceptable for testing and certifying products that are hardwired to the electrical distribution of a facility for when fault current or withstand testing is required. In the US, the UL standards typically denote the overall requirements of the test and pass/fail criteria. The NEC may also detail specific information about over-current protection for specific devices. When an external breaker is utilized, it is required to be denoted in the installation instructions (UL requirement). However, this does present some issues when installed as the product may be preceded with a breaker that is different than what was tested. Remember, not all breakers are created equal. Therefore, testing of fault currents with one breaker may yield one result and testing of another manufacturer's breaker may have a second result. When products are cord connected, one is usually required to have internal over-current protection. However, I believe that this is a general guideline not a stead fast rule. Thanks,
Bryan Cole Director of Engineering Product Safety Officer Emerson Network Power - Control Concepts Binghamton, New York 13902 Phone: 607.724.1352 extension 238 Fax: 607.724.0153 E-mail: [email protected] www.Liebert.com www.Control-Concepts.com www.Edcosurge.com From: peter merguerian [mailto:[email protected]] Sent: Tuesday, January 28, 2003 2:54 PM To: [email protected] Subject: Circuit Breaker Tripping Dring Fault Tests Dear All, For safety, it is not clear from the standards whether the main branch circuit breaker tripping during fault conditions is an acceptable result. I see no reason why this should not be acceptable. What is your view? Some third party labs find it acceptable and others do not. Anyone can lead me to some inernational decisions regarding this issue? Thanks, Peter _____ Do you Yahoo!? Yahoo! Mail <http://rd.yahoo.com/mail/mailsig/*http://mailplus.yahoo.com> Plus - Powerful. Affordable. Sign up < ttp://rd.yahoo.com/mail/mailsig/*http://mailplus.yahoo.com> now The information in this electronic message may be privileged and confidential and is intended for the use of the individual(s) named above. If you are not the intended recipient, you are on notice that any unauthorized disclosure, copying, distribution, or taking of any action in reliance on the contents of these electronically transmitted materials is prohibited.
