The installation sounds allright to me, Ed. You have disconnect switches (circuit breakers) inside each room and power can be disconnected, in case of an "event", from inside the room where it will be witnessed. Also, when there is no power being drawn through the filters, i.e. when the room is not in use, the only current through the filters is exciting current. I can't see anything wrong with that construction. Perhaps someone else can see something which I have overlooked.
Gabriel Roy (99) Hughes Network Systems, MD The opinions expressed do not reflect those of my employer, who wouldn't be caught dead giving opinions to complete strangers over the net. -------- snip -------------- Ed Price wrote: Hers's the scenario. I have an EMC Lab. In this lab , I have several stand alone rooms within the general parent structure of the building. Each of these rooms is an RF shielded enclosure. Each room is fed with a 60 Hz, 3 phase, 5 wire wye configuration power bus. The source of all of the power feeds is a circuit breaker panel located in a corridor about 100 feet from the lab area. When the breakers in this panel are On, power is applied to each of the shielded enclosure powerline filters and on into the shielded rooms. I then have a distribution panel (inside each room) with breakers, which distribute power to the inside outlets. Now, here's my question. Is there any requirement (US NEC, FM, ordinances, common sense) that there should be a disconnect switch located on the outside of the shielded enclosures? Maybe there's just something that bothers me about leaving power continuously applied to the powerline filters. Sure, I could walk down the hall and flip off the breaker (a politically difficult move opposed by control freak facilities electricians at my plant; "Engineers are too dangerous/stupid to be trusted with access to a circuit breaker"). But I keep thinking that I have heard of some reference that human occupied rooms (sort of sealed, like a photo lab or bio-chamber or a screen room) need a power disconnect immediately outside the access door (maybe so that the power can be chopped off in some conceivable type of emergency). Comments? -------------------------- Name: Ed Price E-mail: [email protected] List-Post: [email protected] Date: 3/15/97 Time: 2:29:25 PM --------------------------
