On Sat, 27 Mar 2010 16:09:36 -0400, Tom W8JI wrote: >> NO! This is a summary of NEC (National Electric Code) >> requirements: The >> NEUTRAL of a transformer on the secondary side MUST be >> bonded to the >> equipment ground (steel conduit, the green wire, building >> structure, etc), >> and that green wire must be carried from the breaker panel >> to each outlet and >> to the transformer. The neutral conductor that feeds the >> primary side of the >> transformer must be bonded to ground at the service for >> the building (that >> is, the main breaker panel). And, as we all know, all >> groundes must be bonded >> together. Thus, an isolation transformer does NOT isolate >> either the neutral >> or the equipment ground.
>I wonder when that changed? All of my isolation >transformers, probably manufactured in the 70's or 80's, >float the mains terminals on the load side. We used them all >the time working on AC/DC radios and I still use them now >working on SMPS. Only the case and safety grounds are >grounded. I have some UTC or Triads like that too. You can probably get away with using them on a service bench, but an electrical inspector would red tag you if you tried to install them without bonding the neutral. If I'm not mistaken, there also needs to be a breaker or fuse somewhere. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
