On Wednesday, May 30, 2012 11:55:38 PM Jon Elson did opine: > fritz wrote: > > As an electrician, I should now interject that a neutral should only > > be bonded at the point of distribution (the breaker panel or upstream > > transformer). Grounding a neutral anywhere else makes for strange > > problems and stray currents on the ground. People often falsely > > assume electricity takes the path of least resistance - according to > > Ohm's law, it follows ALL paths in a parallel circuit. > > But, in the special case of shifting the neutral from what is > effectively a center grounded > open delta to a 4-wire Wye service via an isolating transformer, you > have to ground > the center of the isolated Wye at the secondary of the isolating > transformer. > > Jon > Actually, earth grounding it at the machine is probably is a bad idea, however continuity to the house neutral is how I would do it, with a single strand of 4 gage back to the neutral in the service entrance, in that manner preserving the star topology of a good grounding system. Ack the NEC, there should be a pair of ground rods driven at least 6 feet apart, more or less under the meter head and bonded to the neutral in the service entrance, with not less than 8 gage solid copper conductors down to the rods, one per rod.
Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> Coward, n.: One who in a perilous emergency thinks with his legs. -- Ambrose Bierce, "The Devil's Dictionary" ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
