I'm going to stick my neck out here and say from two experiences with this topic, there's a couple of things to consider ...
First, ideally, any potential difference between GROUNDS should be zero. If you had asked about NEUTRALS, I'd have to say - unknown. The physical connection is a function of the connection to the transformer by the electricians and imperfections in the transformer. Second, it's a function of what's sourcing the difference. I worked at a place where the outlets in one half of the lab were supplied by a different substation than the outlets at the other end of the lab. Without knowing the issue, we connected two different machines with a coax. Each machine eventually connected to different substations by way of differently sourced outlets. And we watched with amazement as the rubber jacket of the coax melted. All with a 15V difference. The electricians were notified and the problem was solved but a potential difference of some sort was still there. I don't think you'll ever get away from it. So, I guess what I'm saying is that you should not only consider the voltage difference, but the power involved. And that would be have to tested some other way. - Doug McKean Kelly Tsudama wrote: > > Hi gang! > > I have been asked to look into ground potential differences by one of the > teams that I support. Can any of you provide any insight on how I can > determine the maximum potential difference between different ground circuits > within a building??? I've heard numbers ranging from 2V to 50V!!! Even with > all the bonding requirements in the NEC, there must be some voltage > differential between grounding points??? > > Thanks for any help you can provide. > > Kelly ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org