Karl H
Senior Member
- Location
- San Diego,CA
I've been a service commercial/industrial electrician for 21 years now. I've had a problem that has confused me since I was a 2nd year apprentice. As everyone knows, there are 5 types of electricians; those that don't know, those that don't care, those that don't know and don't care but only want a paycheck, those that don't know but can make-up logical fairy tales on the spot and finally, those that know but who we never seem to encounter when it comes to the NEC or electrical theory. Of all of these types...I've come across the entire lot, except of course, the ones who are truly educated. Ponder the following situation; you have a single phase 3 wire ckt, A and B phase are under load, the grounded conductor is carrying the un balanced current and someone before you didn't follow ART 300-13 "Device Removal"... you open a J-box, the solderless pressure connector "pops-off" (in search of freedom no doubt), the customers new 120v 16I machine gets force fed 208v, followed by the facility manager frantically asking, "What did you do??????" You answer, "Open a J- Box!!!!!!" The above actually happened to me in 1986 and ever since then, I've been wondering how one of the phases can double its voltage in an open grounded conductor scenario? I can recreate it "safely" with two keyless fixtures; one with a 60watt bulb and one with a 150 watt bulb, two separate ckts sharing one common grounded conductor, with a switch to open the grounded conductor. Can someone please explain to me, how does this elevation in voltage occur? I hope someone out there can explain this to me without telling me "in an open neutral...electron fairies get their wings!!!!!!" lol