I have a qustion someone might be able to help me with. A farmer asked me today if he could install 60 347 volt lights. He does not have a neutral on his primary service going into his building. Can this be accomplished without the use of transformer to provide a neutral to install these lights.....
Clyde: When you mention service neutral, are you talking about a service or are you talking about a feeder. A service has to have a neutral, see 4-022 (3). If it is a 600V feeder, 347V can (in theory) be obtained by a wye connection, but this is not acceptable to code. The star point is a neutral and has to be grounded at the service, 10-106 (1),(b) and 10-204 (1),(a).
The problem is this farmer is pretty cheap. He was given the 347 volt light fixtures and is not really interested in spending any money. The service is quite old and is only a three wire, 600 volt. 400 amp. I did a little research and the only thing I can find is that he needs a transformer at least 25kva. Something about doing mostly control work, you don't get a whole lot of experience with this sort of thing. Thanks for your help.
If Canadian Codes permit and the building service is ungrounded 600V 3-wire, it may be possible to assemble a zig-zag grounding autotransformer to provide a neutral for the 347V fixtures. Three drytype transformers rated 240 x 480 Volts–120/240 Volts would be OK for up to 360V ø-n. [Alternate rating 120 x 240 Volts – 120/240 Volts]