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#101889 01/05/04 07:21 PM
Joined: Oct 2003
Posts: 31
C
Clyde Offline OP
Member
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.....

Thanks

#101890 01/07/04 12:55 AM
Joined: Oct 2003
Posts: 147
C
Member
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).

#101891 01/07/04 03:34 PM
Joined: Oct 2003
Posts: 172
G
Member
why not just go 600v lighting?

#101892 01/07/04 10:46 PM
Joined: Oct 2003
Posts: 31
C
Clyde Offline OP
Member
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.

#101893 01/08/04 01:10 AM
Joined: Apr 2002
Posts: 2,527
B
Moderator
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]

The arrangement for operating 277V lighting on a 480V ungrounded service is described in: www.ecmweb.com/ar/electric_unconventional_transformer_connections In this case, three 1½KVA transfomers permitted 18.75A/ø.

Clyde — What is the namplate current on the sixty 347V fixtures?

[If you like, I can post a typical interconnection diagram when the local server is back up.]

#101894 01/08/04 06:57 AM
Joined: Oct 2003
Posts: 31
C
Clyde Offline OP
Member
The name plate currant is 1.2 amps.

#101895 01/08/04 10:57 AM
Joined: Oct 2003
Posts: 172
G
Member
just curious but if you open up the cover to these fixtures they might be a multi tap ballast,or you might want to ask manufacturer if they can be changed to 6oov,easily.

#101896 01/12/04 04:36 PM
Joined: Apr 2002
Posts: 2,527
B
Moderator
 
[Linked Image from 6l6.net]
 

#101897 01/12/04 04:54 PM
Joined: Apr 2002
Posts: 2,527
B
Moderator
Looks like 24 amperes/ø. So, that would translate to a set of 2kVA 240x480–120/240V drytypes, or 120x240—120/240V units, with appropriate connection changes in the diagram.

Note that in NFPA territory, the arrangement is permitted by 99NEC450-5, with attention paid to the overcurrent-device location in the circuit.

#101898 01/13/04 02:35 AM
Joined: Sep 2003
Posts: 200
U
Member
Maybe its worth inquiring to see if the power authority can upgrade the service to include a neutral?

(I haven't a clue what the transformer solution is worth.)

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