480/277 (4 wire) multi wire circuit?

Status
Not open for further replies.
T

tshephard

Member
I need to wire a series of 277/ 1 phase Fan Coil Units from a 4 wire, Y panel 480/277 w/neutral.
Can I use the same theory as a 240/120 multi wire circuit and reduce the neutral where units meet in a junction box? ie, could three units come together in a jbox, each with a full size hot and neutral, and only send 1 neutral and 3 hots back to panel? I know this is not a good idea for lighting (harmonic currents), but these are strip heat, fan motors, and a transformer for controls only.
When I draw this out, it seems to work. Am I right? Any help appreciated
 
Re: 480/277 (4 wire) multi wire circuit?

I believe you can do this. It would be considered a mulitwire branch circuit (see 210.4).

You may also want to check Articles 424 (Space Heating Equip) and 440 (AC and Refrig Equip) to see if anything there may prohibit what you are doing.

Steve

Edited: Sorry, I now realize you already knew it would be a multiwire circuit from the heading on your post.

[ March 19, 2004, 10:45 AM: Message edited by: steve66 ]
 
Re: 480/277 (4 wire) multi wire circuit?

It seemed as simple as a home (120/240V) MWC when I drew it out, just wanted to make I was not missing something.
Thanks
 
Re: 480/277 (4 wire) multi wire circuit?

Originally posted by tshephard:
Can I use the same theory as a 240/120 multi wire circuit and reduce the neutral where units meet in a junction box?
Click to expand...
I am just wondering what you mean by "reduce the neutral"?

Do you mean reduce the number of neutrals or the size of the neutrals?
 
Re: 480/277 (4 wire) multi wire circuit?

Great. :)

This will be a very cost effective way to power these up and as a bonus voltage drop will be reduced.
 
Re: 480/277 (4 wire) multi wire circuit?

A reduced number of Neutrals (sharing) is permissable. I would suggest that the neutral wires are spliced and do not depend on a device for continuity (Code violation 300.13(B)). And that if the multicircuits terminate on one piece of equipment, that there is simultaneous disconnecting means (210.4,7(C)).
 
Status
Not open for further replies.
Top