quadraplex for a 3 phase branch circuit

[augie47]

OP: Does the pole disconnect have over-current protection or is it NF ??

 

[wmthompson90]

OP: Does the pole disconnect have over-current protection or is it NF ??

it is fused.

 

[augie47]

it is fused.

Then anything downstream from that disconnect would be a feeder and an EGC would be required and your bare conductor would be that EGC and should not be used as a neutral.

 

[mtnelect]

That's how I got "Zapped" with 480 volts, while changing out a 277-volt light switch. My arm was numb for a day. After that incident, never worked anything live again. Isn't against the code to have more than one leg of 480 volts in a switch box ?

 

[roger]

Isn't against the code to have more than one leg of 480 volts in a switch box ?

If it was prohibited to have more than one leg (phase) of 480V in a box you couldn't have 480V available in that box

 

[mtnelect]

If it was prohibited to have more than one leg (phase) of 480V in a box you couldn't have 480V available in that box

I would think it should be a safety issue for 277 lighting circuits only ?

 

[tortuga]

these transformers are 3 phase 240 with the high leg. so there is a neutral needed for theses warehouses for the lighting.

Take a closer look at the lighting selection, it may be 120-277V in which case you could use 2 or 3 pole breakers and lighting controls and feed the lighting off the 240 L-L.

 

[wmthompson90]

Then anything downstream from that disconnect would be a feeder and an EGC would be required and your bare conductor would be that EGC and should not be used as a neutral.

so then unfused we could consider it a isolation switch? (for agricultural purposes). so at the isolation switch should one still install the grounded conductor (neutral) in the switch, bonded and grounded but still be able to consider it a neutral till it got to the first service disconnect?

 

[augie47]

so then unfused we could consider it a isolation switch? (for agricultural purposes). so at the isolation switch should one still install the grounded conductor (neutral) in the switch, bonded and grounded but still be able to consider it a neutral till it got to the first service disconnect?

That was my initial thought but after reading 547.9 and 250.32 it seems a EGC is needed under any condition other than grandfathered installations.

 

[wmthompson90]

That was my initial thought but after reading 547.9 and 250.32 it seems a EGC is needed under any condition other than grandfathered installations.

You are correct. Prior to 2008 code it was acceptable if it met certain conditions. Found on this site. Just search 250.32 on forums. Thanks!