# white in SO cord as 3rd phase conductor



## TBarwick1 (Sep 4, 2010)

Hello All, I am new to this forum and this may be a dumb question but here goes:
If I am wiring a 208 volt 3 phase piece of kitchen equipment that pulls 33 amps and will run more than 3 hours (continuously) I multiplied by 125% which is 41 amps so I sized my breaker to a 45 amp 3 pole and will be using 3 #8 copper THHN wires with a #10 green ground. The appliance came with no cord so I was going to use 8/3 with ground 4 wire SO cord on the equipment with a male plug. Can I mark the white wire in the SO cord blue for my 3rd phase? Also can I use a 125/250 volt 4-wire range cord with male range plug on it and a flush mount 4-wire range receptacle using the silver neutral terminal as my 3rd blue leg? I don't do much 3 phase work and may be looking at this all wrong. Is there a different type of cord with 3 colors and a green, no white, that I should be using? Do they make a 3 phase 4 wire receptacle and male plug just for such a 3 phase application? Hoping someone can set me straight. Thanks for any advice.


----------



## Bob Badger (Apr 19, 2009)

TBarwick1 said:


> Hello All, I am new to this forum and this may be a dumb question but here goes:
> If I am wiring a 208 volt 3 phase piece of kitchen equipment that pulls 33 amps and will run more than 3 hours (continuously)


I doubt it meets the Article 100 definition of a continuous load.




> I multiplied by 125% which is 41 amps so I sized my breaker to a 45 amp 3 pole and will be using 3 #8 copper THHN wires with a #10 green ground.


Sounds OK, but a 40 would be fine for the 33 amp unit.



> The appliance came with no cord so I was going to use 8/3 with ground 4 wire SO cord on the equipment with a male plug.


Is the appliance listed for cord connection or is it set up for raceway like LFMC?




> Can I mark the white wire in the SO cord blue for my 3rd phase?


Yes





> Also can I use a 125/250 volt 4-wire range cord with male range plug on it and a flush mount 4-wire range receptacle using the silver neutral terminal as my 3rd blue leg?


No.



> Is there a different type of cord with 3 colors and a green, no white, that I should be using?


I am sure it can be ordered but I have never seen it used.



> Do they make a 3 phase 4 wire receptacle and male plug just for such a 3 phase application?


You bet they do.

It looks like you need a NEMA 15-50R and 15-50P

http://www.stayonline.com/detail.aspx?ID=4752

By the way, you can order the plug 'straight' or 'angle' you will probably want the angle.


----------



## oldtimer (Jun 10, 2010)

Bob Badger said:


> I doubt it meets the Article 100 definition of a continuous load.
> 
> 
> 
> ...


 Pin and sleeve connectors work well, or twist- lock male and female cord ends.


----------



## TBarwick1 (Sep 4, 2010)

Part of this equipment is a steamer and stays on in a preheated mode so it is ready at all times to use so I figured it would be considered continuous operation? 33amps x 125% is 41amps and my next largest size breaker is 45.

The piece of equipment came with a cord connector on the back of it from the factory and my customer wants it to be able to be disconnected easily so they can move it out and clean behind it occasionally.

Is there a code article that would allow me to mark the white wire in the SO cable with blue and use it as a hot?

And thanks for the link to the male plug and flush receptacle. This is exactly what I needed.


----------



## oldtimer (Jun 10, 2010)

TBarwick1 said:


> Part of this equipment is a steamer and stays on in a preheated mode so it is ready at all times to use so I figured it would be considered continuous operation? 33amps x 125% is 41amps and my next largest size breaker is 45.
> 
> The piece of equipment came with a cord connector on the back of it from the factory and my customer wants it to be able to be disconnected easily so they can move it out and clean behind it occasionally.
> 
> ...


Try; elecDirect.com for pin and sleeve, many fast food places use them.


----------



## Bob Badger (Apr 19, 2009)

oldtimer said:


> Try; elecDirect.com for pin and sleeve, many fast food places use them.


Pin and sleeve is a fine choice but at a higher price.

I have to keep about $2000 worth of pin type connectors in stock for one of our customers that uses a lot of them.


----------



## Bob Badger (Apr 19, 2009)

TBarwick1 said:


> Part of this equipment is a steamer and stays on in a preheated mode so it is ready at all times to use so I figured it would be considered continuous operation? 33amps x 125% is 41amps and my next largest size breaker is 45.


It does not matter if part it stays on or the switches stay on the unit it self will cycle.

You can certainly call it a continuous load if you want but it is not needed.



> Continuous Load. A load where the maximum current is
> expected to continue for 3 hours or more.


It will not remain at the maximum current for 3 hours.




> The piece of equipment came with a cord connector on the back of it from the factory and my customer wants it to be able to be disconnected easily so they can move it out and clean behind it occasionally.


The fact it came with a cord connector certainly suggests it is listed for use with cord as directly required by 400. 



> 400.7 Uses Permitted.
> (A) Uses. Flexible cords and cables shall be used only for
> the following:
> 
> ...





> Is there a code article that would allow me to mark the white wire in the SO cable with blue and use it as a hot?


200.7(C)(3)



> And thanks for the link to the male plug and flush receptacle. This is exactly what I needed.


No problem.

You can buy a 15-50P and 15-50R from any device manufacturer or decent supply house.


----------



## CTshockhazard (Aug 28, 2009)

I agree with the info already given, and that it's not a continuous load. Just wanted to caution you that if it was indeed a continuous load, the flexible cord would need to be a #6 as a #8 SO with 3 current carrying conductors is only good for 35 Amps (see Table 400.5(A)).


----------



## TBarwick1 (Sep 4, 2010)

If the nameplate load is 33 amps and it is a non continuous load should it be a 35 amp 3 pole breaker with #8 wire to my receptacle and a #8-3 w/ground SO cord? Or should it be a 40 amp 3 pole breaker, #8 to my receptacle, and #6-3 SO cord? Thanks for the help


----------



## JohnJ0906 (Jan 22, 2007)

Bob Badger said:


> It looks like you need a NEMA 15-50R and 15-50P
> 
> http://www.stayonline.com/detail.aspx?ID=4752
> 
> By the way, you can order the plug 'straight' or 'angle' you will probably want the angle.


I agree the angle is the way to go - the straight plug will cause the unit to sit too far from the wall.


----------



## Jlarson (Jun 28, 2009)

Just throwing this out there for the OP. If you go the angle plug route make sure the receptacle is installed so that when the cord is plugged in the cord is pointing down not up.


----------

