# Single phase load center on a 3 phase pannel



## five.five-six (Apr 9, 2013)

Seems odd that I don't know the awnser to this, seems I have done it before.

Industrial customer has a new lineup of 3 40' shipping containers converted to storage. 

Out there I have 2 #10's + #10 ground and neutral. It's about a 150' run. 

They want LED lighting, a few wall packs, 3 double duplex receptacles + 2 ice machines for the drivers. ice machines are 13.3 A FLR and call for a minimum 17A single phase circuit. 


Running bigger or more feeders/branch from the panel is prety much out of the question.

I want to put 30A breakers on the #10s and feed a small single phase load center to feed the recepticals, lighting and ice machines. The Lighting is 200 wats of LED so it all depends on what the plan on using the receptacles for and my understanding is it will be for battery chargers for cordless drills and general convienance.


----------



## backstay (Feb 3, 2011)

five.five-six said:


> Seems odd that I don't know the awnser to this, seems I have done it before.
> 
> Industrial customer has a new lineup of 3 40' shipping containers converted to storage.
> 
> ...


Is there a question in this.


----------



## daveEM (Nov 18, 2012)

No that won't work. 

Put a 100 amp 3 phase 42 circuit panel out there and be done with it. Well maybe a 60 amp 3 phase panel.


----------



## Southeast Power (Jan 18, 2009)

five.five-six said:


> Seems odd that I don't know the awnser to this, seems I have done it before.
> 
> Industrial customer has a new lineup of 3 40' shipping containers converted to storage.
> 
> ...


You are going to lose those ice machines.

I would get 480 volts out there.
Set a small transformer and then use a 120/240 panel so that you can isolate the loads when needed.


----------



## Ultrafault (Dec 16, 2012)

Opps
Nvm


----------



## backstay (Feb 3, 2011)

daveEM said:


> No that won't work.
> 
> Put a 100 amp 3 phase 42 circuit panel out there and be done with it. Well maybe a 60 amp 3 phase panel.


I would say the equipment is single phase being he said two #10 hots and a #10 neutral.


----------



## five.five-six (Apr 9, 2013)

backstay said:


> Is there a question in this.


Can I put a single phase load center on a 3 phase panel? I've put plenty of 2 pole disconnects on 3 phase panels but I don't recall ever using a single phase load center on a 3 phase system.


----------



## five.five-six (Apr 9, 2013)

Suncoast Power said:


> You are going to lose those ice machines.
> 
> I would get 480 volts out there.
> Set a small transformer and then use a 120/240 panel so that you can isolate the loads when needed.


I like this idea except that there is a 110 circuit off the building's UPS in the conduit for a piece of network equiptment out there.


----------



## drspec (Sep 29, 2012)

five.five-six said:


> Can I put a single phase load center on a 3 phase panel? I've put plenty of 2 pole disconnects on 3 phase panels but I don't recall ever using a single phase load center on a 3 phase system.



if you have a neutral theres no issue

if its a high leg panel just make sure you feed the sub panel with a 240v breaker and not a 120/240v slash rated breaker


----------



## Norcal (Mar 22, 2007)

drspec said:


> if you have a neutral theres no issue
> 
> if its a high leg panel just make sure you feed the sub panel with a 240v breaker and not a 120/240v slash rated breaker



When a neutral is present, a single phase load should not have the high leg, there are going to be problems if it done that way, a straight 240 volt load using the high leg & another phase is fine when using a 2 pole breaker w/ a 240V rating. 

A farm shop w/ a 120/240V 3Ø service(PG&E loves them for AG services) had a 230V 1Ø Hoshizaki ice machine hooked up to supply the farm workers, Hoshizaki 208-230V single phase machines require a neutral because the water pump, condenser fan, valves are 120V, the electrician used the high leg & another leg for the machine & the machine would not work because the board shuts the machine down when the L-N voltage exceeds 147V, there are other machines where that would have been a disaster, the Hoshizaki's simply reset when the high voltage condition is corrected.


----------



## papaotis (Jun 8, 2013)

if you use a double pole breaker on a 3 phase system you are only getting 240 single phase


----------



## backstay (Feb 3, 2011)

five.five-six said:


> Can I put a single phase load center on a 3 phase panel? I've put plenty of 2 pole disconnects on 3 phase panels but I don't recall ever using a single phase load center on a 3 phase system.


Yes 




papaotis said:


> if you use a double pole breaker on a 3 phase system you are only getting 240 single phase


No, not single phase. The two hots are 120 degrees out of phase. And it might be 208 volts not 240.


----------



## B-Nabs (Jun 4, 2014)

five.five-six said:


> Can I put a single phase load center on a 3 phase panel? I've put plenty of 2 pole disconnects on 3 phase panels but I don't recall ever using a single phase load center on a 3 phase system.


Yes, it's done all the time, think apartment buildings where the unit panels are single phase taken off of a three phase meter stack.

Sent from my SM-G920W8 using Tapatalk


----------



## five.five-six (Apr 9, 2013)

drspec said:


> if you have a neutral theres no issue
> 
> if its a high leg panel just make sure you feed the sub panel with a 240v breaker and not a 120/240v slash rated breaker


No stinger.


----------



## macmikeman (Jan 23, 2007)

Not against code directly unless you imbalance the one leg you don't use. The practice is frowned upon though for single instance jobs, but more or less legal. As stated above, when feeding single phase panels in a multi unit dwelling the phase feeder conductors are rotated around the wye to balance things out evenly and take current off the neutral as much as possible. I've done what you are describing about a half million times. Always passed.


----------



## HackWork (Oct 2, 2009)

backstay said:


> No, not single phase. The two hots are 120 degrees out of phase.


We still have always called it single phase.

When you install a 2-pole breaker in a 3-phase panel, what do you call it, 2-phase? We would say "single phase 208v".


----------



## Going_Commando (Oct 1, 2011)

HackWork said:


> backstay said:
> 
> 
> > No, not single phase. The two hots are 120 degrees out of phase.
> ...


Yup. We call it single phase too, since 2 phase they would be 180 degrees out of phase.


----------



## B-Nabs (Jun 4, 2014)

Going_Commando said:


> Yup. We call it single phase too, since 2 phase they would be 180 degrees out of phase.


As far as I'm concerned, 180 degrees out of phase is single phase. "Two phase" traditionally refers to the now basically obsolete system with two phases that are 90 degrees out of phase. Used for motors before the widespread adoption of three phase. Google Scott T connection.


----------



## backstay (Feb 3, 2011)

HackWork said:


> We still have always called it single phase.
> 
> When you install a 2-pole breaker in a 3-phase panel, what do you call it, 2-phase? We would say "single phase 208v".


He said "get" not call. You "get" two phases and "call" it single phase, I get that.



B-Nabs said:


> As far as I'm concerned, 180 degrees out of phase is single phase. "Two phase" traditionally refers to the now basically obsolete system with two phases that are 90 degrees out of phase. Used for motors before the widespread adoption of three phase. Google Scott T connection.


I don't think the phases change their angles to each other when you run them though a breaker.


----------



## five.five-six (Apr 9, 2013)

I think (hope) we all know it would be 2 phases but we just call it single phase and the load center I am thinking about would be single phase. it's like a 3 way or 4 way switch... there's no such thing but it's what we call them.


----------



## cabletie (Feb 12, 2011)

Maybe I'm not remembering this right, but single phase 120/240 would not have any phase angle between them. There is only one phase with a center tap.


----------



## Southeast Power (Jan 18, 2009)

five.five-six said:


> I like this idea except that there is a 110 circuit off the building's UPS in the conduit for a piece of network equiptment out there.


What would be the difference if the single phase 480 and transformer I proposed is in the conduit or the 208 you have now?
I'm thinking that you could decrease your I2r losses going with the 480 and getting it back to 120/240 single please with a small transformer.


----------

