# 208/110 3 phase power



## greenfriend (Nov 20, 2008)

hi all, 

does 208/110V 3 phase power work with 240V 1000W ballasts?  There are six 110V plugs and 3 circular 30 amp plugs in the room.  Is it possible to run 8 1000W lamps in this setup, or what electrical changes would need to be done?
Thanks!


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## Growdude (Nov 21, 2008)

greenfriend said:
			
		

> hi all,
> 
> does 208/110V 3 phase power work with 240V 1000W ballasts? There are six 110V plugs and 3 circular 30 amp plugs in the room. Is it possible to run 8 1000W lamps in this setup, or what electrical changes would need to be done?
> Thanks!


 
If its 208, not 220 then it wont work unless your ballast is multi tap and is wired for 208.

Also 3 phase power will work, you just have to use 2 of the 3 legs of power. Just leave one of the hot wires unused.

Are all 3 twist lock plugs (circular plug) on the same 30 amp breaker?
If so you can get ~6, 1000 watt lights @ 220 volts, less at 208.


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## greenfriend (Nov 21, 2008)

Growdude said:
			
		

> If its 208, not 220 then it wont work unless your ballast is multi tap and is wired for 208.
> 
> Also 3 phase power will work, you just have to use 2 of the 3 legs of power. Just leave one of the hot wires unused.
> 
> ...


 
ya the ballasts only run on 240V, not sure how to use just 2 of the 3 legs, (should i been looking 4 an electrician?) and unfortunately all three circular plugs are on the same 30 amp line.

a guy at the hydro store told me that the 240V ballasts will work if it can be upgraded to a 40 amp breaker.  but i think imma need at least a 90 amp line, or multiple breakers for running 8 lamps.


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## tesla (Nov 21, 2008)

My ballast can be wired for 208,220 and 240. I can just put the wire for whatever voltage I got coming in.I got a older one though.


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## clanchattan (Nov 21, 2008)

8000/208 = 38 amps so you will need to upgrade to a 50 amp breaker to allow the 20% cushion, 

208 three phase (or any three phase for that matter, except wye transformers) is three hot wires from a breaker. you have to have a 3 phase service from the power company.

anyway,

phase a : 110v
phase b : 110v
phase c : 110v

if you read each leg to ground you get 110v

if you read between any two of the three you get 208v

you should allways wire three phase in a pattern of:

light 1 : a phase & b phase
light 2 : b phase & c phase
light 3 : a phase & c phase
light 4 : wire as light 1 and so on

this balances the load across all 3 phases.

before popping in a larger breaker you have to determine the wire size on your circuit. putting a 50 amp breaker in place of a 30 amp with a 10 awg wire is a recipie for a fire, the wire is not large enough to handle the amperage drawn by the equipment. for a 50amp circuit you'll need a 6 awg wire.

if you are unsure call an electrician. single phase is hard to understand for some and 3 phase can be a nightmare. a electrician is alot cheaper than fighting the insurance company to replace a house burnt down by dangerous wiring that you d.i.y.'d


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## Mutt (Nov 21, 2008)

> if you are unsure call an electrician. single phase is hard to understand for some and 3 phase can be a nightmare. a electrician is alot cheaper than fighting the insurance company to replace a house burnt down by dangerous wiring that you d.i.y.'d


:goodposting:
still confused why'd you have 3-phase unless its a commercial building. I have wired up 480V 3-phase equip...if you don't know don't mess with it. really easy to screw up with 3-phase if you don't know...and it packs a lot more current than res.
I you got 3-phase there should be some single phase 220v in there too. I'd wire off them.


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## greenfriend (Nov 21, 2008)

clanchattan said:
			
		

> 208 three phase (or any three phase for that matter, except wye transformers) is three hot wires from a breaker. you have to have a 3 phase service from the power company.
> 
> its a new commercial building, so i believe it is a 4 wire wye 3 phase system.


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## greenfriend (Nov 21, 2008)

thanks all for the help!  If im understanding correctly, it is possible to run 240V ballasts from a 208/110V 3 phase power, but i'll need an electrician to rewire a few things.  maybe it would be easier to look 4 a different space.  what is the optimal electrical setup to run 8 or more lamps?


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## Growdude (Nov 21, 2008)

greenfriend said:
			
		

> thanks all for the help! If im understanding correctly, it is possible to run 240V ballasts from a 208/110V 3 phase power, but i'll need an electrician to rewire a few things. maybe it would be easier to look 4 a different space. what is the optimal electrical setup to run 8 or more lamps?


 
Im telling you if its 208 you cant wire a 220/240 ballast to it unless
the ballast must be multi tap.

Sound like your growing commercial anyway


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## Mutt (Nov 21, 2008)

Electricians typically charge more for 3-phase....utility bill might be higher too for the 3-phase service.
I'd still price it both 3-phase and single see which one comes out better.


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## nycdiesel (Dec 5, 2008)

I'm an electrician - CALL SOMEONE IN TO WIRE IT. 

Way to many variables. 

just because the receptacles are rated for 30amp doesn't mean the wiring is.

Don't play with 3-phase 380v will kill you. Many 3-phase systems are 277/480v. 277v will kill you. If you don't die during wiring and turn system on it may work for a little while and then burst into flames. 

I recently replaced a bunch of fixtures cause some ***hole put spiral fluorescents into a 277v socket. They worked fine but when they came in the next day the place was full of smoke and the only thing left of the fluorescents were a couple piles of melted plastic. THEY WERE LUCKY!

If your lucky your place is 277 it will be cheaper to operate.


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## mendo local (Dec 5, 2008)

8 or more lights? sounds like more than a medical problem.


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