electrical help! 208v - 120/240

[irobot sd]

I am having all sorts of troubles. I am setting up a new room and getting an electrician over was not easy. I am running 2 MLCs (master lighting controllers). So this started out as one issue and quickly turned into 2. These are the CAP MLCs and one runs 120v/240v and the other is only 240v. So I told the electrician that the power at this op was 208v. We checked the existing wiring and everything was running 120v. So he puts in 2 seperate 2 pole 50a breakers one for each MLC. We ran 8/2 romex and everything seemed good. I only plugged in 1 light before electrician left and if fired right up everything seemed good.
So today i plug one ballast in the 240v MLC and another in the 120v MLC. There is a distinct difference as the 120 lamp is very bright and the 240 lamp not so much. So My guess is that at tops my ballast could only be running 208v??? thats why the lamp was dim. Then it gets worse.. I get all 120v power cords and run 6 lamps off of the 120/240 MLC and all the lights fire up and within 5 minutes the 50 amp breaker flips. So now my 240 MLC and 120 MLC both seem to be running improper. I know that 208 is 3 phase would i need a transformer? Or did my cousin in law electrician bite off more than he could chew? I need help I'm all ears

 

[irobot sd]

 

[Roof Berry]

are your ballast running on the 120/240 unit 120/240 as well?
are you using 600's or 1000 watters?

 

[irobot sd]

600's the ballasts are 120/240 switchable and i would like to run 240. The picture has the 120/240 controller on the left and on the right is only 240 controller

 

[Roof Berry]

also, if he did supply three phases to the 240 unit, he probably connected the third leg to the neutral. Remove that from the panel and unit, in the panel put it to the neutral bar. but you said he used a 2 pole breaker, and that is not right.
if you cant understand this, you need to take pictures of the connections

 

[Roof Berry]

120 unit.
open the panel, open the unit. tell me or show me how its wired

240 unit
there no way its 3 phase now that i think about it, because you ran 8/2.

 

[dgr]

irobotsd,
If you truly have 208V, it is wired in a Wye configuration. The differential between two legs is going to be 208V. They are 120 degrees out of phase; unlike our household 240V which is 180 degrees out of phase. square root of 3 * 120V is 208V. It is what it is.

It sounds like he also wired your 120/240 with 208V.

You will need a phase converter or a buck-boost transformer. OR, you need multi-tap ballasts and need to rewire them to 208V. If you don't have multitap transformers in your ballasts and don't want to buy a phase converter or buck-boost transformer, the cheapest solution would probably be to replace your 240V only MLC with a 120V one.

So, one new MLC and you should be able to run your lamps off of each at 120 volts. Run both MLCs off of single phase 120V which is one leg plus neutral off your three phase. Or rewire your transformers if they are multi-tap or replace all the transformers at about $100 a piece or a phase converter or buck-boost transformer.

BTW, a 1000W lamp at 240V draws about 4.2 amps plus losses. At 208V, that transformer is going to draw 867 equivalent watts. Of course, since the lamps are designed to run at 1000W, that 867 could produce significantly less light for you.

edit:
holy run around in circles. I would put in two 30 or 40 amp 120V breakers. Plug in a couple of MLCs that operate at 120V and plug the lights in and be done with it. That should get you squared away for the least investment if you don't have multi-tap transformers. A 40 amp 120V breaker should be able to run all 6 x 600W lights although I don't know what the start up current draw is. If your 50 amp two-pole breakers have a tie bar, he can pull the tie bar and simply use each side as a separate circuit.

 

[dgr]

BTW, most people on here will tell you that 8 gauge wire shouldn't be protected by a circuit breaker larger than 40 amps. Granted, NEC does allow 8 gauge/50 amp when the wire AND all termination points are rated at 75 C but for piece of mind, it'd be better to stick to 60 C and 40 amps.

 

[Marshall]

I think the switching side or contactor side of the MLC will handle 120 through 240 no problem. so 208 is fine.

On the 240 only unit, is that the load voltage or trigger voltage?


I am sure your major issue with the dim lighting is that the ballasts are set at 240 and only getting 208V. You need to open the ballast and see if they have a 208 multi-tap. If they do not, your cheapest option is to run them at 120 but that will increase your amperage so you may need additional circuits.

3600 watts/120v =30A

I would think the 50A circuit would work even with losses etc. Check for loose connections, see if the wire/breaker is heating up etc..




the 208 is easy to deal with. The issue here is lack of planning

 

[growshopfrank]

I think the switching side or contactor side of the MLC will handle 120 through 240 no problem. so 208 is fine.

On the 240 only unit, is that the load voltage or trigger voltage?


I am sure your major issue with the dim lighting is that the ballasts are set at 240 and only getting 208V. You need to open the ballast and see if they have a 208 multi-tap. If they do not, your cheapest option is to run them at 120 but that will increase your amperage so you may need additional circuits.

3600 watts/120v =30A

I would think the 50A circuit would work even with losses etc. Check for loose connections, see if the wire/breaker is heating up etc..




the 208 is easy to deal with. The issue here is lack of planning

the only thing to add is that the ballasts draw 5 amps at 208v vs 4.5amps at 240v

 

[irobot sd]

 

[irobot sd]

 

[irobot sd]

ok pic 1 - This is the panel without the cover. I've learned its 120/208 3 phase 5 wire. Is the 5th wire counting the ground I assume? 3 hots and a neutral going into a neutral bar. The majority of the breakers were already in the panel upon arrival. I noticed today that the left side is mostly 1 pole breakers and the right side is 2 pole breakers. there's (8) 20 amp 1 pole and a existing 50 amp 2 pole (on the left). We only bought one more 50 amp 2 pole breaker for the install (right side).

2nd pic shows the 3 phases and the new 8/2 we just installed also added the grounding bus

 

[irobot sd]

3rd pic shows both 50 amp breakers just a hot & neutral. notice how the breaker on the left is flipped to the middle thats running the 120/240 MLC. So I plugged this 120 MLC in again and tried 4 lamps. They all ran very bright but now the MLC is making a little bit of a humming noise almost like a magnetic ballast. I don't like this at all so i unplugged immediately

4th pic is the MLC without the cover.

Full panel view

 

[growshopfrank]

3rd pic shows both 50 amp breakers just a hot & neutral. notice how the breaker on the left is flipped to the middle thats running the 120/240 MLC. So I plugged this 120 MLC in again and tried 4 lamps. They all ran very bright but now the MLC is making a little bit of a humming noise almost like a magnetic ballast. I don't like this at all so i unplugged immediately

4th pic is the MLC without the cover.

Full panel view

the humming is likely the coil for the relay in the mcl and a normal thing try energizing the mcl trigger wire without a load and see if it still is loud once it warms up

 

[irobot sd]

I tried this and the relay trigger makes no sound until a ballast gets plugged in. Today I tried again and went with only 2 lights on. The MLC makes a humming noise still and when I feel the 120 power cord it feels very energized and gets hot after about 20 minutes. The hoods are also getting very hot. Without a ammeter there is no way to tell if 208 is going into my 120/240 MLC.

 

[Roof Berry]

first, you are running 240 on both boxes, there is no 208 three phase anywhere in your setup, so rule that out. flip the switch on ballast and mlc to 240.

second, i did a quick search on your units because i didnt know what they were for, depending on the model you have, you could be overdoing it, they are designed for up to 4 1000's.

do the switching of the ballast and unit to 240, then remove to lights on each, as i believe you said you had 6.

tell us how that works

 

[1971]

hey berry,

more than likely he is not running 240v on either box unless there is a possibility of a delta configuration. so the issue at hand is that he is under-powering his setup. more than likely he is running 208v. interestingly only one leg is phased with blue tape.

the boxes he has don't care if it is getting a 120/208/240 source, but his lights will big time.

it wouldn't be cost effective to get a transformer to adjust the voltage, and unless you are using magnetic ballasts with a 208 tap, you'll need to run everything at 120v. I'm not sure if digital ballast manufacturers allow their ballasts to be run at 208v.

if your power cord is getting hot, something is wrong and you are risking a fire hazard.

 

[1971]

just an fyi, you can't run romex in a commercial application.

 

[irobot sd]

1971 you are exactly correct. Both boxes are on 208v I've come to find out. That explains one not being bright enough and the other being way to hot. So it seems the easiest fix is to remove the 240v MLC and replace it with another 120v unit. Now my new question is what changes need to be made to put the boxes on a single phase 120? What is my other choice to run AC or EMT cables?