# wiring lighting controller to sub-breaker



## greenfriend (Dec 19, 2008)

Hi, can anyone offer detailed instructions how to wire a 40 amp line from my lighting controller to the subbreaker.

I am using a 40 amp 240V MLC-8 controller with 120V trigger cable.  I have 8/3 wire - red, black, white, and copper ground wire.  I have already wired one end to the controller.

The sub-breaker is a 200 amp 3 phase system

I dont have much electrical knowledge - this is what the label on the breaker reads:

200 amp max
240 VAC/VCA  3 FASE - 3 HILOS
208Y/ 120 VAC/VCA 3PH-4W ; 3 FASE - 4 HILOS
240/120 VAC/VCA 3PH-4W DELTA; 3 FASE

Thanks!


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## Growdude (Dec 20, 2008)

The only thing I can tell you is you will need a 240v 40 amp 3 pole breaker in your panel, you will use 2 of the 3 poles and a ground .


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## leafminer (Dec 20, 2008)

I can tell you, but I will need some more info.
1. What is the line voltage where you are?
2. How many lights and what power are they?
3. What else do you have that takes power, e.g. pumps, fans.

It sounds like you are planning something really big. Your supply cable is #8AWG and you're running three phases by the look of it? Do you really need all that power? And 220V installation? I don't understand, because your wiring colours are US standard and for three-phase you'd be running red-blue-yellow not red-black-white. If you wanted to run two phases you'd normally run 4 wires (two live, two neutral) and a ground.
If you actually are planning to use two phases with your three-core cable, remember your maximum current will be limited to the single return wire, the white, with red and black being the two live phase wires. With #8 cable the limit is 60A for the usual TW cable, which is 30A per phase, or roughly 3.5 KVA per phase (total 7 KVA; KVA is approx the same as a KW but we use KVA because the HID lamps are not a pure resistive load)
If all this leaves you going huh? just specify your set up and I will advise.


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## greenfriend (Dec 20, 2008)

leafminer said:
			
		

> I can tell you, but I will need some more info.
> 1. What is the line voltage where you are?
> 2. How many lights and what power are they?
> 3. What else do you have that takes power, e.g. pumps, fans.
> ...


no 220V at all. just 120, 208, 240

I have 8 1000W 240V ballasts connected to the 40 amp 240V lighting controller.  should be using 36 amps total

All pumps, fans, etc. are plugged into regular 120V outlets.

I have 240V outlets in my room as well but they are the wrong shape (look like regular 120V outlet upside down)  while my ballasts have horizontal plugs.  so i have both 120 and 240V plugs, but im only using the 120V.

The main breaker has a 600 amp max load, the sub-breaker has 200.  dont really need all that power, but i could add more lights and run A/C and dehumidifiers without worrying about power failure.

The 8/3 wire with black and red live and white and copper ground was the wire req'd for the controller.  Is it possible to use this wire to connect to a 3 phase sub-breaker?  Im sure is supplies 240 VAC, just not sure where to connect the wires to in the sub-breaker

thanks


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## Growdude (Dec 21, 2008)

It can be done like I told you.
Dont hook it up to the 200 amp breaker you are going to have to have a 40 amp breaker, if your panel is 3 phase your going to use 2 of the 3, dont matter which 2 and the neu wire.

# 8 is fine.


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## leafminer (Dec 21, 2008)

greenfriend said:
			
		

> no 220V at all. just 120, 208, 240
> 
> I have 8 1000W 240V ballasts connected to the 40 amp 240V lighting controller.  should be using 36 amps total
> 
> ...



OK, now I understand. Pro grow. Yes, you're using 3-phases. Now it depends where you are; I have had some experience wiring industrial premises in the US and they have a really weird scheme where two phases are at 120V and one is 'hotter' (the 'high' leg) so you get line to line phase volts = 240V as I recall. That's called a "high leg delta". Your 120V outlets are wired across either of the two 'low' phases (NOT the high leg) and neutral.

  So assuming that's what you have you'll connect your 240V across any pair of wires (but check with your voltmeter to make sure). You should equalise the line currents as far as possible; if you have 8 x 240V 1KW ballasts, wire them 2 - 3 - 3 on the triple controller, the current draw will be approx. 8 - 12 - 12 amps respectively. If you put them all in parallel on one line with a single breaker, you will indeed draw around 33A and for that your cable rating will also be OK. With that many 240V ballasts I think it would be a good idea to use an earth leakage protection breaker which can save your life in the event of an electric shock.


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## nycdiesel (Feb 10, 2009)

Just because you have a 3 phase panel you don't need to use all three phases. You connect a 2 pole breaker. 8g wire is correct for 40 amps. You need simple 8/3 witch you can find at home depot. White goes into neutral bar black and red go into 2 pole 40amp breaker. You don't need two neutrals (white) The electricity is on two phases. Three phase you would use 8/4 black red blue and white (neutral) thats 380v I've never seen  ballasts for 380 thats usually reserved for motors . If you have the option use 277v USE IT (much cheaper electric bill) you can use with 10/2. With 277 black goes into single pole 30amp breaker white into neutral bar. Do NOT USE 2 pole breaker on 277v panel u get 480 and will start fire. 

PS Shut off sub panel before working in it. Be careful turning it back on ( before you turn it back on use a connectivity tester to make sure there isn't a short somewhere. Touch one lead to neutral bar other to each phase if you hear a beep DO NOT FLIP SWITCH


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