2 Lights 1 Ballast

[justaseed]

ok i see, 1 ballast cannot run 2 lights simultaneously, it's just done with a relay and timer. that makes much more sense. i was thinking that it was just 2 transformers,caps, and igniters in 1 housing. either way it's not a bad idea.

[kindprincess]

i'm going to be setting up this way in a week or two...

[TestPilot]

Not to start trouble, but couldn't you drive 2 bulbs of half the rated wattage of the ballast?

Anyway, as mentioned, you're referring to a relay or interfacing relay. If you just want to control multiple ballasts from the same timer you use a relay. There's a good tutorial on hydroponics.net for building your own 240V/30A relay to control up to 4 x 1000W from one timer.

On a side note: As a safety precaution I think it's best to control your hood cooling and ballasts from the same timer and preferably the same circuit just in case you're cooling timer failed or you tripped the breaker. It seems most fans run on 120V so you can't just plug them into the same circuit as your 240V lights.

One solution I've seen is a standalone load center that takes a 30-50A double pole (240V) line. It's divided from there into 240V/20A (4 x 1000W) and a 10A/120V (cooling and timer) circuits. It's still two separate circuits on two breakers it's not perfect. Add a high temp override in between your timer and trigger cable and it would solve this.

Otherwise you can just use a multitap on your timer output to run 2 x 120V trigger cables and drive a 120V relay as well as a 240V/30A relay. Add a high temp override in between the timer and multitap and your set.

There is the link for wiring 2 rooms to one ballast, but they don't run simultaneously. It's just a switch to select which bulb the ballast is lighting. Too much trouble IMO.