1000's of watts of light? here are some tips.

[coldpurple]

Well I just joined so I guess I'll share some knowledge. First I would like to say that if you are not familiar with electricity this kind of work should be left to someone who is. Electricity is dangerous at any voltage, never work on anything live and make sure to ground everything. So lets say you've gone all out and your pushing a couple thousand watts of lights. First thing you want it is a timer but they usualy don't handle the load you need unless you spend big bucks. What you need is a contactor, like a giant relay it does the switching for you, the timer needs only to push the load of the contact coil. You'll want the run a 3 wire (2 hots one neutral) to your contactor and run half your lights on each phase. you'll need a 2 pole breaker with interlocking poles for your panel, Ground fault interupt breakers while expensive may be a good investment if your grow room is damp or wet. A good trick if you cant afford GFI breakers is to wire GFI recepticles is series with your lighting circuit. Make sure that your GFI recepticle is rated at a high enough amperage. You're contactor and timer should be installed in a dry location.

HID bulbs emit most of their light from the sides, mounting the bulbs sideways in white housings will yeild the most light to your plants. balasts should be kept dry as well, if you dont have a proper fixture with a proper housing for the ballast it may be better to install it in a remote location.

[stinkyattic]

I just use an Intermatic 60A rated time clock wired right onto my main panel with a dedicated 20A breaker running off it... very quick job for an electrician to install. I told him it was for electric baseboard heat to be installed in my attic.

Most HID bulbs you see in agriculture are 'horizontal burning', meaning they are designed to be burned sideways. If your bulb is 'vertical burning', it was designed to be run straight up and down, and should not be run on its side, which may shorten the life of the bulb.

[coldpurple]

20amp should be good up to 2400 watts, how much are you putting out if you dont mind me asking?

[stinkyattic]

That's for me and my utility to know.
But it is within the correct range for the size breaker and gauge of wire (12) that carries the current.

I would recommend that people run only up to 2000w on a 20A breaker, plus the fan that exhausts the lamp hoods, and NOTHING ELSE. Put all your other systems- pumps, supplemental lighting, a/c, dehumidifiers, etc. on OTHER breakers.

[rhizome]

So- if'n yer gonna run off both sides of the box, why not just wire the whole thing @ 240- which is what yer doing anyway, effectively- and use the same standards that are required for 240v (120vX2)?

Easy enough to tap the ballasts for 240- If you bought a decent ballast w/in the last two-three years, it's just a matter of changing the power cord.

I dunno- why re-invent the wheel? Esp when we're dealing with something that the original poster stated was dangerous? Why not just do it the right way? Only gonna cost a buck or two more... and if you're ever selling the building, you won't have to deal with oddball wiring...

I just don't understand the advantage to doing it this way...Why not do it right?

[coldpurple]

I just don't understand the advantage to doing it this way...Why not do it right?


The advantage is if you have allot of lighting to have 2 circuits instead of one big one and to balance the load. Its for safety really, plus its cheaper (smaller wire, cheaper breakers). If you had to run 2 circuits on the same phase you would need 2 neutrals to go with the 2 hots. Each phase can share a common neutral. You could run them all at 240 if you want to but then it will always be live unless you have all 2 pole switches. Its not odd ball wiring at all, most 240 appliances have 3 wire running to them, its mostly heating that doesn't use a neutral. If you aren't using contactors 240 volt timers are hard to come by as well.

[stinkyattic]

'Balance the load'? Forgive my noobness but isn't that the intent of a commercial 'flip-flop' relay?

[rhizome]

OK, so you're running two banks of lights alternating? That's what a UL listed flip-flop is for.

Honestly, we just disagree- I don't see how non-standard wiring could possibly be safer than standard. This is why we have electrical code. As described, your wiring schema would not be to code anywhere in the US- maybe CA is differant, I've never held a Canadian contractors license.

The schema you describe is maybe $6 US cheaper per light over a 6 light setup than wiring to code- not worth it to me.

240v timers are cheap and easy where I am- any electrical supply will have 240v mechanicals for about $20 US.

I always think about the person who is going to use the space next- If I bought a building and found something like this, I'd be pissed. If I were an insurance inspector/adjuster, I'd insist that it all be ripped out- and I'd want a healthy risk premium for any other wiring in the building that I couldn't see, because actual (bonded, insured) electricians were not employed.

I dunno- absolutely not safer, and it seems like a strange place to save $40-50 US.

But to each their own...