Growroom Electricity and Wiring

[rives]

Sorry, I missed this. You could buy a transformer to do this with, but it would very likely cost more than replacing the ballasts with the correct ones. There would also be the additional running cost of the transformer losses - though relatively minor, every time you run through a transformer there is some loss. I would think that you are better off biting the bullet and buying the correct one, and trying to sell your 480v ballasts either on eBay or to an industrial plant.

 

[macncheese]

Yeah that is what I was leaning towards. Thanks rives.

 

[avant gardener]

if you bought them from a retail establishment, you ought to be able to return them with little trouble. if you bought them on the street, hopefully you got them cheap enough that the hit won't be that big even if you can't flip them.

 

[Lathund]

I just bought a Spudnik Prima Clima reflector (air cooled). I totally suck at electrics, my digistar ballast have 3 wires, 2 black and one that's green/yellow. I know that the green/yellow one is the earth, but what about the 2 black ones? Does it matter in wich side of the socket I plug them in?

And in the installation notes it says "third cable (earth) must be fix by screw to the side part of the reflector". I only have one place where it seems to work, wich is pretty close to the socket. Will that work?

 

[avant gardener]

post pictures if you're able.
and tell us where in the world you are.

 

[Lathund]

post pictures if you're able.
and tell us where in the world you are.

I'll get some pictures tomorrow.

I'm located in Europe.

 

[RSA]

Based on what I've been told, for a 15 amp circuit it's 'capacity' is 1440W.

To be considered in the 'safe' range, only max it out @ 80% capacity, or ~1152W.

So, considering that...

1000W ballast - safe to run (alone) on 1 outlet/15A circuit?

People run 1500W space heaters all day on 15A circuits, some have problems some don't. My option is to run such a space heater on the circuit, or 1 x 1000W ballast. Obviously 500W less is safer, but I want to be sure I'm not putting myself in danger by running 1000W being safe max on 15a is 1152W.

 

[rives]

RSA, you are doubling the safety factor. Volts x amps = Watts, so 15a x 120v = 1800watts. 1800w x .8 = 1440 watts. This safety factor is only meant for circuits that are "continuous duty", which is defined as 3+ hours of uninterrupted usage. The biggest issue that is addressed with this rule is to eliminate potential nuisance tripping of the breaker from manufacturing tolerances, ambient temperatures, etc. In fact, there are breakers that are rated for continuous duty at full load, but they are difficult to find and are substantially more expensive. You could actually run your light (don't forget the ballast losses), with intermittent loads like pumps or whatever bumping up to the full rating of the circuit.

 

[yerboyblue]

Based on what I've been told, for a 15 amp circuit it's 'capacity' is 1440W.

To be considered in the 'safe' range, only max it out @ 80% capacity, or ~1152W.

So, considering that...

1000W ballast - safe to run (alone) on 1 outlet/15A circuit?

People run 1500W space heaters all day on 15A circuits, some have problems some don't. My option is to run such a space heater on the circuit, or 1 x 1000W ballast. Obviously 500W less is safer, but I want to be sure I'm not putting myself in danger by running 1000W being safe max on 15a is 1152W.

What rives said is very on point. You will be fine with the 1kw ballast, even with enough room for other things like smaller fans. You won't be able to run the 1500w space heater (unless it is a 220v heater and circuit). I suspect people that run those heaters on 15A have them cycling on and off frequently, or are only running on half power as most of those things have settings like that. I've tripped breakers all day with those things until I ran new 20A lines.

 

[Lathund]

post pictures if you're able.
and tell us where in the world you are.

Here are some pictures.

Picture one: I figured one black on each side of the socket and the ground to the top screw?

Picture two: This is for my exhaust fan. Do I just match the colors in the plastic thing? Do I need some specific kind of cable?

Thanks in advance

 

[snarglefarf]

So this question may have already been asked or maybe im a dumbass but I'm not reading 89 pages of posts and I'm new so I should bust my post cherry.... gonna build a flower room. Was thinking 2k hps and was wondering if its possible to somehow wire 2 120v 15A circuits to a single 240v circuit.

 

[rives]

So this question may have already been asked or maybe im a dumbass but I'm not reading 89 pages of posts and I'm new so I should bust my post cherry.... gonna build a flower room. Was thinking 2k hps and was wondering if its possible to somehow wire 2 120v 15A circuits to a single 240v circuit.

You could, but it would probably be easier just to convert an individual 120v 15a circuit to a 240v 15a circuit. The wiring would need to be isolated in the distribution center - the hot wire should be easy, it's already on a breaker. The breaker would need to be changed from the existing single-pole style to a double-pole, and the hot wire from the single-pole breaker moved to one side of the new breaker. The matching neutral wire from the cable feeding the circuit would need to be lifted off of the neutral bus and moved to the other side of the breaker. This white wire should be marked with phase tape to indicate that it is no longer being used as a neutral - the different color tape shows that it is now a hot wire.

The same thing would be done at the receptacle end of the circuit - the white wire gets taped with a different color to denote it's new usage, and the receptacle would need to be changed out to a Nema 6-15 style (240v, 15a).

It's critical that you make certain that the circuit only feeds the receptacle(s) that you change to the new style - it is very common to "daisy-chain" several receptacles together and feed them all from the same circuit. If you miss a receptacle and convert the circuit over, whatever gets plugged into the missed receptacle next is going to have a very, very short lifespan.

 

[avant gardener]

one more small thing. make sure that white wire isn't shared with any other circuits, e.g. if it belongs to a 3-wire or is pigtailed to another circuit in a box along the line. neutrals are often shared. i have definitely cooked stuff before by not chasing my neutrals before switching them into 240 hot legs.

 

[snarglefarf]

Thanks for your answers. Sounds a bit complicated for me. So if I were to just replace the existing wire with a thicker gauge to switch it to 240, how would I run it through the walls without tearing out walls? Don't really wanna destroy walls in my finished basement

 

[avant gardener]

1. pulling a thicker wire (and putting in a bigger circuit breaker) will give you more ampacity, but in itself it won't let you run 240. the difference between 240 and 120 is that 120 has 1 hot, 1 neutral, and a single pole breaker while 240 has 2 hots, no neutral, and a 2 pole breaker.

2. i'd need pictures to say exactly how i'd run the new wire, but i can venture a guess. assuming we're talking about residential work in a dry location, there's probably no raceway. generally speaking, the easiest way to pull romex where there's already an existing wire is to tie a string to the existing wire and pull it back from the receptacle to the panel when you're demo'ing the old wire. then tie the new to the string and pull it back.

3. if there's more than a single turn in the run, you're probably going to need access in at least one place. attics and crawlspaces are probably your best shot if you're not trying to dig around in the walls. you seem like an inquisitive type though. maybe while you're teaching yourself electrical, you can learn/practice mudding and taping drywall too

4. if you're confused, don't fuck around with your safety. find a qualified electrician to walk you through it. a friend of mine in oregon just had a fire in her house because her clueless handyman switched a 15 amp breaker to a 20 to "fix" a nuisance trip. losing your grow and your home in a matter of minutes is bad enough. luckily she was a fully compliant medical grower or she would have had some much bigger problems though.

 

[rives]

one more small thing. make sure that white wire isn't shared with any other circuits, e.g. if it belongs to a 3-wire or is pigtailed to another circuit in a box along the line. neutrals are often shared. i have definitely cooked stuff before by not chasing my neutrals before switching them into 240 hot legs.

Excellent point, and not a small thing! Having a bunch of neutrals tied common in the field is very common in residential work.

 

[diffusing]

hey,

Noob electrical question here. I've been playing around with the formulas at the beginning of the post for a while now, and am fairly confident i'm screwing something up somewhere. Just wanted to ask for some help with the calulations to determine the gague of cable required to be run to the flower room.

the plan is to run 10 x 600watt gavita pros (US) .. the specs on the ballast label are:
P - 634 Watt
V - 240 V AV +- 10%
I - 2.7 A (average)

the distance of the run is approx 60-70 feet. so going with 70 to be safe... and obviously running 240V

the run will be going into a power distribution box, and split from there within the room.

I also have 2 seperate 14/2 runs into that room that are idle atm for fans and things down the road.

So my question is, what would be an appropriate gague cable for that run ?(currently its a #8) I would prefer to rerun it now while the contruction is going on rather than later if something more aggressive is needed. Don't want to find out later as the lights get added that I screwed up with the cable that was run and my math.

thanks guys for any help!

 

[sunset limited]

6340 watts / 240 v = 26.5 amps
remember your 80% rule, so 26.5 amps / .8 = 33 amps

voltage drop needs to be considered for runs longer than 100 feet, so you're alright there.

you need a 40amp circuit.
8 awg copper is rated for that ampacity.
unless i've missed something, you're good to go amigo.


fyi, your voltage drop on that run is 1.333% which is well within the 3% that's typically acceptable. i found a good calculator for figuring these things here:
http://www.southwire.com/support/voltage-drop-calculator.htm

 

[diffusing]

sunset limited,

thanks for that! exactly what I was looking for.. and more! And it confirmed my calculations weren't as far off as I thought. the 80% rule I had not taken into account (d0h!), which was great to note.. and the 100ft+ voltage drop was a great reminder as well! I'll get my head around this stuff one of these days..

thx again!

 

[Normlfightr]

quick question for you guys

Im useing 1k lumatek ballast

I have to extend my lamp cords from hoods to ballast.

Im extending most of them about 15 feet, some of them 25, for a total run of 40 feet max

will 600v 12/3 s/o cord work?

will 300v 14/3 s/o cord work?

also is there a problem with splicing them together with good wire nuts in a metal junction box?