Setting up a new grow in an Industrial Warehouse, NEED HELP!

Calculating your grow lighting requirements really is just two steps - determine your plant’s lighting needs (watts/square foot), and your plant canopy dimensions.
A common mistake new growers make is measuring the dimensions of the grow room itself.
What you really should be measuring is the footprint of your plant canopy.
For example, if you are growing in a 5’ x 5’ space but your plant canopy only takes up 4’ x 4’, you don’t need a grow light capable of lighting the 5’ x 5’ space - it would be overkill.


Cannabis plants grow best with 20-30 watts of light per square foot. Don’t make the mistake of thinking more is better. Too much light can lead to bleaching and burning your plants.

Let's say you are growing in a 5’ x 5’ grow space. If your plants need 20-30 watts/square foot, and your canopy takes up 4’ x 4’ of that space, you will need 320-480 watts of grow lighting.

I might think of going LED it could save you a bit on electric and give the plants a better spectrum of lighting.

If you are planning on using LED grow lights, there are a few things you need to know about calculating your grow light coverage.
Some manufacturers have two different wattage specifications - displayed wattage and actual wattage (power draw).
Because LED grow lights operate so efficiently, manufacturers will display a wattage equivalent to HPS. For example, the Gavita LED 1700e is 646 actual watts, but is equivalent to a 1,000 watt HPS.
So, if your 5’ x 5’ growing space requires 320-480 watts of grow lighting, and you choose the LED route, make sure your LED light features an actual wattage of between 320-480.

Now that you know how many total watts of grow lighting you need, you can decide how many lights you will use.
Our grow light setup post will help you with this step, as there are plenty of possibilities.
With this 5’ x 5’ grow example, the space is big enough where two grow lights could be an option.
However, it would make more sense to use one large grow light.
The number of grow lights your room will need really depends on the size of it.
Grow lights have gotten more and more powerful as technology continues to advance, but at a certain point, 2 lights can cover an area more effectively than 1.
There are also grow rooms that will need even more lights. For example, an 8’ x 8’ grow room would likely need 4 grow lights, and a 10’ x 20’ room could need up to 8 lights.

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Courtesy of Hydrobuilder..

Renfro said:

The only thing 3 phase power does better than single phase is running large motor loads. Thats it. Thats the only reason to have three phase power unless you are a distribution network.

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Bro from an industrial electrician, I am very impressed with your knowledge. You in the trades?

Kingsblend420 said:

Bro from an industrial electrician, I am very impressed with your knowledge. You in the trades?

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I did work as a sparky.

The thing that most don't realize is that 277v lighting is a phase to neutral on a 480v service. Three phase power is generally installed with a transformer that has a neutral thats only rated for 15%of the kva. It is only intended to serve lighting loads in an industrial setting where most of the service power is for three phase motor loads.

So pulling in a bunch of amps of three phase to run mostly lighting is just something thats not generally done.

Renfro said:

I did work as a sparky.

The thing that most don't realize is that 277v lighting is a phase to neutral on a 480v service. Three phase power is generally installed with a transformer that has a neutral thats only rated for 15%of the kva. It is only intended to serve lighting loads in an industrial setting where most of the service power is for three phase motor loads.

So pulling in a bunch of amps of three phase to run mostly lighting is just something thats not generally done.

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You're spot on sparky!

Renfro said:

You are incorrect with your math.

With split phase or single phase power, when we use both hot legs we multiply x 2 the leg voltage because they are 180 degrees apart. So two 120v legs make for 240 volts.

With three phase power where phases are 120 degrees apart, we multiply the leg voltage by the sqrt of 3 (1.72). So using 277 volt legs means we get 480 volts and not 554 volts.

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ah yes probably different in usa. i already heard that story of 240v made with 2 hot legs of 120v
i was a bad advise on this one

here in europe we have 240volt with 1 hot and 1 neutral. sometimes its 220, sometimes 230v ...
and if you have a house with 3 phase, the voltage between 2 of these phase give 400v
if you only want to have 240v, just need to use one of those hot wire and a neutral
thats called tri-polar

BIGBALLSJOE said:

ah yes probably different in usa. i already heard that story of 240v made with 2 hot legs of 120v
i was a bad advise on this one

here in europe we have 240volt with 1 hot and 1 neutral. sometimes its 220, sometimes 230v ...
and if you have a house with 3 phase, the voltage between 2 of these phase give 400v
if you only want to have 240v, just need to use one of those hot wire and a neutral
thats called tri-polar

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Three phase is summed using the square root of 3. Just don't worry about it and let your sparky tell you the best way to go.

If running 3 phase - you may want to consider a power conditioner.
Otherwise your ballasts may not stay happy. Then again, digital ballasts probably eliminate dirty power issues.

spek9 said:

Cutting Amps and upping volts doesn't 'save' anything. Here's an example:

120V x 10A = 1200W

240V x 5A = 1200W

No matter how you slice the amperage, you're still burning the same amount of electricity. The benefit to less current is smaller diameter wire.

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I know that but iam not looking to save on wattage just trying to free up amperage i might need later on.
For example i really wanted to get 1200 amps service put in.But according to my electrician when you hit 1000 amps and up things get crazy expensive as certain types of transformers/parts are needed.If i go the 3 phase rout i will be saving amperage overall even though he said 800 amps should be more than plenty for a 4500 sq ft of future grow using DE lighting.

For the existing 1500 sq ft i plan on running 46k to 52k of lighting
4x5 ton ac
2x255 pint dehuy
1x155 pint dehuy
2 large humidifiers
2 small humidifiers
half a dozen scrubbers anywhere from 10"-14"
30 walls fans
whatever pumps,etc needed.
This would be for a 400 amp service.But iam thinking i can do the ac's and 30-36k flowering lights in 3 phase setup which should free up around 25 amps at least vs standard service.

EDIT:I should've probably started a thread hehe