Electricity supply to the grow room?

Howdy, this is my first post so hoping y’all will help a newbie out. My daughter is building a new house with a dedicated grow room in the basement. We’ll be starting veggie/flower seedlings for outdoors and also a dedicated area for a grow tent. Electrician is wanting to know how much power to wire down there. I’m thinking a 30amp circuit but really have no idea what the average personal consumption demand would need. I’m guessing more than needed is a good thing to allow for expansion.



Welcome to the forum.

Thirty amps should be plenty unless she is planning on a large grow. You can calculate the necessary amps by dividing total watts divided by the 110 voltage.

For instance - 1000 watts requires 1000 watts /110 volts = 9 amps.


You’d only need 30A (240v?) if you were going to run AC?

I run my whole system on two partially-used 15a circuits.

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I just did a 8x10 space that has a 32x72" closet for flower. I ran 20a to it for 3 lights (HLG 260s), a couple fans and exhaust. I have a dedicated 15a outlet for portable AC unit. And another 15a for 3 general purpose outlets.


You need to know what you are going to be running, lights, heat, ac, humidifier, dehumidifier etc. You DON’T want to short yourself, and cause a fire.

So to get the answer is as simple as some calculations…
The electrician should be able to do "service calculations " or I’d rethink paying them to wire my room.

But I always said if I can ever build my own space, I would have at least 2 circuits so if it was me and I thought I needed 30 amps. I would do 2 - 30 amp circuits :man_shrugging:. But I’m the guy that buys a 800w light and never turns it past 75% and over sized exhaust that rarely runs at 50%.

Give yourself twice what you need and you will thank yourself down the road…


Welcome to the forum
I just turned half of my basement into a grow. The first thing I did was make a list of all the necessary equipment and their rated wattage. Also if a new house nows thetime why not have a dedicated panel for the grow only a couple hundred for the extra panel. My home had existing panel and ya can’t just add a bunch of 30 amp breakers. The panel has a limit of how much power it can handle. So I wired all my lighting for 240 volts this cuts the amp draw on the panel roughly in half.
All the quality lights are available in 240v. This made easy to use a 30 amp circuit for each tent or grow space. And this handles fans humidifiers and heaters just fine. I would consider running a dedicated circuit for a mini split ac system. All this depends on what kinda growing going to do. If ya can afford it why not plan for big and if ya don’t use it no harm. Don’t plan on little and run acicuits at max amature growers burn homes down by overtaking the wiring in their homes. We also have smoke detectors wired into our system to shut down power to the grows in event of fire or smoke. I would like a automatic fire suppression system but that’s future project. A home fire brings cops along with fire trucks fyi


I would definitely have multiple outlets for each area. Dedicate one for a timer for lights and a separate one for exhaust, fans and other accessories. If you plan on an AC that should be separate as well.

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I have a 4x4 w all the goodies, lights, fans, heater, humidifier and/or dehumidifier on a dedicated 20amp breaker. Was told by my electrician I could probably run a 2nd tent on the same breaker.

Simple answer is to run two 20 amp circuits. Will cover almost any needs for a long time.
But if its a large unfinished area I would have a 50 amp subpanel installed and you will be set for anything. Adding circuits later will be a simple and cheaper process.

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I just threw a 30 in for the room. I run everything through surge protectors and never tripped it. Ac/2000truew lights/fans xbox sundries…lol.

Only problem with a 30 amp circuit is there are no 30 amp outlets except 220v.
If you are running 12g wire on a 30amp breaker you are asking for trouble.
You can run smaller breakers on bigger wire, but you cannot run bigger breakers on smaller wire.
30 amp requires 10g wire.
30 Amp 110v residential outlets like you need are a code violation.

Spoke with the electrician today, he’s going to install a 50amp subpanel in the unfinished section of the basement. I’ll have plenty of power available with easy access. I’ve got experience from wiring my basement and garage so we’re good to go.
Thanks for all the responses!
I’m sure I’ll be using y’all’s knowledge when it’s time to setup the room.