It seems like so often for our grows we are shoved into tight places, where other "normal" household activities don't take place. This is often the basement, water heater closet or other less inviting location where we can grow in "peace".

Many of these locations also pose some risks, as there are electrical lines and water in close proximity to one another, not counting the HIGH current that runs through HID ballasts (or any ballast).

Some care and thought needs to go into the SAFETY of where you plan to raise your stash. Don't pick a spot that is high in humidity (active laundry rooms, etc).

Let's start with ELECTRICAL safety.

For this article I'll stick with 120V AC as the primary power source.

If you are using HID lamps (HPS or MH), what is your "Amp Budget"? What I mean is, how many amps of power are available ONLY to the circuits in your grow area? Whatever that number is, do not plan to use more than 75% of the available amperage, as exceeding that can result in inconvenient power outages to your lights due to blowing a circuit breaker (or worse). Homes with older wiring should always get a close inspection before hooking up ANY high-power electrical equipment.

Circuit Breakers are made of varying sizes and configurations. The ones for your breaker box are designed to work with the in-wall wiring. Most homes are wired (today) with 12/2, meaning 2 wires (plus ground) that are 12 ga. wires. This wire can handle 20 amps safely, but don't ask it to carry 30! If you have a 20 amp. breaker and 12/2 wiring, you are at your maximum capacity for that circuit. If you want to increase the available amperage to your outlet, you can replace the 12/2 with 10/2 Romex wire and THEN replace the circuit breaker with the proper 30 amp. breaker for your circuit box. To ask smaller wire (12/2) to handle 30 amps is a dangerous venture, as FIRE can result, costing you much more than just the few plants you had vegging!


How to calculate your "Amp Budget"

First, gather ALL of the electrical devices that will be operating in your grow room. This would essentially be all of the devices that will be operating while the lights are on.

Take each product (fan, ballast, light) and look at the manufacturers specifications. How many AMPS does it draw?

I'll use my Veg room as an example:

1000 HPS Ballast: 9.6 amps.
Circulation Fan: 1 amp.
Intake air fan (when operating) 1.5 amps. (liberal estimate if you don't have the ppwk)
Exhaust Fan for air-cooled fixture: 2 amps. max.

Total: 14.1 amps on a 20 amp circuit.

I would still be comfortable at 15 amps total, but beyond that the circuit can "pop" at any time, especially if it is an older breaker.

Some breaker boxes have spaces for additional breakers to be ADDED to the breaker box. This is an operation only for qualified individuals! Don't be messing about in that breaker box unless you know exactly what you are doing!!!

Before you begin your grow, you can have an electrician come in and wire in another breaker for you. To make it easier, you can run the wire to the grow area externally (in flex or rigid conduit) and leave the end for him/her to hook up to the breaker. I would suggest that if you are going to spend the cash to have this done, be sure to use the 10/2 wire and (if available at the box) make the breaker a 30 amp. for insured safety, but DO NOT overtax the main lines feeding your home or space.

It is standard for homes to be fed with a 100 amp. service, and most garages that have a separate breaker box are generally wired for 100 amps, BUT NOT ALWAYS. For example, if you have 100 amp. service to your garage, and there are already 3 of the 20 amp. breakers there then (hopefully if there is an open space) you still can add the 20 or 30 amp. dedicated grow room circuit. Be sure to find out which outlets are powered by which breaker and label them accordingly so you know where the power you are drawing for that extra, un-budgeted device is coming from so you don't go blowing the circuits.

Routing of Electrical and other wires/cables:

ALL electrical cables should be wired in from ABOVE the devices they will be operating. This way, you are assured that no water can come in contact with the wires or connections. It is NEVER a good idea to lay a cord along the ground or beside plants where it can come in contact with water. Water and Electricity DON’T MIX! Not to mention you could get lit-up, permanently and in a fashion you would not want to imagine!

Use conduit whenever possible to enclose exposed wiring, including junctions of extension cables. It only takes one little “spill” while you are watering your plants to cause a catastrophic electrical short in a line.

This becomes more difficult when a hydro grow is in process, as air pumps and water pumps don’t generally have 10’ power cords attached. In this case I would mount a small shelf at a level that is above your light fixture and big enough to hold the air pumps, then run power UP to that shelf and then only the air lines need to run down to the buckets/bins. It can reduce your PSI at the airstone some small % by the longer run, but well worth the increased safety factor!

I’ve routed my air lines inside of a piece of 2” PVC conduit for a couple of reasons. One, I am not very coordinated (disease took my balance) so I need to be careful around stuff I could knock over or grab for if I am losing balance. You can often find lengths of this used (or new) PVC pipe in construction debris piles, and the site manager will generally tell you to help yourself to the unwanted left-overs IF YOU ASK FIRST.

Keeping all lines up high, both electrical and air, insure that you will be worry free about your grow having (electrical) issues while you are home, asleep or away.

Hopefully this will give us a good start!

Be safe and Happy Budding!

ISO

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WoW ISO, what a great post, very helpful.
I hit the scales and gave ya some rep for that one!
Peace my friend

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Ex-owner
Retired

This is just awesome Iso. We are building a more permanent spot for the grow than the closet it is in now and this helps a lot. We are running new power lines in our old house into this space and beyond, into the garage for power tools. My quest has been how to estimate the ampage we will need so we can do all this before we seal up the cielings and feel safe and secure with the electrial things we will be using. And also add to it as the "Bells and whistles" are introduced. Our home is older so we know we have to add, just not the totals needed. This helps so very very much. Thank you,

Life,
jangel

Very helpful post, well explained and easy to understand, thank you. I’m putting together my grow box and was trying to figure out how much power I had to work with. Now I know.

Thanks again,

OG

Howdy OG,

Glad it came in handy for ya. Hell, I wrote that nearly a year ago and had to re-read it just to remember what the post was about.

How large a box are you planning on using?

ISO

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I've been thinking about the size for a while now. I looked at the size of some the commercial "all-in-one" units 6'x36"x24" and thought about building it to those specs. But I think I'm going to build it 6'x24"x24". It will provide enough space for my needs. Plus I can put it all together, sides, top and bottom using two pieces of 4x8 plywood.

I think this could be a sticky or in FAQ, nice post!

Really good post. I am currently remodeling my flowering room and this post answerd a few ? I had and gave me some great/safe ideas going from 2- 400w hps to 5 400w hps lights.
Thanks/