Growroom Electricity and Wiring

Since there are many, many threads with people asking how to wire this and what wire to use for that, I thought I'd make a thread to have those with some knowledge share it with those that may not have as much. Hopefully we can get this sticky so it can help people in the future.

I will start off with a couple of simple diagrams and charts (not mine ) that may help explain the very basics and hope that others will add diagrams or photos to explain things that weren't covered. I welcome anyone's input so lets get going...

Basic wire color/wire gauge chart:


Wiring size/amperage/voltage chart:


Wiring up a basic outlet: If only one outlet per circuit follow picture to the right.


Wiring up a GFCI outlet:This shows how to wire a GFCI outlet that is NOT protecting the outlet down stream. To protect that one as well, wires going out to the next outlet would use the "LOAD" terminals of the GFCI outlet.


The green grounding screws are located within the metal outlet housing.

I hope this gets the ball rolling. Let's share what we know

,,

That's great Phillthy. Here are some more basics for the noobs:

Watts = Volts (usually 120/240 in the States) x Amps. If a wire ever feels warm to the touch, replace it with one of higher gauge. 120 volt wiring has a hot (black), neutral (white) and ground (green/bare). 240 volt wiring has NO neutral, two hots (red/black) and a ground.

A 240 volt breaker simply takes two slots in your breakerbox, to supply two hot lines. You can install a GFCI circuit breaker if you do not wish to use all GFCI outlets.

Yes. Great idea. Can't believe there is no sticky already on the basics of wiring.

Also, the ampacity ratings on the above charts are already calculated for continuous loads (equipment runs 3 hours or more). You can actually draw up to 1800w on a #14 AWG 15 amp circuit. But for the purpose of grow rooms, you should consider everything to be a continuous load and size accordingly.

Some nifty equations:

P = I x E
E = P / I
I = P / E
E = I x R
R = E / I
I = E / R

P = Watts
E = Voltage
I = Amperage
R = Resistance
d = Drop
K = 12.9 for copper & 21.2 for aluminum
L = Length

CMA values (Circular Mil Area or diameter of individual wire):
Note: I'm not listing 16 or 18 gauge wire because you shouldn't use it period for anything. (unless its the cord on a small fluorescent fixture)

#14 AWG = 4110
#12 AWG = 6530
#10 AWG = 10380
#8 AWG = 16510
#6 AWG = 26240
#4 AWG = 41740
#3 AWG = 52620
#2 AWG = 66360
#1 AWG = 83690
1/0 AWG = 105600
2/0 AWG = 133100
3/0 AWG = 167800
4/0 AWG = 211600

Voltage Drop should also be considered when connecting loads to an existing circuit or running a new circuit.

For Single Phase Residential Service Only:
NOTE - The "2" is to account for both ways. The power goes out to the load and then returns back to the panel. For commercial/industrial 3 phase loads, you would use 1.73 (the square root of 3).

Ed = K x I x L x 2 / CMA

CMA = K x I x L x 2 / Maximum Ed you want

L = CMA x Maximum Ed you want / 2 x K x I

Maximum Ed should never exceed 5% at the farthest/last receptacle. So:
120v circuit would be 120 x .05 = 6v
240v circuit would be 240 x .05 = 12v

Example:

Joe needs to run a new circuit to his bloom room in the attic. He has 1 x 1000w HPS ballast and 1 x 600w ballast @ 120v that will be connected to this circuit. From panel to receptacle will be 250 feet "as the wire travels". (It's a really big house). What is the minimum wire gauge Joe can use and what size breaker should it be connected to?

I = P / E
1600w / 120v = 13.33 amp draw

We know #14 AWG is already off the table by looking at the illustrated wire charts from the first post.

Easier just to use the "CMA =" equation since we are looking for wire size. All standard residential cable is CU (copper). Don't use AL (aluminum) for anything but feeders to a panel.

CMA = K x I x L x 2 / Maximum Ed you want
CMA = 12.9 x 13.33 x 250 x 2 / 6
CMA = 14330

Joe would need #8 AWG to stay under 5% voltage drop!!!! That's some big bucks in cable for 250 foot. Joe would also want to use a 20 amp single pole breaker in the main panel because the total wattage exceeds what is listed in the first post for a 15 amp circuit. You want the wire and the breaker to stay cool. You can't use a 30 amp breaker unless the receptacle is rated for 30 amp (even tho the wire is rated for more than 30 amp).

Pretty sure you also can't fit #8 AWG on a receptacle screw :wink:, so you would want to transition down to #10 or even #12 to attach to the receptacle, but not #14 AWG because it's not rated for that amperage. If you transition down to #12 for the connections, then you can not exceed a 20 amp breaker.

Your whole electrical run is only rated for the weakest link.

Also, always run a ground to everything. Most ballasts will fail to ignite if they are not properly grounded.

Case in point, I had a fluorescent fixture in my basement that was wired with 2 conductor lamp cord (no ground). I had to grab a copper water pipe and then touch the fixture before it would came on... Re-wired it with 3 conductor cord and now it's not an issue. You should always have a ground for safety reasons anyway.

Also, if ever wiring a 240v circuit, just buy 12/2 since you don't need a neutral. But make sure you re-identify the white wire with black or red electrical tape ( at all accessible points) to warn that the white conductor is now a hot.

Oh... This is a big one.

NEVER, EVER "backstab" a receptacle. Those are the little tiny holes that you jam your wire into. I've had more service calls than I can count because of this.

The mechanism that holds the wire in place is spring loaded. Over time, the heating of the wire will wear out those springs and then the connection becomes weak. Once that happens your resistance shoots thru the roof and as resistance increases so does heat. Build up enough of it and you'll completely melt the receptacle and start a fire in the outlet box.

Got some pretty neat/scary pictures of a few of them. If I can find them, I'll post em'.

Your best bet is to buy the "spec grade" receptacles. They have the screws on the side, but slots that you slide the wire into. Then you screw down the terminal and a brass plate sandwiches the wire. They are made way better (and cost a little more too).

Ohms law is good to know but not for sizing circuits using the wattage of an appliance.Always use nameplate amperage rating when sizing circuits.Anything over a 100 ft run could cause voltage drop issues,upsize 1 wiresize per 100ft of circuit.

Yes, good comment. Wattage of bulbs doesn't always jive with what the ballast actually draws. Always go off the nameplate.

That's a pretty decent rule of thumb for wire length/size too. But seeing as how the voltage drop equations are so easy and quick, you should probably figure it out manually before hand just so you know.

Sweet, thanks!

Thank you for your additions! Keep them coming!

Here's one everyone needs to know,stay the fuck away from GFCI breakers!!Unless you want to be resetting them several times a day.When I am forced to use a circuit protected by a GFCI breaker on the job,I cut the "squiggle" line right off.Fuck those pieces of shit.I'm not big on GFI receptacles either unless you're growing in a couple inches of water lol

knifehitz said:

You can install a GFCI circuit breaker if you do not wish to use all GFCI outlets.

Click to expand...

Just a little FYI here - A GFCI receptacle is a breaker, you only need to use one to protect any/all other receptacles that are connected to the "load" wires/side of the GFCI.

PC

What a great thread thank you phillrhy and thank you to every body for the great additions

PharmaCan said:

Just a little FYI here - A GFCI receptacle is a breaker, you only need to use one to protect any/all other receptacles that are connected to the "load" wires/side of the GFCI.

PC

Click to expand...

Eh.... Bad use of terminology. A GFCI receptacle is a receptacle, not a breaker. They provide 2 different functions. But yes, one GFCI can protect an entire run of receptacles. Incoming power to the "line" of the GFCI receptacle and outgoing/downstream power to other receptacles connected to the "load" side of the GFCI receptacle. Yes, the GFCI will say "line" and "load" on the back. The "load" terminals are usually covered up with a yellow sticker when you pull it out of the box.

madpenguin said:

Eh.... Bad use of terminology. A GFCI receptacle is a receptacle, not a breaker. They provide 2 different functions. But yes, one GFCI can protect an entire run of receptacles. Incoming power to the "line" of the GFCI receptacle and outgoing/downstream power to other receptacles connected to the "load" side of the GFCI receptacle. Yes, the GFCI will say "line" and "load" on the back. The "load" terminals are usually covered up with a yellow sticker when you pull it out of the box.

Click to expand...

First of all, I'm not an idiot and I know the difference between a receptacle and a breaker, having installed many thousands of both. The GFCI is/can be, for all intents and purposes, a receptacle/breaker, performing the functions of both. Let's try to keep this thread constructive and not start picking nits just to try to show who is smarter than whom.

PC

PharmaCan said:

First of all, I'm not an idiot and I know the difference between a receptacle and a breaker, having installed many thousands of both.

Click to expand...

I never said or even implied you were an idiot. As to the rest, see below.

Pharmacan said:

The GFCI is/can be, for all intents and purposes, a receptacle/breaker, performing the functions of both.

Click to expand...

Wrong!!!!

A GFCI receptacle absolutely does not provide over current protection. It provides protection against ground faults for your personal safety.

A breaker provides over current protection and nothing more (to prevent fires), unless it happens to be a GFCI breaker, then it provides both.

Pharmacan said:

Let's try to keep this thread constructive and not start picking nits just to try to show who is smarter than whom.

PC

Click to expand...

And there's your issue.

I'm not correcting your statement to be a dick, I'm correcting your statement because many people don't know thing one about electricity. I'm doing it for their benefit, not yours.

If you choose to believe that a GFCI receptacle is the same thing as a breaker, thereby completely bypassing a circuit breaker, that's your choice, however..... I have a serious problem with people spreading misinformation when it could cost them their life or their home.

Basically, your saying it's completely acceptable to have an unfused branch circuit and that's a guaranteed way to burn your house down.

Good job madpenguin like Ricky Rickardo would say "way to splain".A GFI receptacle is certainly not an overcurrent device.Don't be so touchy bro everyone sometimes doesnt splain things too good at times,I'll try to splain.Current travels from the hot to the neutral and is constant,a GFI receptacle senses even the smallest change in current between hot and neutral and trips accordingly.Another words if current starts going through you to ground,a smaller amount will be going through the neutral tripping the circuit.I cant see any reason for one in a grow room myself,except maybe for hydro

And since we are now on the subject, I might as well throw this out in the open before the thread progresses too much farther.

If anyone has any doubts as to how to wire something correctly, then just don't do it.

I have a real problem with some folks around here giving advice as to dismantling ballasts, transformers, variacs and the like. I don't mean to belittle anyone on this forum, but that is way beyond the ability of the average person. I realize a lot of you are technically inclined and can do such things but to give such advice and word it like it's no big deal is morally and ethically wrong. I will not be responsible for the death of any member here so I will never tell someone how to do such things. My answer will, and always will be, "return it". And on a much lesser note, you void your warranty when you do stuff like that. You paid good money for your equipment so just return the damn thing. You shouldn't be expected, as a consumer, to have to service your own electrical equipment.

In fact, I should probably quit posting electrical related topics all together. Electricity is nothing to take lightly. People under estimate residential voltage all the time. The current that a 60w light bulb draws will kill you in a heart beat. Period. If the path crosses your heart, kiss your ass goodbye. Even if it doesn't cross your heart, but you manage to get "hung up", kiss your ass goodbye.

Also, you guys should understand my frame of mind. Yes, I'm an electrician. I love my job. I don't do it for the money. I do it because I thoroughly enjoy working with electricity. I'm an anal son-of-a-bitch and I take longer to do something than your average electrical contractor. Why? Because I do things the right way, not the quick way. If your really good, you can balance both (which I have a hard time doing). Thus, I no longer sub anymore but just work for a company.

So, being the way that I am, The National Electrical Code is scripture to me. Every article in the NEC was put there because someone died. Back in the early 1900's it was a very thin book. Look at how big it is now. So, actually, me telling anyone "unqualified" (yes, it's defined in the NEC) to do work without a permit is morally and ethically wrong. The shit needs to be inspected. If you own your own home, many jurisdictions will allow the home owner to pull a permit. If you live in an apartment, you really should not be doing the work yourself. You make a mistake and you kill everyone in the building. Could you live with yourself if you made a mistake wiring your grow room and your next door neighbors 4 year old daughter burned alive in her bed? Not me.

Or get this.... Say member "kindbud69" received some advice here to swap out the capacitor on his 1000w ballast. "O.K... Sounds easy enough". So kindbud69 goes down in the basement to his grow room to get the ballast. Since he enjoys being in his grow room, he gets a chair and a collapsible TV dinner table and decides to do the work there. Chillin with the plants on a lazy Sunday afternoon, gonna fix my ballast, life is good. Set's the ballast on the table. Takes the housing off. Correctly identifies the capacitor and starts to remove it.

BAM

Kindbud69 is now laying on the floor in cardiac arrest. Too bad joeschmoe589 forgot to mention that the capacitor could very well be charged still. Even more of a shame that kindbud69 had a small hole in his left shoe sole. Worse yet, kindbud69 spilled some water when topping off his res an hour earlier and happened to have his left foot sitting on a wet and grounded surface (concrete floor).

Too bad joeschmoe589 will never know that he indirectly just killed someone. Look at the last line in my sig and ignore the smiley face. It's probably the best thing you can do if you have any hesitation as to how to do something.

Sorry for the book but I take it very seriously and you guys should to. Also, if it's not obvious yet, any and all advice that I give is based upon 120/240v 60hz American electrical systems. If you live in Europe or anywhere else (most of the world) that deals with different voltages or frequencies, then you probably shouldn't be listening to me.

I got nailed on one job so bad it made me goofy fucking with the wiring of my brain.I'm not kidding I found myself putting on two pair of underwear,pouring two glasses of coffee.Locking myself out locking myself in getting lost on the way to the store.I can go on and on.I googled electrical shock psychological problems and there were my symptoms in black and white.I went to a doctor and zoloft saved the day.It was fuckin scary I'll never forget it in my life.And that was after working for 10 years as an electrician lol.It's crazy stuff them electrons

madpenguin said:

I never said or even implied you were an idiot. As to the rest, see below.



Wrong!!!!

A GFCI receptacle absolutely does not provide over current protection. It provides protection against ground faults for your personal safety.

A breaker provides over current protection and nothing more (to prevent fires), unless it happens to be a GFCI breaker, then it provides both.



And there's your issue.

I'm not correcting your statement to be a dick, I'm correcting your statement because many people don't know thing one about electricity. I'm doing it for their benefit, not yours.

If you choose to believe that a GFCI receptacle is the same thing as a breaker, thereby completely bypassing a circuit breaker, that's your choice, however..... I have a serious problem with people spreading misinformation when it could cost them their life or their home.

Basically, your saying it's completely acceptable to have an unfused branch circuit and that's a guaranteed way to burn your house down.

Click to expand...

I never said that a GFCI receptacle provides over-current protection. Obviously that task is performed by the breaker for the circuit.

When an imbalance is detected, the GFCI will break the circuit for any protected receptacles. That's the only point I was trying to make.

But if twisting my words makes you feel smart, go for it. I'll not belabor the point any further.

PC