Growroom Electricity and Wiring

[rives]

If you have a place to splice into the run, that would work. You need to make sure and do the connections well, ground the junction box if you use a metal one, and you probably won't be able to use your dryer while the lights are on. The wiring would get a little trickier (but not by much), but you could bring the run feeding your dryer to the relay, power the dryer off of the normally closed contacts and the small sub-panel with the normally open contacts. That way the dryer would be interlocked from running if the lights were on.

Thanks, I'm happy to help wherever I can.

 

[draztik]

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[rives]

No, what I was talking about was taking the feed to the common terminal for the NO/NC contacts, the sub-panel would attach to the NO, and the dryer to the NC. That way the sub would be powered up when the relay was energized and the dryer would be powered when the relay was off.

If you only plan on a single light, it might not be an issue. You would need to see what the actual draw was on the dryer to see if the circuit could handle both loads at once. However, the voltage sag from the dryer starting might cause your lamp to drop out and restart even if there was enough current to run both simultaneously.

 

[draztik]

OK thanks

 

[draztik]

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[rives]

I have figured out what breakers are doing what. The breaker that was labeled dryer is actually for an A/C that won't be used until summer. It's a 20 Amp 240V breaker. Like I said earlier I am going to build my own controller based on that DIY I posted earlier. I am only going to run one 1000Watt light. When I build my controller should I get a sub panel and add a smaller breaker before the light controller since I'm only running one light? And can I use 12-3 and have both 240V outlet and 120V outlet on the light controller?

A 20-amp breaker feeding the light controller would be fine without more downstream protection. If you are going to use the dryer's 30-amp feed, then more protection downstream would be required. You need to look at what the lightest-rated component in the circuit is and make sure that there is appropriate protection ahead of it. 15 amp receptacles can be run on a 20 amp circuit as long as there is more than one receptacle on the circuit.

Some people confuse 12/2 with ground and 12/3. 12/2 w/grnd has 3 wires in it - black, white, and bare. 12/3 with ground (red, black, white, bare) will work fine for getting you a 120/240 feed to a 20 amp rated controller.

 

[draztik]

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[sunset limited]

yo rives—

so i'm trying to idiot proof my grow and i've got it in my feeble little mind that you're the guy who can help.

i veg in an aero system i designed and built out of 5" vinyl fence posts and 3/4" schedule 40 with a bunch of spray nozzles in it. it's got a couple inline filters in it (one for each pump) that keep sediment and vegetable matter from clogging the sprayers. i've got to turn off the pumps and clean the filters every couple of days. for some reason, in spite of how damn meticulous i am about so many other things, i have the worst habit of forgetting to turn the pumps back on. i've tried writing myself notes on the door, ritualizing my routine, getting my helper to remind me, etc... about once every 6 weeks though, i just plain forget to turn the damn thing back on. i need to automate this damn thing before i kill a grow and really start to hate myself.

what i want is a knob i can turn or a switch i can throw that will cut off the pumps for a time and then turn them back on automatically. i've seen the mechanical timer switches they have on hot tubs and heat lamps in hotel bathrooms. something like that would do fine, but those open the circuit when the timer reaches zero. i need it to go the other way around. is there such an animal? if not, can i modify something that's already out there to do the trick?

for what it's worth, i do care a whole fucking lot about not starting fires, but no building inspector will be dropping by anytime soon, so feel free to interpret the code loosely if that helps with the project.

i'm curious to hear what you've got for me sir.

 

[rives]

There are a bunch of ways that you could accomplish it. Unfortunately, time-delay relays are pretty expensive and would require a number of other components to make it work. By the time you got all of that gathered up, one of the little programmable relays would probably be cheaper.

I think that the easiest way for you to do it would be to take one of the spring-wound timers like you are talking about (bathroom fans are another one that use them, both mechanical or electronic models), and use another relay to flip the logic. If you go through the normally closed contacts of the relay to power your pump and drive the relay coil with the above timer, it should get you what you want.

 

[SmokinErb]

Need a little direction in installing a small subpanel so I can run AC this summer.

My main breaker box is full, the sub panel has 2 slots for breakers so...

Do I install a 30a breaker in place of the 20a in the main box, and run a 10/2 wire to the sub panel, then install two 15a breakers - hook up the wiring from the circut already there, and then run a new one with the other 15a?

Or, do I leave the current circuit there alone and wiring up the sub panel to the main some other way without using a breaker in the main panel for it?

 

[rives]

SmokinErb, I'm not sure that I got the full picture.

If you are saying that your sub is fed from the main panel with a 20a breaker and you don't have enough power for your a/c, then yes, you can upsize the wire to #10 and change the 20a to a 30a breaker. That doesn't sound like a lot of additional power to me, but it depends on your existing load and the size of the air conditioner.

Any feed from the main panel needs to be protected with a circuit breaker. It isn't required to have a main breaker in the sub, but I prefer to have one. The wire has to be protected at the feed end, though.

 

[sunset limited]

There are a bunch of ways that you could accomplish it. Unfortunately, time-delay relays are pretty expensive and would require a number of other components to make it work. By the time you got all of that gathered up, one of the little programmable relays would probably be cheaper.

I think that the easiest way for you to do it would be to take one of the spring-wound timers like you are talking about (bathroom fans are another one that use them, both mechanical or electronic models), and use another relay to flip the logic. If you go through the normally closed contacts of the relay to power your pump and drive the relay coil with the above timer, it should get you what you want.

seeing as i still have no clue how smart relays work and nobody can recommend a good book on the subject, it looks like i'm going to buy two of those mechanical jobs. one to break open and another to fix up. i'll send along the pictures if (read: when) i get stuck and need your help again.

 

[SmokinErb]

SmokinErb, I'm not sure that I got the full picture.

If you are saying that your sub is fed from the main panel with a 20a breaker and you don't have enough power for your a/c, then yes, you can upsize the wire to #10 and change the 20a to a 30a breaker. That doesn't sound like a lot of additional power to me, but it depends on your existing load and the size of the air conditioner.

Any feed from the main panel needs to be protected with a circuit breaker. It isn't required to have a main breaker in the sub, but I prefer to have one. The wire has to be protected at the feed end, though.

Okay, I'm really bad at explaining electrical stuff, so I'll try again.

The breaker in the box that I have drawn a rectangle around is the one that's currently in place. As you can see, there are no more additional slots for breakers.

So the idea I had was, since I only need one additional circuit, is to add a small sub-panel just on top of the main panel, as shown with my crude drawing.

The two additional rectangles in the larger one are the two breakers the small sub panels hold. My plan was to replace the breaker in the main panel with a 30a (size of sub panel), place two 15a breakers in the sub panel.

The circuit currently in place would be hooked up to one of the 15a breakers, and then I'd run the additional 15a to the window for the AC unit.

Could I run two 20a from the 30a sub? Worst that can happen is the 30a breaker would trip? I doubt I'd ever exceed 30a total draw. 2200w of heavy equipment (800w HPS + 324w T5 + 1000-1100w AC/650w heat) plus some fans.

I may look for a larger panel that can hold 3-4 circuits, but I'm concerned about finding wire to run TO the sub panel. I know 14-2 is for 15a, 12-2 for 20a, 10-2 for 30a....

But 70a? 50a? 125a?

The reason I picked a 30A panel, is because it's the only one I can figure out how to install.

http://www.lowes.com/pd_86175-1318-LC004NSU_4294722482__?productId=3180815&Ns=p_product_price|0

I just don't get how you'd install a 125a panel to a a box like mine that's probably only 100a itself? Or even a 70a, because I've never seen a 70a single pole breaker that'll fit in my box.

I suppose I could always get a double pole, and relocate the #1 slot breaker to the sub panel as well....

Plus I need to find some scrap romex. I can't be buying large lengths of whatever I need to run, 6-2? for a 70a breaker. Especially when I only need like 2 ft.


Edit: Also, what's the difference between a box like the one I linked above (8 circuit, 4 slot) and this one (2 circuit, 4 slot) http://www.lowes.com/pd_72191-296-QO24L70RBCP_4294722482__?productId=3364890&Ns=p_product_price|0

 

[SmokinErb]

Okay, so I've been looking around and here's where I'm at - I'm going to opt for a 4 space box instead of a cheaper 2 space box.

70a, 2 circuit 4 space main lug

60a breaker to replace the two single pole breakers in the main box, wired to the main on the panel above:

Then I'd just install 15a circuits in each slot, hook up the 2 circuits for the lights/wall fixtures in the garage and then wire up 1 or 2 new ones for the grow.


Basically:

 

[rives]

It looks as though you have answered your own questions - the equipment in your last post would work well.

Regarding your space/circuit question, "spaces" are for conventional, full-size breakers. Most manufacturers build "wafer" or 1/2-size breakers, so that is why the circuits are normally double the spaces. Some panels will only fit the wafer breakers in certain spots, so the number can sometimes be different than 1:2. The Lowes advertisement for the Square D panel is incorrectly worded. If you go to other sites with that part number, they will describe the panel as "2-space, 4-circuits".

Yes, you can run (2) 20a circuits from a sub that is fed with 30a. If both are loaded heavily, the 30a breaker in the main will trip.

If there is a question in there that I am missing, holler back.

 

[SmokinErb]

Thanks! I was just learning about Tandem breakers when you replied.

I think the first thing I should do is look and see if I can't convert the two current single-pole circuits into tandems and just run some new wire if possible? it would just mean hooking up the current wire to one part of a tandem breaker, and then a new wire to the other part, I believe? Assuming my box can take tandem breakers.

and then if not, get a cheaper box with only 2 slots that can hold tandem breakers and wire it up that way? Looking for the cheapest way to do this so long as its done properly.

Edit: Tandem breakers fit my box, thanks for pointing me in the right direction. Saved me a few bucks too!

 

[farmhouse cat]

Is it possible???????

I pulled out the 1k ballast plug from the light controller after it was already on (i saw a spark) (to do some maintainence)

Now... when lights on comes.. the bulb or ballast doesn't fire up? (unless i pull it out and then replug it)

Could there have been an arc on the plug creating a condition where the connection isn't made anymore?

If so...will wirebrushing the plug do the job?


stonehead.

 

[rives]

Is it possible???????

I pulled out the 1k ballast plug from the light controller after it was already on (i saw a spark) (to do some maintainence)

Now... when lights on comes.. the bulb or ballast doesn't fire up? (unless i pull it out and then replug it)

Could there have been an arc on the plug creating a condition where the connection isn't made anymore?

If so...will wirebrushing the plug do the job?

stonehead.

I wouldn't hold out a lot of hope for wirebrushing the plug. If there was a loose connection in the plug to start with, pulling it under power may have blown it clear.

Are you saying that the light does work if you unplug and plug it back in after the first failure? The cord may have a break in it a couple of inches behind the plug, and a different orientation brings the break back into contact.

Is this an electronic or magnetic ballast?

 

[farmhouse cat]

Thanks Rives.. yea...nothing happends at lights on. But if i pull the plug out and then reinsert it it fires up the digital ballast.

One light on this same controller fires up in another room, so i know the timer is working. It just the 2 that i pulled out the other day (while on).

 

[ak-51]

To monitor the performance of my ballasts and lights, I would like an in-line ammeter that is always running. Ideally this would be like a 220/240 volt version of the Kill-A-Watt. Unfortunately this product does not exist, and even if it did exist I have reservations about leaving such a product plugged in with so much current running through it all the time. I think I remember reading some horror story somewhere about somebody's Kill-A-Watt melting.

How could I go about making such a device? I have one 30a circuit that has 3 Nema 6-15 outlets on it. I wired this myself and I am confident that I can wire something in-line on that safely, provided that that components themselves are safe.