question on wiring a 240v system

[BreezeEazy]

I'm having a hell of a time trying to figure all this crap out. My electrician for this upgrade has cancer and is busy with all that so I'm trying to do as much by myself as possible. Ironic though that he is holding my progress up at the moment and becoming my patient in need at the same time.

Anyways I got a panel specifically for my new grow. It has 5 breakers in it for all my 120v stuff and currently 3 x 30 amp breakers for my 240v stuff. My current goal is to get 4 lights on one breaker max. So 30 amp break runs to an outlet via 12-3 romex. Here is where it gets frustrating. I want to try and get a 240v duplex outlet (15a) or worse case a single outlet (20a). I need to get 4 lights on one breaker and I'm not sure specifically how to do it. I have gavita pro 1000s which has a 5 amp draw, so on the duplex it would be a 10a draw on a 15a outlet, and on a single outlet it would be 5a draw on a 20a outlet leaving me buffer space for spikes. How can I attach a second box or 3 more boxes to the first one so that I can run 4 lights off one breaker?

 

[rives]

Better back up. You do not run 12/3 on a 30 amp breaker. #12 is good for 20 amps at most, and many people use it for 15 amp circuits (myself included). By code, unless you are running a specially listed breaker (very rare), you are limited to 80% of the breaker rating for continuous loads, which are considered any load that runs in excess of 3 hours. So a 15 amp breaker should feed 12 amps of lighting at most, and a 20 amp breaker can feed 16 amps of lighting maximum.

When sizing components, everything downstream from the breaker needs to be rated for the same amperage as the breaker (or more) so that the breaker will trip before anything downstream is destroyed. If you use a 30 amp breaker, the minimum wire size that you can use is #10, and the receptacles have to be rated for at least 30 amps - you cannot use multiple 15 amp receptacles and have them"add up" to 30 amps.

If you "have to" run (4) 1K lights on a single circuit, you will need to use a 30a breaker (24 amps available by the 80% rule), minimum #10 wire, and 30 amp receptacles and cordsets. Are you limited for space in the panel or why are you putting this restriction on yourself? To keep the prices of components down and stick with easily sourced materials, I would run 2 lights per 15 amp breaker, with #12 wire and 15a 240v receptacles.

 

[BreezeEazy]

To keep the prices of components down and stick with easily sourced materials, I would run 2 lights per 15 amp breaker, with #12 wire and 15a 240v receptacles.

Sigh.. this is turning into a nightmare. I see what you are saying. So take the 30a breakers back for 15a double pole breakers. Run one line (12-3) from the breaker to the 15a outlet. Now, can that be a 15a duplex outlet? And where would a timer fit into this?

 

[rives]

Yes, that could be a duplex outlet, or a couple of duplex outlets if that makes it handier to plug in your gear - you just have to limit what you plug in to that circuit.

The timer can either be located after the receptacle or before. You could run direct from the panel to a timer, say an Intermatic T-104, and have the receptacle(s) set below the timer, or set the timer up with a cord that plugs into the receptacle and then has it's own, switched, receptacle for the ballast power.

It really shouldn't be a nightmare if you have some basic mechanical aptitude and some tools. We'll get you through it.

 

[packerfan79]

Just simplify it dude. You can get a 4 light controller on Amazon for around 100 bucks. 30 amps will fit a 4 light controller 4 lights on one timer no trying to synch 4 timers. It's only 3 wires

 

[Miijade]

Just set up a 8k grow and this is what i used. Saved me a bout $1300 going with this unit. Dxhydro.com

 

[Redbuddz]

BreezeE are you saying you will be using 12 - 1000watt lamps?

 

[cody2white]

All I know is when Rives chimes in I listen lol you are awesome sir, keep on saving lifes.

 

[Jhhnn]

All I know is when Rives chimes in I listen lol you are awesome sir, keep on saving lifes.

Indeed. I have a question of my own-would 20A breakers & receptacles be acceptable with #12 wire in a 240V circuit?

I think it would be, but I do have enough sense to ask.

And I think I just figured it out. As Rives offers, the cordsets need to have the same rating as the breaker or higher, and 15 amp cordsets are more common.

 

[BreezeEazy]

BreezeE are you saying you will be using 12 - 1000watt lamps?

The max that will ever be in my basement will be 9x1000s. I got 3 that will be running in the flower room and 2 600s that I want to run on 240v for veg from the start. But I'm designing this for the MAX that I can run just to get it out to of the way now because who doesn't want the max?

All I know is when Rives chimes in I listen lol you are awesome sir, keep on saving lifes.

I should have just come straight to you guys first me thinks lol

@ rives

So now it sounds like it would be easier to run a 30a breaker? I spent $80 on 150ft of 12-3. I'll junk it and replace with 10-2 wire. So 30a breaker -> 10-2 wire -> hard wire to a timer -> double gang box with 2 duplex outlets. 1 timer like you showed can work for 4x1000s. Is this right now? lol

 

[rives]

Thanks Cody & Jhhnn, I appreciate your confidence in me!

Indeed. I have a question of my own-would 20A breakers & receptacles be acceptable with #12 wire in a 240V circuit?

I think it would be, but I do have enough sense to ask.

And I think I just figured it out. As Rives offers, the cordsets need to have the same rating as the breaker or higher, and 15 amp cordsets are more common.

There are some odd provisions that go back and forth between 15 and 20 amp circuits on both 120 & 240v circuits. In answer to your question, yes, #12 wire is fine for a 20 amp, 240v circuit. 15 amp receptacles can be used on a 20 amp circuit providing that there is more than one of them on the circuit. If you look at the Nema plug configurations, a 15 amp plug (either 5-15P or 6-15P) will work in a 20a receptacle (5-15R or 6-15R), but the reverse does not. Most cordsets are short enough that the wire size is nearly irrelevant as long as the plug/receptacle will fit together. The shorter the wire, the higher the amperage it can carry without overheating and destroying the insulation. This exception doesn't apply to extension cords or long, hard-wired power cords, but explains why some device cords can be as small as they are. For instance, many PC cordsets are only 18 gauge or smaller, but they are legal on either 15a or 20a circuits. Clear as mud?

So now it sounds like it would be easier to run a 30a breaker? I spent $80 on 150ft of 12-3. I'll junk it and replace with 10-2 wire. So 30a breaker -> 10-2 wire -> hard wire to a timer -> double gang box with 2 duplex outlets. 1 timer like you showed can work for 4x1000s. Is this right now? lol

There are many ways that you could do this, you just need to figure out what will give you the most flexibility for the future and meet all of your needs. Incidentally, that price for wire is pretty damn high - I think that is what a full 250' roll currently is at Home Depot. A full roll is always going to be cheaper than the bulk wire cut-to-length.

The problem with the 30a circuit as you are describing it is going to be the receptacles/cordsets. They either need to be sized for 30a or have further protection set (lower amperage breakers/fuses) - the above mentioned relationship between 15a & 20a circuits does not apply to 30a circuits. If the arrangement works for you, an easy way to accomplish what you are describing would be to add a small sub-panel after the timer. The Intermatic T-series timers are rated for up to 40 amps. You could use up to a 40a breaker (that would require #8 wire) to feed the timer, and then use the timer output to feed the sub-panel. You could then set a number of 15a double pole breakers in the sub and have the appropriate protection for 15a components downstream. A small main-lug only sub-panel is cheap, usually under $40 or so, and this would give you excellent protection.

A couple things to bear in mind with this arrangement would be that all of the lights powered by the sub-panel are going to operate at the same time, so you cannot do part veg/part flower with a single timer/sub. Also, the Intermatics are targeted at the water heater market, and the timing resolution is pretty coarse but highly repeatable. You attach "trippers" to a motorized disc to actuate the contacts, so if you want the lights to switch at 9:00, you might get 8:55 or 9:05. It doesn't make any difference to the plants, but some people don't like it. It's also possible to build up a power relay controlled by a digital timer so that you get the timing resolution that digital technology makes available, and if you have frequent power outages, then you can get a battery-backed timer so that your settings don't shift.

 

[BreezeEazy]

The problem with the 30a circuit as you are describing it is going to be the receptacles/cordsets. They either need to be sized for 30a or have further protection set (lower amperage breakers/fuses) - the above mentioned relationship between 15a & 20a circuits does not apply to 30a circuits. If the arrangement works for you, an easy way to accomplish what you are describing would be to add a small sub-panel after the timer. The Intermatic T-series timers are rated for up to 40 amps. You could use up to a 40a breaker (that would require #8 wire) to feed the timer, and then use the timer output to feed the sub-panel. You could then set a number of 15a double pole breakers in the sub and have the appropriate protection for 15a components downstream. A small main-lug only sub-panel is cheap, usually under $40 or so, and this would give you excellent protection.

A couple things to bear in mind with this arrangement would be that all of the lights powered by the sub-panel are going to operate at the same time, so you cannot do part veg/part flower with a single timer/sub. Also, the Intermatics are targeted at the water heater market, and the timing resolution is pretty coarse but highly repeatable. You attach "trippers" to a motorized disc to actuate the contacts, so if you want the lights to switch at 9:00, you might get 8:55 or 9:05. It doesn't make any difference to the plants, but some people don't like it. It's also possible to build up a power relay controlled by a digital timer so that you get the timing resolution that digital technology makes available, and if you have frequent power outages, then you can get a battery-backed timer so that your settings don't shift.

Well ya see, the thing is, I'm adding two rooms. I have a veg room and a flower room. So it could be easier to run a 10-2 wire (3 of them) now. Each one connected to a timer. The veg room can be on its own timer for obvious reason and the flower room will have two timers in it so I don't have all the lights coming on at once. My panel is on the opposite side of the basement so that one can access it without going into any of the grow rooms. I don't mind this concept for now. It is only a 2 year kind of thing and then I'm hoping to have something a little more permanent (I want to move out of state). At that point I'll want to run a main line and a sub panel more like you are talking about. The gavita has a NEMA 6-15 plug. I'm currently being told that running the 10-2 wire to the timer and then to the double gang box would be more of what I want. Dude says use 10-2 wire from the panel, to the timer, and keep using it to connect to the outlets which can be a 20a or a 15a duplex outlet.

To make matters worse, I'm a visual learner. I learn fast but if I can't see it, I start to struggle. People are giving me multiple options and its confusing me But I definitely appreciate the fact you are trying to save my life and help me.

 

[rives]

Make sure that you use 10/2 with ground, not plain 10/2. #10 wire is larger than what you need for a 15-20a circuit unless it is a very long distance from the source panel to where your gear is, and it is going to be difficult to fit #10 wire into the receptacles. If you want to go this route, I would suggest #10 feeding the timer and then parallel a couple of #12's out of the timer, one to each receptacle. Other than distance, there is no benefit to running #10 wire if you stick with the 15 or 20 amp protection that the duplex receptacles are going to require, though.

 

[BreezeEazy]

Make sure that you use 10/2 with ground, not plain 10/2. #10 wire is larger than what you need for a 15-20a circuit unless it is a very long distance from the source panel to where your gear is, and it is going to be difficult to fit #10 wire into the receptacles. If you want to go this route, I would suggest #10 feeding the timer and then parallel a couple of #12's out of the timer, one to each receptacle. Other than distance, there is no benefit to running #10 wire if you stick with the 15 or 20 amp protection that the duplex receptacles are going to require, though.

Each line would need to run 20-30 feet roughly to get to a timer. I can mount a timer next to the outlets. that distance shouldn't be horrible right?

 

[rives]

That distance is no problem for #12.

 

[BreezeEazy]

Okay so I'll grab 15a outlet so that they match up with the 15a nema plug and parallel 2 outlets to one timer giving me a max of 4 lights on one timer. I should have no safety issues right? and make sure I get a #10 wire with ground and 12-2 wire for the parallel wiring. That would be probably the best way to do it for my situation.

 

[rives]

Well, that will work but not for 4 lights - remember, the 80% rule limits you to 12a on a 15a breaker and 16a on a 20a breaker. At 5a per light.....

 

[theother]

Better back up. You do not run 12/3 on a 30 amp breaker. #12 is good for 20 amps at most, and many people use it for 15 amp circuits (myself included). By code, unless you are running a specially listed breaker (very rare), you are limited to 80% of the breaker rating for continuous loads, which are considered any load that runs in excess of 3 hours. So a 15 amp breaker should feed 12 amps of lighting at most, and a 20 amp breaker can feed 16 amps of lighting maximum.

When sizing components, everything downstream from the breaker needs to be rated for the same amperage as the breaker (or more) so that the breaker will trip before anything downstream is destroyed. If you use a 30 amp breaker, the minimum wire size that you can use is #10, and the receptacles have to be rated for at least 30 amps - you cannot use multiple 15 amp receptacles and have them"add up" to 30 amps.

If you "have to" run (4) 1K lights on a single circuit, you will need to use a 30a breaker (24 amps available by the 80% rule), minimum #10 wire, and 30 amp receptacles and cordsets. Are you limited for space in the panel or why are you putting this restriction on yourself? To keep the prices of components down and stick with easily sourced materials, I would run 2 lights per 15 amp breaker, with #12 wire and 15a 240v receptacles.

Just wanted to ask a quick question here, so you are saying that all plugs on a 30 amp 230v breaker need to be 30 amps? Whenever I see 30 amp receptacles they tend to be those shop twist lock kind not the normal kind that ballasts plug into. I have always seen people set up 30 amp breaker, spa timer, series of 4-5 20 amp 230 volt receptacles like these http://www.homedepot.com/p/Cooper-W...le-with-Side-Wiring-White-1876W-BOX/203492426

You do make a good point that I had never thought of, in the unlikely event that somehow the normally 5 amp load spiked to 25 amps or something it could start a fire without tripping the breaker. Please point me in the direction of 30 amp outlets.

 

[rives]

Yes, if you are running a 30a breaker, all downstream components must be rated at 30a or greater to be code compliant.

30a/250v twist-locks would work, but they are usually more expensive and most of our applications don't require that level of strain resistance. 30a straight-blade plugs are both huge and expensive (think dryer plug/receptacle) - the size is indicative of the amount of power available there in an instant. It is usually cheaper and easier to get the protection in on the front end (breakers or fusing) than to build the system to withstand that level of power. Remember, there is a time-current curve for a breaker to react - a brand new breaker that meets all factory specifications can take several minutes to react to a substantial overload. That can seem like forever when you are melting down a device that is already fed with more current than should be allowed.

The idea that it is "unlikely" that a ballast could short out and need circuit protection is erroneous - my crew and I made a damn good living for a lot of years fixing problematic electrical devices all day, every day. Electrical installations seem pretty benign in our experience because they have been built to very rigorous standards that resulted from fire insurance companies founding the NEC (National Electrical Code). The high volume of cheap offshore electrical gear available is raising the need for proper circuit protection, not reducing it.

*Rant off*

http://www.ebay.com/itm/Heavy-Duty-...564?pt=LH_DefaultDomain_0&hash=item27dedd6024

http://www.ebay.com/itm/HUBBELL-REC...947?pt=LH_DefaultDomain_0&hash=item27d2baa953

 

[theother]

Yes, if you are running a 30a breaker, all downstream components must be rated at 30a or greater to be code compliant.

30a/250v twist-locks would work, but they are usually more expensive and most of our applications don't require that level of strain resistance. 30a straight-blade plugs are both huge and expensive (think dryer plug/receptacle) - the size is indicative of the amount of power available there in an instant. It is usually cheaper and easier to get the protection in on the front end (breakers or fusing) than to build the system to withstand that level of power. Remember, there is a time-current curve for a breaker to react - a brand new breaker that meets all factory specifications can take several minutes to react to a substantial overload. That can seem like forever when you are melting down a device that is already fed with more current than should be allowed.

The idea that it is "unlikely" that a ballast could short out and need circuit protection is erroneous - my crew and I made a damn good living for a lot of years fixing problematic electrical devices all day, every day. Electrical installations seem pretty benign in our experience because they have been built to very rigorous standards that resulted from fire insurance companies founding the NEC (National Electrical Code). The high volume of cheap offshore electrical gear available is raising the need for proper circuit protection, not reducing it.

*Rant off*

http://www.ebay.com/itm/Heavy-Duty-...564?pt=LH_DefaultDomain_0&hash=item27dedd6024

http://www.ebay.com/itm/HUBBELL-REC...947?pt=LH_DefaultDomain_0&hash=item27d2baa953

So you are saying that it should be set up like a 30 amp breaker feeding a 20 amp sub panel with the 20 amp receptacles on that? Not doubting it, just making sure I understand clearly. Starts to make a light controller look like a good deal.