question on wiring a 240v system

[rives]

There are lots of ways to accomplish it, but if you have a heavy feed coming into your controller (above 20 amps), then there needs to be some intermediate protection set if it ultimately winds up powering 15 or 20a receptacles. This can be done with some internal fusing, track-mount circuit breakers, a small sub-panel, etc.

Most of the commercially-built light controllers that I've seen fail to this. It's relatively expensive (at least compared to not providing protection) and it is a highly competitive market. They won't meet code and they will invalidate your fire insurance on the off chance that it would cover a loss in a house with a grow. These companies will frequently tell you that their controllers are code-compliant - they just don't tell you where. They rely on a very tightly delineated portion of the code that only applies if every one of the restrictions are met. The code provision is designed for warehouse lighting, with a cord connecting the ballast to the receptacle that is less than 2' long, the cordset is listed (tested and published as being appropriate) for that service, the ballast hangs immediately below the receptacle, the cord is visible over it's entire length, etc. In short - it will never apply to any of our installations and will be illegal for use in them.

 

[Redbuddz]

if you're going to be controlling both 120 and 240 volt lighting you would then want to use a 3 conductor cable with ground. that's 4 conductors in total. A black, red, white and a green/bare. If you're only using a 2conductor feed for 240volt lighting, then you have no neutral/white for any 120v lighting you may use in the future.

BreezE. I believe you said you may have a total of 9 x 1000watt lamps @ 240v that draw 5 amps ea. 9 x 5 = 45 amps, that's much more then 30amp wire can handle and it's more then a 40 amp wire can handle. You would likely have to use two 30amp circuits to power your lighting. You could likely still use one timer as they do make them to control two circuits but you would have to use two sub panels, one for each 30amp circuit.

I use whats known as a Contactor. A contactor is just like a relay where a control device makes or breaks a connection. The control device for our purposes is a timer. When using a contactor there is no real load for the control, it just controls the on/off of the contactor. By using a contactor I can use any cheap timer to control it and because there is no real load for the control circuit I can use as many contactors as I want and they can all be on just one timer. They sell contactors that can be controlled by a 24volt, 120 volt or 240volt circuit and they sell them to control single pole, two pole, three pole and even 4 pole. 4 pole is great cause you can control two 240volt circuits. Contactors cost about 30-200 for any that we would be using. When buying a contactor Full load amps is what you're interested in and I would always go one size larger. i.e. if you're controlling 20 amp circuits then I would buy a 30 amp contactor. the installation of a contactor is very simple. typically you would mount the contactor in a large J box or a pull box. I use a pvc pull box usually about 8x8 or 10x10 so that I have enough room to work.

 

[rives]

All of the above is very good information.

I would add a couple of things - I prefer to use smaller power relays and split the circuits up rather than a single large contactor. This minimizes the large spike in consumption when the lights switch, and it allows you more flexibility in your control scheme, such as dropping selected lights offline if the temperatures get too high.

All amps are not born equal. If you look at a quality contactor/power relay, it will show an amperage rating for several types of loads- resistive, inductive, HP, capacitive, ballast, etc. Many cheaper components will only list the resistive rating, which is the easiest type of load for the contacts to handle. Unfortunately, resistive ratings are virtually worthless to us. For instance, a Honeywell water heater timer is rated at 30 amps resistive load, but only 10 amps of ballast loading.

My preference for an enclosure is metal. The plastic variants are more economical and sometimes more easily sourced, but they cannot be grounded. Grounding is necessary to make the circuit protection work properly, and it also helps to shield the electromagnetic interference that the components create.

 

[Redbuddz]

Rives you sure do know your electrical. Yes, there are several types of contactors to choose from so you do need to be aware of which one you are using. Most times they will be called a lighting contactor so that makes it easy to get the right one.

Metal enclosures are fine but I prefer the pvc enclosures because they hold up well in the humid grow environment and they are easy to work with as well.

I hope we are not confusing BreezE too much?

 

[rives]

Thank you. It's a more positive side effect of 30+ years of industrial work than the banged up body and gray hair.

Breeze was getting a bit overwhelmed, I think, so he jumped over to PM. I thought that there was some good information being passed along here for other people and decided to keep contributing to the thread.

Appreciate your input Red, welcome to ICMag.

 

[theother]

Thank you. It's a more positive side effect of 30+ years of industrial work than the banged up body and gray hair.

Breeze was getting a bit overwhelmed, I think, so he jumped over to PM. I thought that there was some good information being passed along here for other people and decided to keep contributing to the thread.

Appreciate your input Red, welcome to ICMag.

agreed, this thread brought up some interesting stuff. Gotta say, its amazing to me that I have never seen this brought up before and as far as I know, no one really does it. Would be cool to see someone make a proper tutorial or diagram on how to accomplish this. I agree with you above though, if its not cost effective I doubt it will be adoptedby the majority.

 

[Redbuddz]

Thanks for the warm welcome Rives. I have been seeking answers here in the forums so I do my best to chime in when I can do so knowledgably. Breeze does seem to be confused. I hope he gets its figured out correctly.

 

[rives]

agreed, this thread brought up some interesting stuff. Gotta say, its amazing to me that I have never seen this brought up before and as far as I know, no one really does it. Would be cool to see someone make a proper tutorial or diagram on how to accomplish this. I agree with you above though, if its not cost effective I doubt it will be adoptedby the majority.

It depends on how you define "cost effective". With what has been a largely illegal market, the manufacturers have had an open season on what they have been sourcing. Who are you going to complain to? The other problem is "the sweetness of cheapness" - since they are operating outside of a regulatory environment, the competition to have a lower-priced product takes precedence over having a safe product, and further detracts from product safety. Additionally, people have become very complacent about the risks because, properly implemented, electrical gear is very safe. It is almost unheard of for people to get hurt or killed from equipment that truly meets code and has been tested by UL or the equivalent. I think that most people assume that everything on the market meets those standards, and that simply isn't the case.