Building and buying an HPS system

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Building and buying an HPS system

Contributed by: furun
Submitted: 09-07-2003


Lighting is a very important component of your grow. You could have the best genetics, the perfect growing space, and tons of knowledge, but without adequate lighting, your grow will simply not perform. This article is not in any way designed to dissuade a person from using fluorescents or MH. This faq is a guide for those that would like to know more about HPS lighting systems and how to buy, assemble, and use them.

Pre-assembled HPS lighting systems can be expensive. Most of the cost is overhead and labor. If you were to buy the components separately and put it together yourself, you can save hundreds of dollars with only a small amount of quality sacrifice. Also, when you build it yourself, you have a wider range of products to choose from, so you can build a system that is right for your situation.


The first step in building a system is to know exactly how much light you need for your area. This FAQ will give you an idea of what you will need to buy: ********

Parts required:

ballast w/ igniter and capacitor
extension cord w/ ground wire

ballast case

wire cutters and strippers
wire nuts
electrical tape

Obtaining parts

To begin on your quest you will need to shop around places in order to find the best deals. You can order the parts you need from the Internet, or you can buy them at a local electrical store. We will discuss Internet purchasing later on.

Many of you that live in larger cities will be able to call around to many electrical stores that will carry HPS ballasts and do some comparison shopping. Those in smaller cities might not have a great selection. If you look in the phone book under electrical suppliers, you will see wholesale and retail suppliers. You can get prices from both, but when you call the wholesale store, you will have to ask them if you can buy without an account. Going with the wholesale store will most likely be the cheapest, as they will have many types of ballast in stock. It is important that you ask them if you can buy them individually.

Also, you will need to know exactly what you want. You can buy 70 and 150w HPS at Lowes or Home Depot, so I am going to concentrate more on 200w and up. The available wattages are 200, 250, 400, 430, 600, and 1000. You will need to determine what voltage you are going to be using (household current in the US is 120v). It is very important that you buy a ballast kit that is compatible with the voltage in your house. Most places will sale multi-tap ballasts which have higher voltages along with the standard 120v. This will probably be your best bet.

If you wish to order online, there are plenty of stores that you can choose from. You might also want to do searches on google to find other deals.


From store:
Pay in cash, nothing with your name on it (no paper trail)
Act calm and confident. If you act shady, they might report your license to the authorities.

Know what you are going to buy before you get there, so you can just walk up and ask for it.

Make sure that company sends the packaging in discrete packaging. Nothing with Hydro, Horticultural, or any other growing references. This will help ensure that your package will not be watched. This is also good if you are getting it shipped where people will not know of your operation.
Always make sure you check out the return policy on damaged and non-operational equipment.

For my example, we will put together a 400w HPS lighting system: (example prices)

ballast (400w includes igniter and capacitor) $69.29
porcelain mogul socket $13.20
bulb (There are many different bulbs, each with different spectrums. This is a cheap bulb) $16.15
20' extension cord (length will vary) $8.00
wire nuts and electrical tape (estimate) $4.00)
TOTAL: $110.44

Accessories. Reflectors are not necessary, but even a cheap batwing style reflector will benefit you by directing the light where you want it. Ballast boxes are also not necessary, but having one reduces the risk of electric shock, burning, and fire.

Optional parts
reflector(batwing) $30.37
batwing reflector $21.67
TOTAL: $52.04

Grand total: $162.48 + shipping

The items listed above will give you a fully functional HPS system that is much like one that you can buy.

If that price is too high, the reflector and ballast box are expendable. You can make your own reflector and you can mount the ballast on just about anything that can take screws. Doing so, introduces the risk of you touching the ballast components and getting burned or shocked. As long as caution is exercised, you have nothing to worry about.

Additional Options

Air-cooling is another option that people would like to look into more often. Having separate ventilation for your lights will ultimately benefit you as you will have more head room for your plants to grow and the temperature will be greatly reduced.

There are 2 method of obtaining an air-cooled reflector/hood:

1) You can build your own using:
This FAQ on how to build an air-cooled hood, with integrated carbon scrubber, and light trap (for the true DIYer)
This FAQ on how to build a cool tube *recently updated
Note: If you are going to make the cool tube from above, you can hang the cool tube assembly underneath a stationary reflector, which can either be homemade or manufactured.

2) You can buy a complete air cooled hood online, or at hydro stores


Now that we have all the parts that we need, we need to wire up the ballast and assemble the light together. I will point you to this FAQ that taught me how to wire my first ballast.

Connector plugs

A good way to connect the socket to the ballast is to install a set of connector plugs between the ballast and the socket. This will enable you to disconnect and move the light without having to disturb your wiring. Also, you can locate the ballast in another area as to keep heat down in you grow area.

Take a 10' - 15 extension cord and cut it into 2 lengths. The shorter one should be the male end (the one with the prongs) and the longer one should be the female (the one with the holes). You will probably want to have the shorter one be around one foot long. It is the piece that is going to be connected to the socket/bulb assembly. The longer piece will need to be long enough that it can reach the other piece of cord from wherever you are going to place the ballast.

Note: We attach the ballast to the female side in order to reduce danger of electric shock. In a rush to pull apart the set up, a person might leave the ballast on and accidentally touch the prongs on the wire. Trust me; you don't want to get shocked by a ballast of any wattage.

Connect the white wire from the male end of the extension cord to the white wire of the socket. Connect the black wire of the extension cord to the black wire of the socket. Connect the green wire, if you bought a socket that has a grounding terminal.

You will want to connect the female plug to the ballast. Connect the white or COM wire that is coming out of the igniter to the white wire of the extension cord. Connect the black wire from the extension cord to the RED or X2 wire coming from the igniter. You can also connect the green (ground) wire to the same place that you grounded your ballast.

Additional Information


Remember not to spray water on or near an exposed HPS light bulb, especially when its on (foliar feeding may cause the bulb to explode if water touches the bulb)!
Do not look directly into the HPS for any amount of time. If you are going to be in your grow room for a long amount of time, wear sunglasses
Do not touch an HPS bulb while it is hot Do not touch an HPS ballast while it is hot
Replace your lights every 10000 to 15000 hours
  Last modified: 00:15 - Aug 29, 2003  

faq:1563 "Building and buying an HPS system"