Pioneering Hydroponics

Since 1976

Green Power Pro Grow Light Timer & Contactor

Safely control the day and night settings of 2 to 8 HID hydroponic grow lights with UK built Green Power Professional range of timers & contactors.

Up to 8 lights can be controlled from 1 Green Power Pro Lighting Contactor.

These robust contactors control the ‘on’ and ‘off’ periods of lights and fans without wires trailing and without risk of your timer burning-out.

Contactors are essential for growers wanting to automate grow light on and off periods because standard timers can’t handle the electrical surge of HPS and HID lights used for plants.

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GreenPower Contactors safely and reliably switch lighting ballasts and fans on and off according to the schedule that you set on the contactor’s timer.

Each of the contactor’s sockets is individually switchable, so you don’t need to run all the grow lights all the time.

Every aspect of GreenPower Contactors is designed with safety and reliability in mind…

  • Made from steel
  • Galvanised wall-mountable back plate the width of the entire unit
  • Thick rubberised cable – no risk of light degradation
  • Built-in Grasslin timers
  • UK designed and built
  • 2 year warranty

These are heavy duty contactors which send power to the ballasts bank-by-bank to avoid big surges and they feature…

  • Circuit breakers
  • Time delays to protect ballasts in the event of short power failures
  • Battery reserve on the timer.

Note: Commercial units must be hardwired by a qualified electrician.

Why use a Contactor?

Plants need a period of darkness, so most growers set a timer to turn their grow lights on and off at specific times. The HPS and HiD grow lamps generate a large spike in electricity when switching on.

Without a contactor this electrical spike travels through the timer and is enough to cause the timer to burn-out, leaving the grow lights in the on or off position until you manually switch them.

With a contactor the power goes through the robust switching components of the contactor. The surge doesn’t go through the timer itself, so there’s no risk of burn-out.

How It Works

  1. Plug your ballasts and fans into the Green Power Contactor.
  2. Load the GreenPower contactor evenly, so if you are using 4 ballasts in a GreenPower 6 unit plug 2 ballasts into each side.
  3. Plug the contactor into the wall sockets.
  4. Set the timer on the contactor with the desired lights ‘on’ period. If you are plugging a fan into the contactor the fan will also switch on at the same time as the lights.

More Information

 Product Option


Max. number of ballasts

Maximum Load

250w, 400w, 600w


Pro 2




Pro 4




Pro 6




Pro 8




*maximum of 7 using 600w ballasts

Questions & Answers

Can I use a grow light contactor with an extension lead?

We advise you do NOT run a contactor from an extension lead. Likewise we advise you do NOT run an extension from a contactor socket. Both these actions are unsafe as they are likely to lead to overloading.

Why do some of your contactors have 2 plugs?

The contactors have 2 plugs because UK mains plugs have a maximum safe draw of 13 amps. A 1000W ballast can require around 5 amps, therefore to safely draw enough power for more than 2 x 1000watt lights (10 amps) you need to use more than one wall socket.

I have a spare socket in my contactor, what can I use it for?

If your grow room is too warm you could plug a fan into the spare socket. The fan will run when the lights are on and keep the temperature down and the air flowing.

Can I run a combination of ballast sizes from one contactor?

Yes, as long as you do not exceed the maximum load. Add up the total wattage of the ballasts you plan to use and check the guide above. Due to the variances in different ballasts you should also ensure that the total current requirement on one side does not exceed 13 amps.