Warning / Disclaimer: This procedure should only ever be carried out by a professional a licensed electrician in accordance with AS3000 and The Electricity Act

A common problem indoor growers face is timers failing .

The reason they fail is due to the highly Inductive current load  (from HID and fluorescent lighting as well as fan motors) literally burning and ruining the metal contacts as they are opened and closed.
The cheap timers claim they can switch 10 amps, but this can be misleading. The maximum current for the type of load we want to switch(highly Inductive) is usually much lower again, sometimes as low as 2 amps, which does not even give us enough for a 400w on start -up.
A way around this problem is to use the timer to power the coil of a contactor. Below is an image of the one we will be using in this tutorial, it is called a Hagar 25amp, single phase contactor.

The contactor above has purpose built contacts and aparatus, suited to switching highly Inductive loads, up to 25amps on this model, that is readily available off the shelf at most electrical wholesalers that stock the Hagar brand.
Ok, to get started we will need

Materials

• 2 x 3mtr 10amp extension leads $7
• 1 x 6 outlet power board $5
• 1 x Timer $7
• 1 x Hagar 25amp single phase contactor $45
• 2 X screw connectors $1
• 1 x roll Insulation tape $2

Tools

• Blade and Philips screw drivers
• Knife
• Pliers
  

Here is an image of the materials and items we will be using

Cut the female socket off 1 extension lead.

Using the knife and pliers trim back and prepare the brown and blue wires. Tape the green/yellow wire off

Connect the brown wire to terminal A1, blue wire to terminal A2. This is the timer lead.

 Cut the female socket off the other extension lead and cut the 3 pin plug off the power board

Trim back and prep the cables

 Connect the brown wire from the extension lead to terminal 1, and the brown wire from the power board to terminal 2

Twist and double over the copper on the brown and green/yellow wires

Secure your connectors

Contactor should be housed in a suitable enclosure to keep fingers away from live terminals,  and then thats it folks

Warning / Disclaimer: This procedure should only ever be carried out by a professional a licensed electrician in accordance with AS3000 and The Electricity Act 

by Bufo Marinus
editor: Pure