DIY 400 watt Metal Halide

Amazon.com: INTERMATIC TIMER 2HP-240V-5000W: Electronics

 

Thanks for the link, is there a way though to connect to a controller like an aqua controller if its wired for 240v?

 

Yep sure is. I use one of these

 

Sorry to reply so late.
I used relays. They were double throw double pole (dpdt). On my ballast I had two common wires and one 240v wire. One of the common wires is used as the second leg for 240v. I put the common wire and the 240v wire on the two poles on the dpdt relay. The two 240v wires from the house are connected to the other two poles on the relay. The four poles are simple switches that are normally open and closed when the relay is energized. Each ballast wire is on a separate pole and the power wires are on the opposite side poles. I used a relay that energizes with 110vac. I also used a cheap extension cord to attach to the coil on the relay. I cut the receptacle end off of the cord and striped the wires then connected them to the poles for the coil. This cord can be plugged into a standard 110v outlet for always on or plugged into a simple 110v timer, mine came from Wall-Mart.
I hope this is clear enough. Feel free to ask more questions if it is not.

I used these relays. https://www.alliedelec.com/search/productdetail.aspx?SKU=8500290

and these sockets. https://www.alliedelec.com/search/productdetail.aspx?SKU=850-1075

This is a pic of my relay setup. If you look at the socket you will see that is has stepped sockets for the incoming and outgoing wires. The top of the sockets are 110v coil wires on the top step and the bottom are 240v wires from the house distribution panel. The lower wires are for the switched 240v wires. I used 4pdt relays so I have two ballast wire to one relay and on the other I have 1 ballast and a 240v fan. The fan is used to move air in the ballast box.
The relay on the farthest left is for 110v VHO ballast.