Automating a 220V Pool Pump using a standard Home Automation Light Switch and a Contactor

I had some spare Insteon Switchlinc Relays remote control switches and wanted to control my pool pump remotely, and put it on a programmed run cycle based on the hours of daylight, sunrise and sunset. There are 220V controls that can be purchased for loads such as pool pumps, but they tend to be expensive. My solution was to use a standard remote control light switch 110V with a small contactor (industrial relay) to control the pool pump. In order to do so, you have to purchase a contactor with a 110V coil (that can be controlled using the light switch) and contacts rated for the load you need to switch (voltage and current).
Electrical boxes arranged for incorporation of the contactor
For the installation of the contactor I used a small 4 x 4" plastic junction box. In the photo above, note the small length of DIN automation rail that I installed in the bottom of the junction box. My small Siemens contactor had a DIN rail mounting interface, so that made the installation of the contactor in the plastic box very simply. I oriented in the cables entering the junction box so that the routing around the contactor would be direct and simple.
Devices installed - switches and contactor
 I used a double switch box to install my Insteon Switchlinc relay switches. The left switch controls a ceiling fan used to keep excess heat from building up in my pool shack. The right switch controls the coil of the contactor, switching it on or off. The bottom box is a manual disconnect switch which was originally used to control the pool pump motor. I decided to keep it - to give me a safety lockout switch to allow me to cut power to the pool pump, and avoid the possibility that automation turns on the pool pump while I'm working on the pump, cleaning a filter, etc.
Detail of the contactor installation
Here's the detail of the contactor installation. This small Siemens contactor cost about $20 on eBay, and has been running perfectly for about two years now. 

I've written a program in my ISY-99i which runs the pool pump for 8 to 12 hours a day, depending on the length of daylight on a daily basis (sunrise and sunset). In addition, I've added a program that switches the pool shack ventilation fan on anytime the pool pump is running, to ventilate excess heat from the shack. All works perfectly. This contactor also switches the line power for my Salt chlorination system - I'll write a separate post about that in the near future. 

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