Wiring Optex IR beam detector to ELK M1 Gold ~250ft run?

[stealth71]

I am working on hooking up an Elk M1 Gold and got a Optex AX-70TN to place across my driveway.  The location this will be located is approximately 250ft from the main panel.  I ordered some direct burial 18 gauge wire to run for the contact portion of the sensor and I think that should be adequate?  Is there a maximum distance to run zones on the M1?
 
The Optex AX-70TN takes 10.5 - 28V DC @ 38mA max.  My next question is how should I power this?  I have 120V AC available close by and could use a 24v or similar wall wart in an electrical box outside, but I was concerned about the longevity of a cheap wall wart.  Should I invest in a better DC power supply and then run wire 250ft to the sensor?  If so, any recommendations on power supply or wire size for this?
 
Thanks for the help.

 

[ano]

The length shouldn't be a problem. The problem is you have this device in your yard, that could be struck by lightning, and that wouldn't be too good for your ELK.  If you can isolate it somehow, that is always best. There are lots of people here that had lightning strike their sprinkler valves and that destroyed their panels, if not worse. You need to protect against that.
 
I myself do what you are doing, but instead of wires going back to the panel, I use wireless sensors. The main reason is lightning.

 

[stealth71]

That is a great point.  I will look into using an optocoupler on the circuit somehow.  Anyone have any experience with them?
 
Back to do more research.  Thanks for the input.
 
Any recommendations on powering it?

 

[Del91574]

Optically isolated, nothing is going to get by that unless the lightning bridges it completely, then nothing is going to solve that unless you clamp it to ground (westom) before the transient voltage gets to a damaging level.
 
How it's powered depends on whether or not it's going to be used for annunciation or security and if running without AC is desired. ACT international used to offer a 4 zone unit (4201). Not sure if they're still out there.
 
The big thing would be to make sure the power source is regulated and filtered.