What type of wire(gauge # of strands)would I use for motion detectors in offices?
Thanks
satellitescott

Solid thermostat wire would be fine. That's usually 18 Ga.

Many Alarm Companies use 22 gauge. Larger gauge never hurts, unles you have Many zones and space is limited, helps for long runs as well. Can be solid or stranded.
Most Motions need 12 Volts for power(red and black), the white and green are the loop. They are usually wired to the Common and NC(Normally closed)terminals. If you use 6 conductors, you can hook to 2 terminals marked "tamper", this extra pair can be hooked in series with your other detectors and will connect to a 24 hour tamper zone, so that even when system is disarmed, someone can't open and screw with it. Many don't tamper.
At least Tamper the siren can, they usually have at least 2(if opened, or if yanked from the wall) the alarm will sound, you can add vibration or other sensors if you like.
You don't have to use that color code if you want to make it a little more difficult for a pro.
Here is a good Company and site if you are not an Alarm Contractor:
Wm. B. Allen Supply - Wholesale Distributor of Alarm, CCTV, Fire, Sound & Access Systems Good Luck