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I finally saw someone use a 16/2 wire for a PIR sensor on a 200-foot run again.
It was on a job in Eugene last month, and the voltage drop caused the sensor to false alarm constantly. I learned the hard way years ago that anything over 100 feet needs at least 18/4 to keep the power stable for the sensor's internal components. Has anyone else found a good rule of thumb for wire gauge versus distance on these older sensors?
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the_tara6mo ago
Ugh, I just run 18/4 for anything over 50 feet now.
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grant8266mo ago
Running 18/4 cable for anything over 50 feet is a solid move for voltage drop. You're on the right track. For a 20-amp circuit at that distance, 12-gauge wire can lose enough voltage to cause problems with some tools. I'd only use 12/2 if the run was under 50 feet and the load was light, like just a few outlets.
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