Question about always using a new wire run for every sensor

Last week I was finishing a job in a two story house in Tacoma. The owner wanted a sensor on every window, about 28 total. Everyone says you should run a fresh wire for each one to avoid trouble. But three years ago on a big commercial job, my boss had me daisy chain a whole floor of door contacts on one loop. We used a 22 gauge, 4 conductor and it worked perfect for 5 years until I drove by and saw the place was still using it. Last month I did it again in a garage workshop, linking 4 motion sensors on one run to save maybe 2 hours of fishing wire through finished walls. It passed inspection fine. I think if you calculate the resistance and keep the run under 200 feet, chaining is totally fine for basic zones. Has anyone else had good results with this on residential jobs, or am I just getting lucky?

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3 Comments

maxl935mo ago

Honestly, I always ran separate wires, but your real world example makes sense.

7

miller.diana5mo ago

Switched to a shared ground last year and haven't had a single issue since.

0

lucast815mo ago

I mean, maybe it's just me but I've seen daisy chains fail after a few years when one sensor goes bad. @maxl93, I get wanting to save time, but troubleshooting a whole loop is a nightmare later on. I'd rather spend the extra hours now than get called back.

2