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One Tuesday in March that tested everything I know about panel wiring
I had a rough one last month at a mill building in Lowell. The blueprints showed a clean drop ceiling path, but whoever ran the old wire had pushed it through an abandoned conduit filled with oil and debris. By the time I pulled the new runs through, two zones were showing half resistance and one keypad kept rebooting every 40 seconds. I spent six hours chasing a ghost until I noticed the transformer was strapped right next to a motor starter, and the harmonics were messing with the backup power. I finally isolated the panel on a dedicated circuit and added a filter, and it cleared right up. My partner joked that we should bill the building owner double for the education. Has anyone else run into dirty power issues that show up as false alarms on a fresh install, and do you test for that before pulling cable or only after trouble starts?
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the_ray13d ago
Before you even pull cable, put a scope on the panel and watch it for a few minutes during a shift change when motors kick on and off. Dirty power almost never shows up on a quiet afternoon, it hides until the building is running at full load. A twenty dollar plug in meter saved me a callback more than once.
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