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Floating ground on a school panel made every motion sensor go nuts
Was doing a routine service call at a middle school in Dayton and opened up their intercom panel to check the master box. Someone had left the ground strap barely hanging on, just one thread of copper touching the lug. Volt meter showed 8 volts floating on the chassis, which explains why the motion sensors were false tripping every time the bell rang. Took me 10 minutes to re-crimp it and add a dab of corrosion inhibitor, but that stray voltage was making the whole system see ghosts. Anyone else run into floating grounds on commercial panels that mess with alarm zones?
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jesse846d ago
Had the same thing at a church job where the ground wire on the fire panel was loose and it was back feeding through the conduit. What fixed it for me was running a dedicated ground back to the main service instead of trusting the old pipe ground. Once that was solid the zone faults cleared up and stayed clear.
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