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TIL from a building engineer that changed how I wire cars

Had a chat with a building engineer last Tuesday about their old Otis units. He said most door lock problems come from ground loops not bad contacts. Hit me hard because I spent 6 hours chasing a ghost fault last month at a 12-story office in Phoenix. He showed me how voltage drops between floors mess with safety circuits. Now I check ground continuity before touching any door lock wiring. Anyone else run into ground loop issues on multi-floor elevators?
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2 Comments
sean_perry
Ground loops not bad contacts" he says like that's supposed to make me feel better about the 6 hours I'll never get back. I bet that engineer has never been elbow deep in a Phoenix elevator shaft in July.
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mitchell.mark
Honestly, what part of that took the longest to figure out?
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