Learned the hard way why old screw terminals beat new plug connectors

I spent last Tuesday swapping out a controller in an old Otis elevator downtown. The original wiring used screw terminals that were a pain to work with but held solid for 20 years. The new plug connectors I installed looked great and saved me an hour of labor. But on my third callback this week, I found two of them had loosened up from normal vibration. The building manager was mad about the downtime and I looked bad in front of my crew. Now I go back and zip-tie every plug connector tight, or I just stick with screw terminals if the unit sees heavy use. Anyone else find plug connectors more trouble than they are worth on high-traffic elevators?

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oliver7194mo ago

@christopher713 nailed it with the zip tie trick, I do the same on every high-traffic unit now.

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christopher7134mo ago

Man, I feel your pain on this one... I had a similar mess over at a hospital job in Pittsburgh a few years back. Put new plug connectors on six elevators, and by the second month three of them had the same issue with vibration loosening them up. The nurses were not happy with me, and I had to eat the labor on the callbacks. I'm like you now, I'll wrap a zip tie around each plug connector on any high-use unit just for my own peace of mind, or I'll go back to screws if the customer can spare the extra labor time. Screw terminals might be slower but they just don't wander loose over time...

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