Appreciation post: the 30 second rule for checking cannon plugs

I was working a Collins HF radio swap on a Gulfstream GIV last week and overheard a senior tech mention he always waits 30 seconds after unplugging a cannon plug before touching pins. He said it lets any static charge or residual voltage bleed off from the backshell. Never really thought about it before but now I do it every time. Anyone got other little habits like that they swear by?

2 comments

2 Comments

david82121h ago

Started doing the same thing after I found out the hard way @price.alice, got a decent jolt from an old pitot heat connector that still had a charge after sitting unplugged for maybe 10 seconds. The 30 second wait feels like overkill sometimes but it's cheap insurance when you're dealing with high impedance circuits that hold a charge longer than you'd expect. Works best on the big multi-pin plugs from my experience, the smaller ones seem to bleed off way faster on their own.

price.alice1d ago

Oh hey, that's a solid tip right there. I never thought about it that way but it makes total sense. The way I see it, those cannon plugs can hold a charge just from the dielectric in the backshell alone, especially in a dry hangar with low humidity. Do you find it matters more on certain types of plugs or just all of them? I've seen guys get zapped by old nav light connectors and that's not just a static pop, that hurts.