I always thought that properly installed ferrules were a good idea and badly installed ones were worse than none at all.

It does depend somewhat on whether or not the ferrule itself is incorrectly crimped, or whether the terminal to which it is connected is loose.
If its the former, its as per what 3DDave said. There is possibly an argument that using a screw terminal can mitigate the risk of an incorrectly crimped ferrule, although its not one I'd put much faith in.

Ferrules are effectively mandatory on flexible stranded wire when used with push-in or spring style terminals, less so on screw type terminals, although they're generally considered best practice to use, as it helps prevent loose strands from contacting things that they shouldn't.

I've had far more issues with poorly tightened or incorrectly inserted screw terminals than I've had with ferrules.

EDMS Australia

I never use ferrules and find them annoying and problematic. Most terminal blocks are designed to not use them, so yet another time consuming additional problem causer I just pass on. I find them faulty occasionally.

I prefer spring clamp type terminals as they don't loosen and aren't dependent on a guy with the wrong size screwdriver tightening them to a reasonable torque.

Keith Cress
kcress - http://www.flaminsystems.com

After a lot of googling it appears the pros of not using them is a non ferruled connection is generally more secure and flexible. A ferruled connection’s advantages are less issues with stray strands, oxidation and somehow also less noisy.

It’s google though, so I need to research more.

"I am stuck on Band-Aid brand, 'cause they are stuck on me"

Depends what you mean by 'ferrule' - personally I hate the bootlace-type ferrules. On the other hand I think the CEGB-pattern lipped blade lug is absolutely excellent when used with the correct RSF Series terminals - even if you leave the screw connection loose, a powerful spring retains the lug which latches into a groove in the busbar.

When I worked for a German mfr (K-M) decades ago, we were required to use ferrules on all connections. Here in the US, that practice was basically unheard of at the time and we got nothing but complaints about them. As I saw it, the saddle clamps used on most devices, such as relays and pilot devices, were designed to apply spring-like pressure to the terminals and keep the wire(s) under control. But with the ferrules, the saddle clamp was not able to "smash" down on them in the same way, leaving them vulnerable to vibration.

I did a huge control system project for a dam on the Columbia River in the late 70s. The Army Corps of Engineers wanted ring tongue terminals on everything, but you can't do that with IEC devices that are finger safe, so I had to convince the COE that the ferrules in the saddle clamps was just as good. They had me stand in front of them with a relay and a wire coming off of a terminal with a ferrule while they added weights to the other end of the wire until the ferrule pulled out (picture in your mind, the background scene in Monty Python and the Holy Grail where they are experimenting with sparrows holding coconuts...). I managed to convince them that it was just as good. But a year after installation, there were so many loose connections that we had to send wiremen out there for 4 weeks to remove every ferrule at our expense and replace them with locking fork tongues. Dams are continuously vibrating, I guess that was too much for the ferrule system.


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