Help with fitting end-ferrules in Shelly relay screw terminals? - Page 1
Forum section: electronics / projects

author: victorhooi
author_rank: Regular Contributor
timestamp: November 27, 2024, 12:34:05 pm
content: I'm trying to install some Shelly relays (e.g. Shelly 1PM Gen 3 Mini), and I'm some trouble getting the end-ferrules into the screw terminals.I'm using theKnipex Twistor16crimper, which should be a square profile. (I just noticed that Knipex also has aKnipex Twistor Tcrimper as well - which has a trapezoid profile)The wire is 2.5mm^2 (14 AWG), and I'm using the blue DIN26228 sleeves (which I think should be the 2.5mm^2 ones).The bare stranded wire fits into the terminals fine - but once you put the end-ferrule on, I can't seem to push it in.(There was a similar question on the Shelly FB support grouphere, but nobody there seemed to have any solutions).Does anybody have any ideas on how to fix this? Would a different crimping tool, or type of end-ferrule work better?

author: jwet
author_rank: Frequent Contributor
timestamp: November 27, 2024, 03:42:24 pm
content: I use ferrules like this for CNC wiring often to DIN Rail stuff/PLC logic. Makes for the a nice install. Those Knipex crimps are cool- may have to get some.I prefer the compression type crimpers- I use a square crimper now but had a hex at one time- I think Weidmuller makes these- even more expensive than the Knipex- might be slightly smaller. A lot of installers just use standard crimpers- the ferrules go a bit flat, this may be better in your case- doesn't look as clean. Do a pull test to make sure that they're really on. Does Shelly have any guidance? Do they have a aperture size and recommendation for ferrules. Take to their apps department.Also, you don't have to use ferrules- its nice but its not required. You can tin ends to keep them from birdcaging or use nothing. If you do a lot of tinning, get a small solder pot, dip in low residue flux and then into pot. Ferrules are nice for maintenance as the wire doesn't get so beat up after multiple matings but tinning and even nothing works ok especially for something that's going to stay togethere.Good luck.

author: Ian.M
author_rank: Super Contributor
timestamp: November 27, 2024, 04:27:47 pm
content: Only tin the very end of stranded wire, not the part that will be in the clamp, as solder cold-flows under the clamping pressure, resulting in a loose connection, with a risk of overheating and possibly fire.

author: ajb
author_rank: Super Contributor
timestamp: November 27, 2024, 05:05:08 pm
content: Quote from: victorhooi on November 27, 2024, 12:34:05 pmIs the wire 2.5mm2or actually 14AWG, which is 2.08mm2? In most cases the DIN sized ferrules work fine for AWG wire, but there are ferrules specifically sized for AWG that will work better if that's what you have. Or it might be possible to squeeze the wire into the next DIN size down.That may or may not make a difference here, though -- for any given terminal, there's always some size of wire that will fit without a ferrule but not with, so unless you can downsize the wire, going without is your only real option.

author: Buriedcode
author_rank: Super Contributor
timestamp: November 27, 2024, 05:07:35 pm
content: I ended up buying the hex crimpers (a cheap clone of the kipex, but it works well) for this reason - some screw terminals prefer square profile, some a rounded profile, so the hex crimpers works better for the latter.

author: floobydust
author_rank: Super Contributor
timestamp: November 27, 2024, 07:07:58 pm
content: The terminal blocks are too small for 14ga+ferrule. The whole module is made to be small.They are also low quality chinese specials so the tangs can get bent down and in the way. If I need to stuff something in there, I'll raise up the screw and then poke a screwdriver inside to push the tang up. Try that or there may be simply not enough room.