Ferrule Current Rating

[400Hz]

Hello,

Enjoy reading the posts on this forum so decided to join in!

Do we need to be concerned about current rating when selecting a ferrule?

I have been researching a future CU change + Re-wire in my own house. When looking for suitable ferrules to install on some of the CU terminations, I came accross the RS PRO range. They do a 2.5mm ferrule however it only has a current rating of 9A. I thought this was a bit odd as a 2.5mm cable can potentially carry more than 9A.

https://docs.rs-online.com/bf70/A700000007531077.pdf
ON looking at other brands, very few even mention the current rating of the ferrule. I would have thought you would need to install a ferrule with a current rating of at least the expected circuit current?

Anyone seen a discussion about this before?

 

[400Hz]

Any thoughts anyone?

 

[roys]

Might be a better question to send to RS tech dept, I suspect a typo.
When you consider that the copper from your cable goes inside the “tube” so it will still be the cable carrying the current, I don’t see anything to worry about, although I have been known to be wrong once or twice in the past.

 

[UNG]

I have used loads of them and never really considered the current rating and never known any to fail, as mentioned in the previous post you have the cable enclosed in a tube which has got to offer a better connection that just inserting a multi strand cable into the terminal connection
As an alternative if you were to tin the end of a multi strand cable to stop the strands splaying would you question the current carrying capacity of that method

 

[Geoff1946]

As an alternative if you were to tin the end of a multi strand cable to stop the strands splaying would you question the current carrying capacity of that method

As an aside, I hope you are aware that you should never tin cable ends. The soft solder when clamped under pressure will compress, leading to loosening of the connection and eventual failure.

 

[SPECIAL LOCATION]

Hello,

Enjoy reading the posts on this forum so decided to join in!

Do we need to be concerned about current rating when selecting a ferrule?

I have been researching a future CU change + Re-wire in my own house. When looking for suitable ferrules to install on some of the CU terminations, I came accross the RS PRO range. They do a 2.5mm ferrule however it only has a current rating of 9A. I thought this was a bit odd as a 2.5mm cable can potentially carry more than 9A.

https://docs.rs-online.com/bf70/A700000007531077.pdf
ON looking at other brands, very few even mention the current rating of the ferrule. I would have thought you would need to install a ferrule with a current rating of at least the expected circuit current?

Anyone seen a discussion about this before?

I think you will find that the ferrule manufacture would have to ensure the materials they select are compatible with the current rating of the conductors sizes that they will be crimping.... Which is why current rating is rarely mentioned..

e.g. This data sheet only mentions 600v under its "Ratings heading"
https://www.expresselectrical.co.uk/files//157e2abf-3933-4948-9a91-ad1700bc9ecc/expressTERM Cord End Terminals.pdf

Although this webpage does mention that "Current carrying capacity dependent on cross-section"
https://www.elfa.se/en/bootlace-ferrules-insulated-rnd/pf/1578081

And..
don't forget the current rating is primarily relative to any potential problems due to overheating of a conductor , (melting insulation etc.),
and as you have a stranded conductor, inside a metal sleeve, clamped inside a cable termination...
Providing the terminations is secure.. (correctly torqued), Both the cable and cable terminal will be sufficient to carry the expected current..

In my opinion it is very unlikely that any ferrule would need to dissipate any heat that either the cable or the terminal block hasn't already dealt with!

The DIN 46228 spec if you want to purchase a copy to read would probably tell you more..
But I think they are good for typically 105degrees C

 

[400Hz]

Thanks very much for the responses which all seem very sensible. I will contact RS out of curiosity to try and find out why they include the rating they have.

 

[bglproserve]

As an aside, I hope you are aware that you should never tin cable ends. The soft solder when clamped under pressure will compress, leading to loosening of the connection and eventual failure.

I agree, however, ferrules are tinned copper contacts, Just Saying.

 

[Andy™]

I agree, however, ferrules are tinned copper contacts, Just Saying.

ferrule may be tinned copper, however it is a very different connection from a tinned/soldered wire end. Just Saying.

 

[Geoff1946]

I agree, however, ferrules are tinned copper contacts, Just Saying.

Ok. To be pedantic, never tin cable ends with soft solder..........

 

[awarner]

The issue could be surface contact, after crimping the only the top and bottom of the ferrule is making contact with the terminal which with give a higher resistance connection, one reason I use a flat type crimp pliers and not square. From a thermography aspect a lot of high temperatures I find are poor terminal crimps than the actual screw of the component it connecting to.

 

[Stevie G]

Hi I worked for a controls manufacturing company for over 25 year, which included building control panels, to carrying out installation on site ,and then final commissioning the complete job .
i have used fork crimps ,bootlace ferrules, ring crimps the full gambit without issue ,but the crimping tools issued were Weidmuller crimping tools . Although expensive ,will out last cheaper alternatives . www.weidmuller.co.uk/en/index.jsp
The only issues we had ,was due to a slack connection caused by panel wireman not tightening the screw or bolt properly.
The control panels we built were for North sea oil rigs, Mossmorran in fife , HVAC control panels etc