Under Crimping - HV/MV Terminations

[dualrobin]

A question has been raised that so far we have not been able to find an answer for. In general it appertains to jointing solid Al conductor together using a Al through ferrule. If the CSA of the solid conductor is 185mmsq, with a diameter of 15.1mm, should we use an Al ferrule that is for 185mmsq cable with an internal diameter of 17mm or use an Al ferrule that is for 150mmsq cable with an internal diameter of 15.5mm. So long as we use the correct rated die for the appropriate ferrule will there be any problems? Somebody has stated that if we use the Al ferrule that is for 150mmsq cable with an internal diameter of 15.5mm on the 185mmsq solid cable then the resulting crimp will be 'under crimped'. What is under crimping? and can we do the above, advice would be appreciated.

 

[ScottyUK]

Are you talking about a single solid conductor or a solid-stranded conductor? Crimping single solid is generally a bad idea, although at that size I'm surprised if you have a single solid type.


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If we learn from our mistakes I'm getting a great education!

 

[dualrobin]

Scotty,
This cable type (36kv/185mmsq/Al/XLPE/Cu/50mmsq/MDPE) is a common cable on the railway infrastructure and is supplied and installed daily. The cable conductor is indeed a single solid aluminium strand with a diameter of 15.1mm (nominal). The exact specification is available at

http://www.eland.co.uk/railwaycable/powercable/cable85/mv-power-cable.html

 

[ScottyUK]

Thanks for the link - I haven't seen that conductor configuration before: the photo is more like what I'm used to dealing with. Sorry I can't help.


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If we learn from our mistakes I'm getting a great education!

 

[7anoter4]

I don't know what type of Al ferrule you intend to use. In my opinion the 150 sqr.mm stranded is good for 185 sqr.mm solid. The ferrule inner diameter has to be 15.8 mm and it fits on 15.1 mm diameter aluminum conductor. See :

http://www.elpress.se/elpress/fckImages/File/gb/Al-terminals.pdf

 

[waross]

Two questions;
Is the connector listed for solid cable?
Does the smaller connector have enough current carrying capacity?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[dualrobin]

The answer to both questions is yes.
The connector is rated for solid cable
The connector has enough current carrying capacity.

Thanks

 

[rbulsara]

Best thing is to ask the cable mfr as to what they recommend.

Asking the ferrule/lug mfr. for right application also would be helpful. You then you can post your findings here for everyone's benefit.