Using 3 core flex instead of twin and earth?

I've got some new three-core flex. 2.5mm squared.
It's the sort of thing you would use for an extension lead except I've not
seen any that thick before (cable is about the same diameter as my little finger).
I can't see any reason why it shouldn't be used to extend my ring main but I've not seen it used for that purpose (possibly because it would be much more expensive than twin core and earth).
Does anyone know of a reason why I shouldn't use it please?
Thanks very much,
Paul
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

There's no prohibition in the regs on using flex where solid core cable would normally be used. The current rating is slightly less, possibly due to less surface area, and there are no published ratings for flex buried in walls, etc. which would make such use questionable as you can't point to a table in the regs which indicates it's OK. Published flex current ratings are for use in free air or against one surface (and there are also published ratings for multiple layers wound on a spool, not relevant here).
Another issue is making connections at terminals. Trying to mix flexible and solid core conductor in the same terminal invariably fails. Flexible conductors should have a bootlace ferrule crimped or soldered on in this case. (Don't just solder the strands into one solid piece without using a ferrule.)
Your 2.5mm flex is worth much more than 2.5mm T&E, so I suggest you sell it on ebay and buy the right T&E cable, which will be very much easier to use.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.