Extra flexible main lead

  • Thread starter Thread starter Alex Coleman
  • Start date Start date
Alex Coleman said:
Is silicon flex more flexible than regular PVC?
Click to expand...

I wouldn't think so; silicon isn't very flexible. That's why thermal stress
tends to cause power transistors' silicon dies to fail.

Tim (yes, I have to :-p)
 
I wouldn't think so; silicon isn't very flexible. That's why thermal stress
tends to cause power transistors' silicon dies to fail.

Tim (yes, I have to :-p)
Click to expand...

Quite right. Silicone flex isn't bad, though. Have some on the small
soldering iron.
 
Silicone rubber covering is MUCH more flexible, and stands higher
temperatures, but is more expensive and much less resistant to
abrasion, cutting and especially crushing. While it's rubbery, it
crumbles like a weak crystal under moderate pressure, wheras PVC
would be more ductile even at higher pressures. Both give off
harmful gasses if you heat them enough to burn. I think silicone
rubber might have a higher dielectric strength than similar
thickness on PVC, but I'm not sure.
Click to expand...


Ah, silicone not silicon!

And is it a form of rubber or is it just called "silicone rubber"
because it is silicone made to behave like rubber?

Interesting about how it crumbles.
 
Alex Coleman said:
Ah, silicone not silicon!

And is it a form of rubber or is it just called "silicone rubber"
because it is silicone made to behave like rubber?
Click to expand...

AFAIK, it's always rubbery. I would think heavily crosslinked silicones
could have pretty solid structure, but I've never heard of a hard or brittle
silicone product so I guess not.

Tim
 
Ah, silicone not silicon!

And is it a form of rubber or is it just called "silicone rubber"
because it is silicone made to behave like rubber?

Interesting about how it crumbles.
Click to expand...

http://en.wikipedia.org/wiki/Silicone
(I'm really beginning to like that Wiki)

I didn't know they could be hard plastics too..
They mention silly putty, which is a silicone, and an extreme example of
what I was getting at. I think many silicones have an abrupt change of
properties under impact either at speed or pressure. Cable covering has a
weak pressure resistance, silly putty has a poor speed resistance, and
either way what happens is they cease to move as a fluid elastic, and
will fracture like glass or crystal.
 
AFAIK, it's always rubbery. I would think heavily crosslinked silicones
could have pretty solid structure, but I've never heard of a hard or
brittle silicone product so I guess not.
Click to expand...

Yes - my oldest soldering iron with silicone lead which came with a Maplin
kit solder station must be well over 10 years old and the lead is still
fine despite mucho flexing over the years.
 
Is it possible to get more flexible 13 Amp mains lead to replace those
leads which hardly seem to bend?

I guess that these "inflexible flexes" are made of tough version of PVC
and contain and fewer but larger individual wires in the cores.

Presumably having fewer cores is a cheaper way to make a mains lead. is
this correct?
Click to expand...

I've seem mains cable (240VAC over here) that's super flexible. The
examples I've seen use silicone rubber sheathing (which is also
exceptionally heatproof, BTW) with cores made from many more & finer
strands than usual.
Looking at the RS electronics website, (which requires a login, so I
can't quote a URL), Beldon's CYSC03.00100 is probably the style of
cable you're looking for:
----------
A continental style flexible power control cable, commonly known as
‘CY‘ type. The fine stranding of the cores combined with the tinned
copper braid produces a cable with characteristics of a flexible mains
cable with the screening properties of a signal cable. This makes the
cable ideal for uses such as automated and robotic equipment where
screening is required and the equipment may be subjected to vibration
or movement.
technical specification

Conductors Annealed copper
Sheath PVC
Braid Tinned annealed copper
Outer sheath Grey PVC
Core colours
3 core Blue, Brown, Green/Yellow
4 core Blue, Brown, Black, Green/Yellow
5 core Blue, Brown, Black, Black, Green/Yellow
7 core Green/Yellow + 6 numbered

key characteristics

csa 0·75mm2 1mm2 1·5mm2 2·5mm2
Conductor size 24/0·2 32/0·2 30/0·25 50/0·25
Current rating (A) 6 10 16 20
Overall dia. (max.)
3-core 7·2 7·6 8·2 10·1
4-core - 8·2 9·5 -
5-core - - 10·3 12?·4
7-core - - 11·1 -

Voltage ratings :
between conductor and earth 300V
between conductors 500V
Current ratings:
For further details consult IEE Regulations 16th
Edition table 4H3
Temperature ratings:
Flexing -5°C to +70°C0. Stable -20°C to +70°C
 
I
Cables made in the far east are less flexible at normal UK ambient
temperatures, they are fine on hot days though.
Rubber cable is available but a lot more expensive than PVC.
Companies that install cold rooms use rubber because PVC is difficult to
handle at low temperatures.
Arctic grade PVC is a good compromise but is usually blue or yellow.
Silicon rubber cable is available in 0.5mm 3-core, it is usually used
for soldering irons and is very flexible.
What application did you have in mind?
 
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