On 01 Jun 2007, wrote:

On 1 Jun, 12:13, Palindrome wrote:
Bob Mannix wrote:
wrote in message
roups.com...

Coleman wrote:

I am in the UK. I want to ask for info about joining 3-core
mains flex on an appliance that may have to carry up to 3,000
Watts.

I usually extend the mains flex by soldering but the finished
join is too bulky when winding the flex or pulling it around a
corner.

When I make my 3 joints I slightly offset each one so that it
is not beside another one. This helps make a slimmer overall
joint but it makes for a longer joint (about 2.5 to 3 inches)
and with insulating tape it is still too bulky.

(A) Is it safe to use heat shrink insulating tubing for each
join and have each join beside the other? Then I might use a
single layer of insulating tape to bind over and protect the 3
joins.

(B) Or is there some widget which can help with this? Perhaps
a small moulding which is made up of three very small metal
tubes held by moulded plastic to be close together but not
touching. I could put a wire into each end of a metal tube and
then solder the wires into it. (It's just an idea.)

Any info?

http://wiki.diyfaq.org.uk/index.php?...ed_Flex_Joints

But that is about twisted flex joints (the key is in the name
) ) rather than soldered joints, which is what the OP was
talking about. Hardly ideal but still not twisted flex joints
and therefore not subject to the dangers described in the
article.

I would suggest that soldered joints covered with normal heat
shrink and insulating tape, "lack tensile strength, abrasion
resistance, general robustness, spillproofness (they can make a
small spill live), good insulation, petproofness & small
childproofness."

The marginal advantage of soldering the joints has to be balanced
against the greater risk of failing during flexing, as the
soldered joint will form a flexure discontinuity and stress
points.

Of course, soldering with acid flux would be an even greater
problem.

--
Sue

I also thought it was pretty obvious what also applied to soldered
joints. Solder is weak stuff too, though I've not seen any
significant failures from soldering pretwisted flex (at LV). But
not everyone twists enough before soldering.



ISTR there was a time when the different twists had their own names.
Maybe they still do.

Wasn't something like "Western Roll" one such name???