Which wire to use

I have a resistance soldering unit which has the wires for the soldering (output) end of things attached to 4mm banana plugs. This allows for convenient selection of heat settings. Unfortunately the wires are a little short and could be usefully extended by 6 to 12 inches. The wires are 4mm measured over the insulation and inside the insulation are composed of many very fine copper strands which gives excellent flexibility. The nearest I have seen to it is speaker cable. The unit is rated at 240V and is fused at 1 amp on the mains side. There is no information regarding the output side. Before I start to search on-line, what is this sort of wire called, please?

Hi Mick,

I think what you need is multi stranded wire. It's a little difficult knowing the size from measuring the diameter as cable is measured using cross sectional area of the conductors. At a guess I'd say it was 2.5mm². Normally a unit like this would have some info printed on it, maybe on the base, detailing the output. A photo or model number might help.

Also, if you extend the wires you may change the resistance and affect the operating parameters.

Ed.

I would have thought one of the silicon insulated wires of the type found on electrical test meters would do the job. Hard to say from your outside dimensions as to the wire size but as Ed says 2.5mm2 would seem about right.

J

EDIT, something like this 2.5mm" 32Amp

Edited By JasonB on 06/01/2015 15:17:23

Mick,

The output should be very low voltage and high current ... If I recall correctly, mine switches from about 1.8 volts up to about 4 volts.

Have a look at American Beauty for useful info.

MichaelG.

Edited By Michael Gilligan on 06/01/2015 15:09:44

Normal Speaker Cable is not suitable .. you need something that will carry 20-30 Amps at 0-5 or so volts.

Not at home at moment so cannot look up what to use ... some form of High Current Extra-Flexible cable I suspect.

Dave

I don't think 4mm banana plug will carry 20 amps for long, nor do I think they can accommodate thick wire either. Speak cable is very supple and comes in several sizes, so I think that's the route to go. The only reservation is will the insulation stand the heat. Its not costly for a small amount, so give it a try. I have some on my big battery charger, with an identification tape on the + lead both ends, its been on years. ted

Darn you MichaelG

You are now responsible for me being side-tracked again!

That link to the American Beauty has given me an idea for my Graskop RSU, thanks.

Any thoughts on making the tweezer/pliers?

 

Geoff - I WILL try not to go off track, but...

I don't think 4mm banana plug will carry 20 amps for long,

That was going to be my next question. Is there a better form of 4mm plug?

Mick

.

Geoff,

Last time I browsed around the American Beauty site [and their YouTube videos], I was reminded how "Cottage Industry" the tweezers/pliers looked [i.e. very reproducible] ... I haven't tried making any yet; but some Phosphor Bronze strip, and some Tufnol, should get you off to a great start.

MichaelG.

.

Edit: I'm pretty sure that most of use could make something along these lines [or these]

Edited By Michael Gilligan on 06/01/2015 17:01:28

Edited By Michael Gilligan on 06/01/2015 17:03:50

CPC do 4mm banana plugs rated up to 50 amps...

The vast majority are rated about 24-30A so they should be fine.

Yes, I was surprised...

Neil

.

Mick,

Some of the 4mm sockets are also screw-down "binding posts" with a cross hole.

... use these with either bare wires or a ring or 'U' terminal on the wire.

MichaelG.

.

Not the cheapest; but here is an example

Edited By Michael Gilligan on 06/01/2015 16:54:42

.

Methinks the rating is improved by the large pinch of salt.

MichaelG.

Not really, over 12mm of 4mm diameter plug the potential total contact area is about 150 mm^2, Assume just 10% contact area and that's 15mm^2 compared to, say, 4mm^2 or less on a typical 240V 13A switch.

Neil

.

Sorry, forget the ring terminal ... the tops don't come off

... use these with either bare wires or a ring or 'U' terminal on the wire.

MichaelG.

.

P.S. if you must use plugs, I suggest this multi-spring style.

Edited By Michael Gilligan on 06/01/2015 17:44:23

Edited By Michael Gilligan on 06/01/2015 17:57:10

for Geoff:

14 swg Nichrome wire [for tweezer tips] is readily available on ebay

MichaelG.

Edited By Michael Gilligan on 06/01/2015 18:09:10

Hi Mick,
This wire from Maplin code XR57M will probably be suitable.

Les.

Thank you gentlemen for your usual comprehensive assistance and pointers to where to get the stuff. Very much appreciated. Meanwhile I look forward to the development of those tweezers!

Mick

Just dug my transformer out of the garden shed

... they both need a bit of cosmetic attention.

Note the current rating, and the 7/16" diameter output terminals.

Model Number is P.05 ... but I can't find a Manufacturer's name.

MichaelG.

.

Mick,

I have just found this excellent DIY page

MichaelG.

Cripes Michael,

You could probably use that as an arc welder on 25V...

Neil