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0.5mm2 = 3A, 0.5mm2 = 10A

I'm shopping for wire to use with 0.156" Molex connectors and I'm finding things which leave me perplexed. For instance,

Farnell ref. 140345 : Pro Power MC16/0.2 TYPE 2

Farnell ref. 584990 : Pro Power CBBR0156

Both are said to be 0.5mm2, 16/0.2mm. But while 140345 is rated for 3A, 584990 is rated for 10A. WTF ?

The only difference I can see is that 140345 is tinned and

584990 is not. But how would not tinning allow 3.33 times as much current ? Is there something I don't know about cables ?

Oh and the outer diameters differ too : 140345 is 1.6mm, 584990 is 2.6mm.

--
André Majorel 
(Counterfeit: rosifohar@aerogene.com femovyh@rifle.com)
"La presse doit diffuser des idées saines." -- Serge Dassault,
propriétaire de la Socpresse.
Reply to
Andre Majorel
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"Andre Majorel" a écrit dans le message de news: snipped-for-privacy@atc5.vermine.org...

André,

unless there's a typo (I didn't checked, so you should), what characterizes the current capability of a wire is :

- its working temperature (may vary, depending on the insulation material and the allowed ambiant temperature range)

- its dissipation capability.

The former is obvious and the latter depends on the insulation Rth and diameter. While increasing the insulation diameter increases the conductive heat resistance, it also increases the external convective surface, thus diminishing the convection resistance. Both resistances are added and for a given insulating material, there's an optimum external diameter.

Your 10A cable benefits probably from both points.

--
Thanks,
Fred.
Reply to
Fred Bartoli

Interesting. In both cases, the insulation is PVC.

Thanks.

--
André Majorel 
(Counterfeit: ovoz@wealthy.com gur@sewerage.com)
"La presse doit diffuser des idées saines." -- Serge Dassault,
propriétaire de la Socpresse.
Reply to
Andre Majorel

Hello Andre,

10amps over a 0.5sqmm wire would give me the goose pimples. I guess the fire marshall wouldn't like that either. I remember that some times ago the VDE requirement for short runs was 1.5sqmm for 16amps and many people (including me) consider even that marginal.

Regards, Joerg

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Reply to
Joerg

Joerg schrieb:

Additionally, these specs might be related to different environmental conditions, i.e. single straight wire vs. many (close) wires, different ambient or wire temperature, etc. You'd have to check the detailed data sheets from both manufacturers...

Besides that, in your application with the Molex connectors the current handling capability does not only depend on the cable, but also on the connector contact itself - which more often is the limiting factor.

--
Dipl.-Ing. Tilmann Reh
http://www.autometer.de - Elektronik nach Maß.
Reply to
Tilmann Reh

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