I've searched through a lot of threads regarding this and found some answers, however, the data sheet I am provided has some information which is causing some confusion.

I have a switch with the following rating:

  • Operation - AC15: 250VAC/6A, DC13: 250VDC/0.6A
  • Electrical Capacitor - Max insulation voltage 600VAC, max thermal current 10A
  • Contact resistance - Max 50mohms

I am trying to determine the maximum current rating at 12VDC and 24VDC. Based off of some posts, most say to contact the manufacturer (which has gone unanswered). Others say that the max current will be 0.6A at any DC voltage. However, I have not seen anyone comment on the "max thermal current 10A" and I am wondering if this is the current which should not be exceeded any any voltage.

Thank you!

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    \$\begingroup\$ Need someone that speaks whatever language that is.. Me thinks ELectrical Capacitor is a bad translation. and ya, I was going to mention that too @brhans ;) \$\endgroup\$ – Trevor_G Nov 28 '17 at 18:26
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    \$\begingroup\$ @Trevor - A datasheet which doesn't make sense is arguably worse than no datasheet at all. I'd probably be looking for a different switch. \$\endgroup\$ – brhans Nov 28 '17 at 18:28
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    \$\begingroup\$ Notice the 250V.AC current is only 6A in Chinese..16 in English.. DO they have bigger electrons in China or wherever this is from? \$\endgroup\$ – Trevor_G Nov 28 '17 at 18:31
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    \$\begingroup\$ Good spot @Trevor, that makes more sense with the derating too, usually about 10x. \$\endgroup\$ – awjlogan Nov 28 '17 at 18:34
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    \$\begingroup\$ Or, more likely given the right column, something like "electrical limits" \$\endgroup\$ – The Photon Nov 28 '17 at 19:31

That is a very bad spec sheet with errors and translation issues. As such it is difficult to say what some of those numbers mean if you can not read the original language.

However, when it comes to switching DC, it the relay does not specifically say a current at a lesser voltage, or include some form of graph that shows you safe operating currents at different voltages for DC, you need to use the value shown.

It seems intuitive that if it can withstand 600mA as 250V DC, then maybe it should be able to handle 6A at 25V DC.

However this in not the case.

An electrical arc will form is there is sufficient current and voltage to break through a particular air gap. Obviously the bigger the gap, the more V & I you need to create an arc. However, the converse is also true, if the gap is very small, you need very little current and voltage.

When they first begin to open, the gap is infinitesimal, as such even a very small current will be enough to spark an arc. Once lit, the duration of the arc will depend on the makeup of the switch arrangement.

As such, without any other information to go on, you need to assume 600mA DC is all you can switch with this device and have it operate as guaranteed in the spec-sheet.

As for the 10A number, I too would assume that is the max you should pass through it without switching. However, that is a VERY DANGEROUS number to play with. Inadvertent switching can have some very serious consequences.


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