I'm looking to find the maximum current rating that a H.FL75 cable can handle. Particularly this cable...


However, I cannot seem to find any mention of it on any internet search.

Does anyone here happen to know it?

Thank you in advance.

  • 1
    \$\begingroup\$ I don't think you have any choice but to contact the manufacturer. \$\endgroup\$ Apr 24, 2021 at 17:20
  • \$\begingroup\$ Thank you Elliot \$\endgroup\$ Apr 24, 2021 at 18:07

1 Answer 1


You have two limitations: rated current for inner conductor and that for connector. If you can get the cross section of the inner conductor, then you can calculate/estimate it. Of course a third factor is the environmental temperature.

Connectors of the snap-in type where the electric contact is good can handle large currents. A bit of attention should be give to the junction conductor-pin, but being an assembly done at a factory ad not home made, is surely well assembled and robust.

If you need just an idea of which rating you should use to stay safe, you can think that 0.5A ca flow continuously and 1A should be also compatible. Thing e.g. of GPS applications: there are miniature cables and connectors, the GPS is supplied through them and a 500 mA current is not impossible under poor coverage conditions.

Of course my talk is not a accurate estimate, that is not possible without a lot of details that in the datasheet seem to be missing.

  • \$\begingroup\$ Connector resistance is 30mOhm total (20m inner, 10m outer) so at 1A you could expect a 30mV drop and thus 30mW heat output, which seems reasonable. The inner core of the coax is likely to be around 32AWG and so 500mA is a sensible maximum current, with 0.54 ohm/metre resistance. The datasheet you linked to doesn’t appear to specify the cable though. \$\endgroup\$
    – Frog
    Apr 24, 2021 at 22:29
  • \$\begingroup\$ 30mV is fine and would dissipate 30mW @1A; so in reality you could afford more current if it were only for that. Then consider also that after some insertions and extractions, wearing of surface makes the contact resistance increase: connectors like these are usually rated for 50 or 100 operations. \$\endgroup\$
    – andrea
    Apr 24, 2021 at 22:34

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