No, but you can estimate it by some measurements. A few months ago I did this for BNC connectors, as there are no specs for BNC power dissipation (i.e., the actual power you can dissipate in the connector). The pins, sockets, and pin-to-socket connection's resistances will be down in the milliohm or sub-milliohm region. The limiter of the connection is probably the wire that is used in the connector, not the connector; this is the case with the typical RG-58/U coax used with BNC connectors. Get a constant current power supply and measure the temperature rise of the connector body with an IR thermometer as a function of current. Use your engineering judgment as to what's an acceptable temperature rise. For the BNC/coax, I decided that I would limit my BNC cables to 5 A continuous DC current, but would allow 10 A for short periods (say, a minute or two).
