I am not familiar with the cord unit you tested then. (10A plug and adjustable CB). Was it an EVSE of some form ?
What was the date of your test and model / supplier of the unit ?
Did you test the cord with a production EV with the 'other half' of the J1772 system (assuming it was J1772) ?
Note. EV conversions can be upgraded to use full J1772 functionality. Looks like some folk in the US are already doing this.
http://www.ebay.com.au/itm/J1772-Active ... 3a7bcd1952
For clarity here, the 'in cord' unit that you refer to is not an EVSE of the form that is supplied with Mitsubishi iMiEV or Nissan Leaf.
( I've not examined the Volt unit yet )
These EV manufacturer supplied occasional use EVSE (made by Panasonic) use the J1772 system and do detect and protect users from numerous charging faults including earth issues. They respond with 'fault' light and will not power up the cable.
They DO NOT monitor connector temperatures ( potentially doing so is a good idea as you say) however they DO use plated pin 3 pin 15A Oz plugs, 2.5mmsq high flexibility heavy duty cable and suitable IP rated 20A J1772 plugs. Through this they draw a conservative 10A. So the very 'running at rated 10A on Oz 3 pin and need to monitor temperature' as you suggest is not quite the same issue !
Just another feature that helps with charging connector temperature rise.... Most EV chargers in production EVs are constant current on the AC input side (e.g. 10A) rather than the older constant current on DC output side chargers used in EV conversions. This reduces the risk of thermal runaway if a connector's contact resistance rises since the response of the older style chargers was to increase their current draw as the voltage sags in order to maintain their output power.
The full charging option (and the one recommended by EV manufacturers) is a hard wired wall mounted EVSE to obtain full 15A or 32A charging.
None of this comment is at all knocking conversions. It is just observation on the advancing technologies and a reminder to adopt best practices with our conversions.
Should we ask weber's question ?