> My question is this: What is a reasonable/acceptable upper limit for
> maximum exterior surface temperature given these circumstances?

> Is there an accepted specification(s) for something like this?

> I am thinking maybe 60 deg C........?

Informal answer only:
I'd feel that 60C was too hot.
55C is what most people can just bear to immerse their hand in and
hold it there. A surface at 60C won't burn you with an occasional
touch, but if you rested against it more than momentarily it would
start at uncomfortable and end up at unbearable.

Apart from the touch issues, unless I was explicitly told that a
device should get that hot I'd suspect that it may be faulty or badly
designed - depending on what it was. eg if it was a solder bath,
toaster oven, kettle etc it would be entirely fine.
BUT I'd not expect to be able to safely touch such things anyway so
hotter would be OK as long as liability issues were met.

       Russell
--=20
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