The reason for my enquiry was that your manual does not say that the 8500 input is isolated in the OFF state. If this is not the case, it would still be possible to damage the 8500 by exceeding the rated voltage.
I wanted to be sure that the over-volatge protection is not intended to protect external circuitry from overload by turning OFF the 8500, and that instead, it will protect the 8500, even if its rated input voltage is exceeded.
Reply
When the input is off, the measurement range is still the rating voltage of the machine, if the input exceed the rating voltage, then the Over Voltage Protection will work.
If the input voltage exceed too much, it may damage the electronic load.