Key Digital ES381 - Manual (Page 28)

4.4 Performance
4.4.1 Safety Data and Maximum Ratings
Important Safety Precautions
Always observe these when using the USBcount50
The USBcount50 contains no user serviceable parts inside.
Do not open the plastic housing.
There may be lethal voltages inside the plastic housing. Do
not use the instrument if the housing is damaged or is poorly
fitting. In such a case do not connect anything to the
USBcount50 to avoid a hazard. The USBcount50 will have
to be repaired or replaced in such a situation.
Do not exceed the maximum ratings listed below.
Never use the instrument if it becomes damp for any reason.
This includes situations were condensation has formed on
the unit due to sudden temperature or humidity changes.
Never use test leads that are damaged or have insufficient or
incomplete insulation.
Never allow any conductive part of any test lead to contact
the host computer ground. Doing so will bypass the safety
isolation in the USBcount50 and could cause a lethal hazard.
Remember that the isolation is between the BNC and the
USB connectors. The BNC is, of course, at the same
potential as the test lead ground clip to which it is connected.
Be careful when measuring hazardous voltages not to touch
the BNC connector ground for this reason.
Only use the shorter length stack connector in the bottom
counter of the stack, and if using a single counter, don’t fit
any stack connector at all. This is to avoid touching the
contacts
Elan Digital Systems Ltd. 28 USBcount50 USER’S GUIDE Iss1