High-Energy Circuit Safety Precautions - Keithley 3700 Series User Manual

Section 5: Basic Digital Multimeter (DMM) Operation
TEMP: Temperature measurements from -200°C to 1820°C
CONT: Continuity testing using the 1k range
CAUTION

High-energy circuit safety precautions

To optimize safety when measuring voltage in high-energy distribution circuits,
read and use the directions in the following warning:
WARNING
When making measurements in high-energy circuits, use test leads that meet
the following requirements:
Test leads should be fully insulated.
Only use test leads that can be connected to the circuit (for example,
alligator clips, spade lugs, etc.) for hands-off measurements.
Do not use test leads that decrease voltage spacing. These diminish arc
protection and create a hazardous condition.
5-2
When using a switching module, do not exceed the maximum
signal levels of the module.
Dangerous arcs of an explosive nature in a high-energy
circuit can cause severe personal injury or death. If the
multimeter is connected to a high-energy circuit when set
to a current range or low resistance range, the circuit is
virtually shorted. Dangerous arcing can result even when
the multimeter is set to a voltage range if the minimum
voltage spacing is reduced in the external connections.
As described in the International Electrotechnical
Commission (IEC) Standard IEC 664, the Series 3700 is
Installation Category I and signal lines must not be directly
connected to AC mains.
Series 3700 System Switch/Multimeter User's Manual
3700S-900-01 Rev. C / July 2008