The following SAFETY PRECAUTIONS should be observed when using an ohmmeter.
Deenergize and discharge the circuit before connecting an ohmmeter.
Do not apply power while measuring resistance.
Switch ohmmeters OFF, if a setting is provided, or to the highest range and remove the meter
leads from the meter when finished measuring resistance.
Adjust the ohmmeter after changing ranges and before measuring resistance.
A MEGOHMMETER (MEGGER) is used to measure very large resistances, such as the insulation
of wiring. To use a megger, isolate the resistance being measured from other circuits, connect the meter
leads, turn the hand crank, and note the meter indication. Normal insulation will indicate infinity.
The following SAFETY PRECAUTIONS should be observed when using a megger. Use meggers
for high-resistance measurements only.
Never touch the test leads while the handle is being cranked.
Deenergize and discharge the circuit completely before connecting a megger.
Disconnect the item being checked from other circuitry, if possible, before using megger.