Keithley 2001 Quick Reference Manual page 5

states that a shock hazard exists when voltage levels greater
than 30V RMS, 42.4V peak, or 60VDC are present. A good
safety practice is to expect that hazardous voltage is
present in any unknown circuit before measuring.
Users of this product must be protected from electric shock at
all times. The responsible body must ensure that users are pre-
vented access and/or insulated from every connection point. In
some cases, connections must be exposed to potential human
contact. Product users in these circumstances must be trained
to protect themselves from the risk of electric shock. If the cir-
cuit is capable of operating at or above 1000 volts, no conduc-
tive part of the circuit may be exposed.
As described in the International Electrotechnical Commis-
sion (IEC) Standard IEC 664, digital multimeter measuring
circuits (e.g., Keithley Models 175A, 199, 2000, 2001, 2002,
and 2010) are Installation Category II. All other instruments'
signal terminals are Installation Category I and must not be
connected to mains.
Do not connect switching cards directly to unlimited power
circuits. They are intended to be used with impedance limited
sources. NEVER connect switching cards directly to AC
mains. When connecting sources to switching cards, install
protective devices to limit fault current and voltage to the card.
Before operating an instrument, make sure the line cord is
connected to a properly grounded power receptacle. Inspect
the connecting cables, test leads, and jumpers for possible
wear, cracks, or breaks before each use.
For maximum safety, do not touch the product, test cables, or
any other instruments while power is applied to the circuit
under test. ALWAYS remove power from the entire test sys-
tem and discharge any capacitors before: connecting or dis-
connecting cables or jumpers, installing or removing
switching cards, or making internal changes, such as install-
ing or removing jumpers.
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