White Paper

More Meaningful Connections
5 WHITE PAPER – VeriSafe
™
– Update to the NFPA 70E Standard
Voltage Indicator
A voltage indicator is an installed device that illuminates when voltage
is present; however, a voltage indicator can be unreliable. When lights
on the indicator are o, there could still be voltage if there is a hardware
failure, such as the indicator functioning abnormally or if the LEDs fail.
Improper installation of a voltage indicator or loose leads can cause the
voltage indicator to become disconnected from its source, resulting in
false or unreliable indications. Ultimately, voltage indicators do not meet
the requirements for Sections B, C, and D.
Absence of Voltage Tester (AVT)
An AVT diers from the previous devices discussed because it is a reliable
test device that uses active indicators. All AVTs use active indicators to
visually convey that voltage is not present. As an additional safety feature,
some testers such as the VeriSafe AVT incorporate voltage indicators to
show when voltage is present. Before the absence of voltage indicator
illuminates, the AVT verifies that it is installed properly, the tester is
installed properly, the tester is functioning properly, and neither AC nor
DC voltage is detected.
Table 1 is a side-by-side comparison on how well hand-held testers,
installed voltage meters, voltage indicators, and the VeriSafe AVT comply
with the requirements dictated in Exception 1.
Key features of an AVT
• Tests without exposure to
harmful voltages
• Self-contained; no need for
additional meters or tools
• Built-in pre-/post-verification
test
• Verification that the tester is in
contact with the circuit before
and after every test
• Tests for absence of AC and
DC voltage
• Tests phase-to-phase and
phase-to-ground
• Automated test sequence
• Active indication for absence
of voltage
• Safety functions meet safety
integrity level (SIL) 3 per IEC
61508
2
2
IEC 61508 Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems.