June 2022
11
VeriSafe 2.0 AVT
Installation Considerations
This section provides guidelines for installing the 2 .0 AVT . It also addresses common application scenarios and describes best practices .
GENERAL INFORMATION
Before installing the AVT, identify all sources of electrical energy in the equipment . Install the AVT at the point in the circuit
where you would normally test for voltage . The AVT will only test for voltage at the point where it is installed . If there are multi-
ple energy sources or multiple test points, consider using multiple AVTs . Mark the test location on the yellow instruction label .
Apply this label to outside of enclosure near the indicator module . There should not be any circuit elements (ex . circuit breaker,
fuse, VFD, switch or similar control devices, etc .) installed between each pair of sensor leads . Although the absence of voltage
threshold is 3 .0 V, residual voltages should be less than 2 .7 V to ensure proper function .
EFFECT ON SHORT CIRCUIT CURRENT RATING (SCCR)
AVTs listed to UL 1436 are required to operate as a secondary circuit that is isolated from the circuit conductors by use of a
transformer, optical isolator, or limiting impedance, or other similar means . This is intended to reduce the risks of both electric
shock and thermal hazard . These isolation circuits allow very limited current flow, if any, through the AVT .
The VeriSafe 2 .0 AVT is suitable for use on circuits delivering up to 300,000 rms symmetrical A at 1000
V .
AVT sensor lead terminations should be made via a tap to the circuit conductor using connectors, terminal strips, or power
distribution blocks, etc . which are rated for the application . It is generally preferred to use connection methods that DO NOT
pierce or otherwise compromise the integrity of the conductor . Connectors that require conductors to be cut or spliced can be
used but may limit the SCCR .
USE OF OVERCURRENT PROTECTION
Installation of an AVT with overcurrent protection is neither required nor recommended . UL 1436 requires AVTs to be construct-
ed so that internal component failures will not expose the AVT to available short circuit currents from the main power supply
during normal operation and under single-fault conditions . The 2 .0 AVT uses high impedance to limit voltage and current flow
through the device to safe levels . In addition, the AVT has been tested to withstand transient overvoltage up to 8 kV .
If the AVT sensor leads are not longer than
10 feet, they can be treated as a feeder
circuit and do not require overcurrent
protection [NFPA 70:2020 240 .21(B)(1)(b)
Exception and CSA C22 .1:21 14-100(b)]
In certain regions and countries, additional overcurrent protection is required to
conform to standards such as AS/NZS3000 . Do not install multiple sensor leads
on one overcurrent protection device . Sensor lead pairs must not be electrically
connected in the event that the overcurrent protection is in the open state . Do not
install overcurrent protection on the two green ground leads .
GND
L3
L2
L1
DISCONNECT
VeriSafe Isolaon
Module
L1 L1
L2
L3
L2
L3
PE
GND
L3
L2
L1
DISCONNECT
VeriSafe Isolaon
Module
L1 L1
L2
L3
L2
L3
PE
F1 F2
F3 F4
F5 F6
GND
L3
L2
L1
DISCONNECT
VeriSafe Isolaon
Module
L1 L1
L2
L3
L2
L3
PE
F1
F2
F3
