Automation Canada - Cables & Connectors Issue - 40

CASE STUDY: GROUND LEAD FAILURE
Situation:
Worker approaches the enclosure and the disconnect switch for
the 480V power source is in the OFF position. The disconnect
switch has failed with one phase (L1) in the closed position (L2, L3
are open). The ground leads of the devices are NOT connected to
ground because of an improper installation or termination failure.
The worker applies a lock. Following safety procedures, the
worker performs an absence of voltage test with the electrical
enclosure closed using a permanently mounted device.

Permanently
Mounted Device

Failure Mode

Potential Cause

System State

Ground lead(s)
are NOT
connected to
ground

Voltage Test
Station (VTS)

C A N A D I A N A U TO M AT I O N

Improper
installation or
termination failure

Disconnect is in
the OPEN/OFF
position with L1
energized

Red wired are
energized at 480V
L1 L2 L3

Test
Portal

Front of
Door

VeriSafeTM Absence
of Voltage Tester

Detection

YES - the AVT will detect open
ground (or phase) lead(s) and
communicate the installation
of sensor leads is not verified

Absence of
Voltage
Tester
ester (AVT)
( VT)
Test
Portal

Ground leads are
not connected

Failure Effect
AVT will detect
open ground lead(s)
and communicate
installation is the
reason the absence of
voltage test cannot be
confirmed

NO - voltage measurement
results in zero voltage when
voltage is present

NO - the L1 LED for the
voltage indicator will not be
illuminated and measurement
results in zero voltage when
voltage is present

Worker erroneously
considers electrical
enclosure as
deenergized

Incident Consequence

None - Incident
Avoided

Worker opens
equipment while
energized
* Probable shock or
* Equipment
damage is likely

VOLUME 3, ISSUE 2

40



Automation Canada - Cables & Connectors Issue

Table of Contents for the Digital Edition of Automation Canada - Cables & Connectors Issue

Automation Canada - Cables & Connectors Issue - 1
Automation Canada - Cables & Connectors Issue - 2
Automation Canada - Cables & Connectors Issue - 3
Automation Canada - Cables & Connectors Issue - 4
Automation Canada - Cables & Connectors Issue - 5
Automation Canada - Cables & Connectors Issue - 6
Automation Canada - Cables & Connectors Issue - 7
Automation Canada - Cables & Connectors Issue - 8
Automation Canada - Cables & Connectors Issue - 9
Automation Canada - Cables & Connectors Issue - 10
Automation Canada - Cables & Connectors Issue - 11
Automation Canada - Cables & Connectors Issue - 12
Automation Canada - Cables & Connectors Issue - 13
Automation Canada - Cables & Connectors Issue - 14
Automation Canada - Cables & Connectors Issue - 15
Automation Canada - Cables & Connectors Issue - 16
Automation Canada - Cables & Connectors Issue - 17
Automation Canada - Cables & Connectors Issue - 18
Automation Canada - Cables & Connectors Issue - 19
Automation Canada - Cables & Connectors Issue - 20
Automation Canada - Cables & Connectors Issue - 21
Automation Canada - Cables & Connectors Issue - 22
Automation Canada - Cables & Connectors Issue - 23
Automation Canada - Cables & Connectors Issue - 24
Automation Canada - Cables & Connectors Issue - 25
Automation Canada - Cables & Connectors Issue - 26
Automation Canada - Cables & Connectors Issue - 27
Automation Canada - Cables & Connectors Issue - 28
Automation Canada - Cables & Connectors Issue - 29
Automation Canada - Cables & Connectors Issue - 30
Automation Canada - Cables & Connectors Issue - 31
Automation Canada - Cables & Connectors Issue - 32
Automation Canada - Cables & Connectors Issue - 33
Automation Canada - Cables & Connectors Issue - 34
Automation Canada - Cables & Connectors Issue - 35
Automation Canada - Cables & Connectors Issue - 36
Automation Canada - Cables & Connectors Issue - 37
Automation Canada - Cables & Connectors Issue - 38
Automation Canada - Cables & Connectors Issue - 39
Automation Canada - Cables & Connectors Issue - 40
Automation Canada - Cables & Connectors Issue - 41
Automation Canada - Cables & Connectors Issue - 42
https://www.nxtbook.com/kerrwil/AutomationCanada/automation-canada-machine-safety
https://www.nxtbook.com/kerrwil/AutomationCanada/auto-tuning-and-variable-frequency-drives
https://www.nxtbook.com/kerrwil/AutomationCanada/automation-canada-automation-in-2021
https://www.nxtbook.com/kerrwil/AutomationCanada/AutomationCanadaMachineSafetyMay2021
https://www.nxtbook.com/kerrwil/automationcanadaquarterly/AutomationCanadaV2I5
https://www.nxtbookmedia.com