II - DCE FEL ČVUT v Praze

Table 1-8 Working on systems to type of protection: EEx de [ib] T5 .. T6, continued
Type of
protection of
apparatus used in
system
Mechanical Configuration of an Automation System with SIMATIC S7 Ex Modules
Type of work to
be carried out
EEx d Zone 1 Zone 2
Opening the
housing, Ex d
housing only
Connecting/
disconnecting
lines
Current, voltage
and resistance
measurement
I/O Modules with Intrinsically-Safe Signals
C79000-G7076-C152-04
Work within Additional
requirements and
notes
Prohibited Allowed if no risk
of explosion
Not allowed
unless in
de-energized state
Allowed if no risk
of explosion
Work not possible Allowed if no risk
of explosion
Soldering Prohibited Allowed in
de-energized state
if soldering
temperature lower
than ignition
temperature
Apparatus in
flameproof
enclosure are no
longer protected
against explosion
if housing is
opened
See also “S7-300, M7-300, ET 200M Automation Systems Principles of
Intrinsically-Safe Design“ Manual, Chapter”Installation, Operation and
Maintenance of Electrical Systems in Hazardous Areas”, Table “Information
for work to be carried out on explosion-protected apparatus” .
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