Brochure/Catalogue

Types of Protection
T Hazardous areas guide
Types of protection for electrical equipment
in explosive gas atmospheres
Type of
protection
Symbol Main application Norm
increased
safety
eb junction boxes, control stations for installing
Ex-components (with a different type of
protection), squirrel-cage motors, light ttings
IEC 60079-7
EN 60079-7
ISA 60079-7
ameproof
enclosures
db switchgears, control stations, indicating
equipment, control systems, motors,
transformers, heating equipment, light ttings
IEC 60079-1
EN 60079-1
ISA 60079-1
pressurized
enclosures
pxb
pyb
pzc
switchgear and control cabinets, analysers,
largemotors
IEC 60079-2
EN 60079-2
ISA 60079-2
intrinsic
safety
ia
ib
ic
instrumentation technology, eldbus
technology, sensors, actuators
[Ex ib] = associated electrical apparatus –
installation in the safe area
IEC 60079-11
EN 60079-11
ISA 60079-11
intrinsically safe systems IEC 60079-25
EN 60079-25
FISCO: eldbus intrinsically-safe concept IEC 60079-27
EN 60079-27
ISA 60079-27
oil immersion ob transformers, starting resistors IEC 60079-6
EN 60079-6
ISA 60079-6
powder
lling
qb sensors, display units, electronic ballasts,
transmitters
IEC 60079-5
EN 60079-5
ISA 60079-5
encapsu-
lation
ma
mb
mc
switchgear with small capacity, control and
signalling units, display units, sensors
IEC 60079-18
EN 60079-18
ISA 60079-18
type of
protection
“n”
nAc
nCc
nRc
all electrical equipment for Zone 2
nA = non-sparking device
nC = sparking devices and components
nL = energy limited apparatus
nR = restricted breathing enclosures
IEC 60079-15
EN 60079-15
ISA 60079-15
optical
radiation
op_a
op_b
op_c
op is = inherently safe optical radiation
op pr = protected optical radiation
op sh = optical radiation interlock
IEC 60079-28
EN 60079-28
Types of protection for electrical equipment
in explosive dust atmospheres
Type of
protection
Symbol Main application Norm
protection by
enclosures
ta
tb
tc
switchgear, control stations, junction boxes,
control boxes, motors, light ttings
IEC 60079-31
EN 60079-31
ISA 60079-31
pressuri-
zation
pb
pc
switchgear and control cabinets, motors IEC 60079-2
EN 60079-2
ISA 60079-2
intrinsic
safety
ia
ib
ic
instrumentation technology,
eldbus technology, sensors, actuators
[Ex ib] = associated electrical apparatus
– installation in the safe area
IEC 60079-11
EN 60079-11
ISA 60079-11
encapsu-
lation
ma
mb
mc
switchgear with small capacity, control and
signalling units, display units, sensors
IEC 60079-18
EN 60079-18
ISA 60079-18
W
W.8
Technical appendix
2712630000