GENERAL INFORMATION
1-5 November 1999
Part No. 001-7780-500
tion. When electricalequipment is given this rating, the
equipment is considered incapable of releasing suffi-
cient electrical and thermalenergy under normal oper-
ation or specified fault conditionsper the testing
standard to cause ignitionof a specific flammable or
combustible atmosphere in its most easily ignitedcon-
centration. In other words, this transceivershould not
cause a fire or explosion when used in certain flamm a-
ble atmospheres.
Fault - A defect or electrical breakdown of an yc ompo-
nent, spacing, or insulation which alone or in combina-
tion withother faults may adversely affect the electrical
orthermal characteristics of the intrinsicallysafe circuit
(for example, a shorted transistor).
1.10.3 POSSIBLE IGNITION SOURCES
When a transceiver is checked by Factory
Mutual, possible sources of ignition arechecked.
These sources may be electrical (spark) or thermal
(heat). The following could be sources of spark
ignition:
•Discharge ofa capacitive circuitby a fault such as a
short circuit.
•Interruption of an inductive circuit.
•Intermittent making or breaking of a resistive
circuit.
•Hot-wire fusing.
The following could be sources of thermal
ignition:
•Heating of a small-gauge wire or PC board trace.
•High surface temperature of components.
1.10.4 INTRINSICALLY SAFE AND
NONINCENDIVE RATINGS
This transceiver is ratedintrinsically safe for
some types of hazards and nonincendive for other
types of hazards. An intrinsically safe rating ap plies to
operation in Division 1 areas,and a nonincendive
rating applies to operation in D ivision 2 areas (see
next section). The differencebetween these ratings is
as follows:
The intrinsically safe rating is a higher rating
because more severe conditions must be met. Tobe
approved for this rating,the transceiver must not cause
ignition of a particular atmosphere if two of the faults
specified in the testing procedure occur.In other
words, it must be able to withstand two simultaneous
unrelated breakdowns without causing ignition.To
receive a nonincendive rating, the transceiverneeds to
withstand only a single fault without causing ignition
of a particular atmosphere.
1.10.5 CLASSIFICATION OF HAZARDOUS
AREAS AND ATMOSPHERES
Introduction
This transceiver has been submitted for approval
to operate in the followinghazardous atmospheres and
areas. Contact your sales representativeor refer to the
label on the back of the trans ceiver to determine the
specific atmospheresand areas for which approval was
obtained.
Intrinsically Safe - Class I, II, an dI II, Division 1,
Groups C, D, E, F,and G.
Nonincendive - Class I, Division 2, Groups A, B, C,
and D.
TemperatureCode - T3C
The meanings of these Class, Division, and
Group designations are as follows.
Atmosphere Classification (Class/Group)
For the purposes of testing and approval, various
atmospheric mixtures have been grouped on the basis
of their hazardous characteristics.Equipment is
approved for a class of materialand also for the
specific gas, vapor, or dust in thatclass. Class I mate-
rials include gases and vapors, and Class II materials
include combustible dusts. The variousclasses and
some specific groups of gasesin each are shown in
Tabl e 1-2.
Area Classification (Division)
Areas are either Division 1, 2, or 3 as shown in
Table 1-3. Since a Division 1 area is considered the
most hazardous, a transceiver approvedfor a specific
Division 1 area can also be used in the same Divis ion
2 Class/Group.