involved.

(C) Marking. Equipment shall be marked to show the environment for which it has been evaluated. Unless otherwise specified or allowed in (C)(6), the marking shall include the information specified in (C)(1) through (C)(5).

(1) Class. The marking shall specify the class(es) for which the equipment is suitable.

(2) Division. The marking shall specify the division if the equipment is suitable for Division 2 only. Equipment suitable for Division 1 shall be permitted to omit the division marking.

FPN: Equipment not marked to indicate a division, or marked "Division 1" or "Div. 1," is suitable for both Division 1 and 2 locations; see 500.8(B)(2). Equipment marked "Division 2" or "Div. 2" is suitable for Division 2 locations only.

(3) Material Classification Group. The marking shall specify the applicable material classification group(s) in accordance with 500.6.

Exception: Fixed luminaires marked for use only in Class I, Division 2 or Class II, Division 2 locations shall not be required to indicate the group.

(4) Equipment Temperature. The marking shall specify the temperature class or operating temperature at a

40°Cambient temperature, or at the higher ambient temperature if the equipment is rated and marked for
an ambient temperature of greater than 40°C. The temperature class, if provided, shall be indicated using the temperature class (T Codes) shown in Table
500.8(C). Equipment for Class I and Class II shall be
marked with the maximum safe operating temperature,
as determined by simultaneous exposure to the
combinations of Class I and Class II conditions.

Exception: Equipment of the non-heat-producing type, such as junction boxes, conduit, and fittings, and equipment of the heat-producing type having a maximum temperature not more than I00°C shall not be required to have a marked operating temperature or temperature class.

FPN: More than one marked temperature class or operating temperature, for gases and vapors, dusts, and different ambient temperatures, may appear.

Table 500.8(C) Classification of Maximum Surface

Temperature

Maximum Temperature

Temperature Class

°c °F (T Code)

450 842 Tl

300 572 T2

280 536 T2A

260 500 T2B

230 446 T2C

215 419 T2D

200 392 T3

180 356 T3A

165 329 T3B

160 320 T3C

135 275 T4

120 248 T4A

100 212 T5

85 185 T6

(5) Ambient Temperature Range. For equipment rated for a temperature range other than -25°C to +40°C, the marking shall specify the special range of ambient temperatures in degrees Celsius. The marking shall include either the symbol 'Ta" or "Tamb."

FPN: As an example, such a marking might be "-30°C < Ta < 440°C."

(6) Special Allowances.

(a) General-Purpose Equipment. Fixed general- purpose equipment in Class I locations, other than fixed luminaires, that is acceptable for use in Class I, Division 2 locations shall not be required to be marked with the class, division, group, temperature class, or ambient temperature range.

(b) Dusttight Equipment. Fixed dusttight equipment,

other than fixed luminaires, that is acceptable for use in
Class II, Division 2 and Class III locations shall not be
required to be marked with the class, division, group,
temperature class, or ambient temperature range.

(c) Associated Apparatus.