COOPER IND., BUSSMANN DIVISION
APPLICATION ENGINEERING
P.O. BOX 14460
ST. LOUIS, MO 63178
PHONE: (636) 527-1270
FAX:
(636) 527-1607
To Whom It May Concern:
In order for fuses to be rated for Class 1 Div 2, they must first meet the requirements specified in Article
501.115 from the 2008 NEC standard. In regards to the indicating options on the fuse, the striker pin is
not permitted due to the ability to create a spark. The fuses should be applied with non-indicating fuse
holders to meet the Class 1 Div 2 requirements for use in hazardous areas.
501.115 Switches, Circuit Breakers, Motor Controllers, and Fuses.
(A) Class I, Division 1. In Class I, Division 1 locations, switches, circuit breakers, motor controllers, and
fuses, including pushbuttons, relays, and similar devices, shall be provided with enclosures, and the
enclosure in each case, together with the enclosed apparatus, shall be identified as a complete assembly
for use in Class I locations.
(B) Class I, Division 2. Switches, circuit breakers, motor controllers, and fuses in Class I, Division 2
locations shall comply with 501.115(B)(1) through (B)(4).
(1) Type Required. Circuit breakers, motor controllers, and switches intended to interrupt current in
the normal performance of the function for which they are installed shall be provided with enclosures
identified for Class I, Division 1 locations in accordance with 501.105(A), unless general-purpose
enclosures are provided and any of the following apply:
(1) The interruption of current occurs within a chamber hermetically sealed against the entrance
of gases and vapors.
(2) The current make-and-break contacts are oil-immersed and of the general-purpose type
having a 50-mm (2-in.) minimum immersion for power contacts and a 25-mm (1-in.) minimum
immersion for control contacts.
(3) The interruption of current occurs within a factory-sealed explosion-proof chamber.
(4) The device is a solid state, switching control without contacts, where the surface temperature
does not exceed 80 percent of the ignition temperature in degrees Celsius of the gas or vapor
involved.
(2) Isolating Switches. Fused or un-fused disconnect and isolating switches for transformers or
capacitor banks that are not intended to interrupt current in the normal performance of the function for
which they are installed shall be permitted to be installed in general-purpose enclosures.
(3) Fuses. For the protection of motors, appliances, and lamps, other than as provided in
501.115(B)(4), standard plug or cartridge fuses shall be permitted, provided they are placed within
enclosures identified for the location; or fuses shall be permitted if they are within general-purpose
enclosures, and if they are of a type in which the operating element is immersed in oil or other
approved liquid, or the operating element is enclosed within a chamber hermetically sealed against
the entrance of gases and vapors, or the fuse is a non-indicating, filled, current-limiting type.
(4) Fuses Internal to Luminaires. Listed cartridge fuses shall be permitted as supplementary
protection within luminaires.
The standard open style fuse blocks without indication are acceptable. For touch safe protection the
SAMI series fuse covers can be used without the indicator option. The finger safe fuse holders such as
CH series or JT Series can be uses in Class 1 Div 2, as long as they are applied without the indicator
option.
Kindly,
Application Engineering Team