UpCodes logo
Go To Full Code Chapter
Seals installed in Class I, Division 1 and Division 2 locations shall comply with 501.15(C)(1) through (C)(6).
Exception: Seals that are not required to be explosionproof by 501.15(B)(2) or 504.70 shall not be required to comply with 501.15(C).
(1) Fittings
Enclosures that contain connections or equipment shall be provided with an integral sealing means, or sealing fittings listed for the location shall be used. Sealing fittings shall be listed for use with one or more specific compounds and shall be accessible.
(2) Compound
The compound shall provide a seal to minimize the passage of gas and/or vapors through the sealing fitting and shall not be affected by the surrounding atmosphere or liquids. The melting point of the compound shall not be less than 93°C (200°F).
(3) Thickness of Compounds
The thickness of the sealing compound installed in completed seals, other than listed cable sealing fittings, shall not be less than the metric designator (trade size) of the sealing fitting expressed in the units of measurement employed; however, in no case shall the thickness of the compound be less than 16 mm (5/8 in.).
(4) Splices and Taps
Splices and taps shall not be made in fittings intended only for sealing with compound; nor shall other fittings in which splices or taps are made be filled with compound.
(5) Assemblies
An entire assembly shall be identified for the location where the equipment that may produce arcs, sparks, or high temperatures is located in a compartment that is separate from the compartment containing splices or taps, and an integral seal is provided where conductors pass from one compartment to the other. In Division 1 locations, seals shall be provided in conduit connecting to the compartment containing splices or taps where required by 501.15(A)(1)(2).
(6) Conductor or Optical Fiber Fill
The cross-sectional area of the conductors or optical fiber tubes (metallic or nonmetallic) permitted in a seal shall not exceed 25 percent of the cross-sectional area of a rigid metal conduit of the same trade size unless the seal is specifically identified for a higher percentage of fill.

Related Code Sections

(C) Special Occupancies, Class I, Divisions 1 and 2
Seals installed in Class I, Division 1 and Division 2 locations shall comply with 501.15(C)(1) through (C)(6). Exception: Seals ...
(C) Special Occupancies, Class I, Divisions 1 and 2
Seals installed in Class I, Division 1 and Division 2 locations shall comply with 501.15(C)(1) through (C)(6). Exception: Seals ...
501.30 Special Occupancies, Grounding and Bonding, Class I, Divisions 1 and 2
Regardless of the voltage of the electrical system, wiring and equipment in Class I, Division 1 and 2 locations shall be grounded as specified ...