The additional approved seal or barrier and the
interconnecting enclosure shall meet the temperature
and pressure conditions to which they will be subjected
upon failure of the primary seal, unless other approved
means are provided to accomplish the purpose in the
preceding paragraph.
Drains, vents, or other devices shall be provided so that primary seal leakage is obvious.
FPN: See also the fine print notes to 505.16.
Process-connected equipment that is listed and marked "Dual Seal" shall not require additional process sealing when used within the manufacturer's ratings.
FPN: For construction and testing requirements for dual seal process, connected equipment, refer to ANSI/ISA-12.27.01-2003, Requirements for Process Sealing Between Electrical Systems and Potentially Flammable or Combustible Process Fluids.
505.17 Flexible Cords, Class I, Zones 1 and 2. A flexible cord shall be permitted for connection between portable lighting equipment or other portable utilization equipment and the fixed portion of their supply circuit. Flexible cord shall also be permitted for that portion of the circuit where the fixed wiring methods of 505.15(B) cannot provide the necessary degree of movement for fixed and mobile electrical utilization equipment, in an industrial establishment where conditions of maintenance and engineering supervision ensure that only qualified persons install and service the installation, and the flexible cord is protected by location or by a suitable guard from damage. The length of the flexible cord shall be
continuous. Where flexible cords are used, the cords shall comply with the following:
(1) Be of a type listed for extra-hard usage
(2) Contain, in addition to the conductors of the circuit, an equipment grounding conductor complying with
400.23
(3) Be connected to terminals or to supply conductors in an approved manner
(4) Be supported by clamps or by other suitable means in such a manner that there will be no tension on the terminal connections
(5) Be provided with listed seals where the flexible cord enters boxes, fittings, or enclosures that are required to be explosionproof or flameproof
Exception to (5): As provided in 505.16.
(6) Cord entering an increased safety "e" enclosure shall be terminated with a listed increased safety "e" cordconnector.
FPN: See 400.7 for permitted uses of flexible cords. Electric submersible pumps with means for removal
without entering the wet-pit shall be considered
portable utilization equipment. The extension of the
flexible cord within a suitable raceway between the
wet-pit and the power source shall be permitted.
Electric mixers intended for travel into and out of open-type mixing tanks or vats shall be considered portable utilization equipment.
FPN: See 505.18 for flexible cords exposed to liquids hav- ing a deleterious effect on the conductor insulation.
505.18 Conductors and Conductor Insulation.
(A) Conductors. For type of protection "e," field wiring conductors shall be copper. Every conductor (including spares) that enters Type "e" equipment shall be terminated at a Type "e" terminal.
(B) Conductor Insulation. Where condensed vapors or liquids may collect on, or come in contact with, the insulation on conductors, such insulation shall be of a type identified for use under such conditions, or the insulation shall be protected by a