Mike Dolt Enterprises
Mike Dolt Enterprises
User: qms006
Asked on: Wednesday, April 20, 2011 at 6:37 pm EDT
Answered on: Tuesday, May 14, 2024 at 4:27 am EDT
Question: Got a question about Class I Div 1; I need to install a handhole adjacent to a manufacturing facility. The client indicates that below grade in the area where the handhole is to be installed is Class I Div 1. I don't see any handholes specically rated for Class I Div1. Are handholes not rated and explosionproof seals required inside the handhole or is nothing required since I'm not going above ground at the handhole?
Class I, Division 1 (Class I, Div 1) Environment
Class I, Div 1 areas are locations where flammable gases, vapors, or liquids are present in sufficient quantities to produce explosive or ignitable mixtures.
Handholes in Class I, Div 1 Environments
Handholes themselves are not typically rated for Class I, Div 1 environments. Instead, it is the components installed within the handhole that require specific ratings.
Explosion-Proof Seals
Explosion-proof seals are required to maintain the integrity of the electrical system and prevent the passage of flame or explosion from within the handhole to the surrounding Class I, Div 1 area. These seals must meet the requirements of the NEC and be approved for use in Class I, Div 1 environments.
Other Considerations Conduit Seals
Conduits entering the handhole must be sealed using explosion-proof conduit seals.
Light Fixtures
Any light fixtures installed within the handhole must be explosion-proof.*
Ventilation
Adequate ventilation must be provided to prevent the accumulation of flammable gases or vapors.
Conclusion
While handholes themselves are not specifically rated for Class I, Div 1 environments, explosion-proof seals and other components installed within the handhole must be rated for use in such areas. This is essential to maintain the integrity of the electrical system and prevent the risk of explosion or fire. Flag for review