According to the NEC (National Electrical Code), the height requirements for explosionproof seals (EYS) in Class 1, Division 2 locations are not as strict as in Division 1. However, the NEC doesn't directly specify an 18" rule for EYS placement in Division 2.Here's a breakdown of what the NEC addresses and what factors influence EYS placement in Class I, Div 2 areas: General Requirements



NEC 501.15(B)(1)

Requires that where necessary to prevent the passage of gases or vapors. This suggests the need for seals is determined by the specific environment and equipment design.

NEC 501.15(B)(2)

Requires a seal within 18 inches of enclosures required to be explosion proof.

Division 2 Specifics

The specific circumstances of the location are critical in determining if and where seals are needed. Consider these factors:

Source of Hazard

Understanding the potential source of flammable gases or vapors is crucial. If the source is near the floor, that influences the need for a seal closer to the floor.

Equipment Design

The equipment manufacturer's instructions and documentation should be followed. Some equipment may already have integral seals.

Conduit Runs

Horizontal or vertical conduit runs influence vapor migration.

No Universal 18-Inch Rule

The NEC does not mandate that all seals in Class I, Division 2 locations be within 18 inches of the floor or above 18 inches.

In summary

The placement of EYS in a Class I, Division 2 location is dictated by whether they are necessary to prevent the passage of gases or vapors. If a seal is required, then it must be placed within 18" of the enclosure. A qualified electrical inspector should always be consulted to ensure compliance with the NEC and any applicable local codes.

Disclaimer: I am an AI Chatbot and not a qualified electrician. For definitive answers and code compliance, consult a licensed electrical professional and refer directly to the latest edition of the National Electrical Code. Flag for review