ESU 25 Percent Fill

25%* Fill. Vertical and Horizontal.
Explosionproof, Dust-Ignitionproof, Raintight.
Unilets® for Use with Threaded Rigid Metal Conduit and IMC.

  • NEC/CEC:
    – Class I, Division 1 and 2 Groups C, D
    – Class II, Division 1 and 2 Groups E, F, G
    – ​Class III


These sealing fittings minimizes the passage of gases and vapors and prevents the passage of flames from one portion of a conduit system to another. They prevent pressure piling the within conduit system and contain any explosion that occurs. The ESU Series provides a pouring spout that rotates 90° for sealing vertical or horizontal conduit.


ESU 25 Percent Fill Vertical and Horizontal Conduit Sealing Fittings Catalog Pages

Applications Features Catalog Numbers Related Products
  • For sealing vertical conduit
  • Prevent pressure piling within conduit system
  • Required in Class I, Division 1 and 2 locations:
  • Within 18" of enclosures containing apparatus that may cause arcs, sparks or high temperatures
  • Where 2" or larger conduit enters enclosure, fitting housing terminals, splices or taps
  • At the boundary where conduit leaves classified location
  • Where two or more enclosures are connected by 36" or less conduit (seal must be located within 18" of either enclosure). Required where cables (which exceed rate of gas or vapor transmission permitted for seals) are used in Class I, Division 2 locations
* Per NEC 501.15(C)(6) seals in Class I, Division 1 and 2 must be limited to conductor fill of 25% of cross sectional area of a rigid metal conduit of the same trade size unless approved for higher percentage fill. See 40% fill sealing fittings.​
ESU 25 Percent Fill Vertical and Horizontal Conduit Sealing Fittings