STTB Conduit Hubs

Allied Tube & Conduit PVC coated STTB conduit hubs are used to terminate conduit runs through the wall of a sheet metal electrical enclosure. They are available with or without grounding lug. STTB style hubs are ‘Through-Bulkhead’ fittings used to pass conduit runs through firewalls or bulkheads up to 1/8” thick.


  • Exterior PVC coating thickness is a minimum 0.040″
  • Interior Urethane coating thickness is a minimum 0.002″
  • STG and STTB available in 12 trade sizes from 1/2″ through 6″
  • Sealing sleeves on conduit side of hub
  • Molded PVC gasket seals flush with enclosure wall
  • Neoprene O-ring gasket provides additional seal
  • The length of the sleeve extension(s) shall be at least equivalent to the nominal conduit size for sizes 1/2″- 2″
  • For sizes 2-1/2″- 6″, the length of the sleeve extension(s) shall be at least 2″


  • UL 514B
  • NEC/CEC:
    • Class I, Division 2,
    • Class II, Division 1 & 2 Class III, Division 1 & 2
    • Class I, Zone 1, AEx e II
    • Class I, Zone 1, Ex e II
  • All Screw-tight Hubs are listed for NEMA type enclosures 2, 3, 3R, 4, 4x, 11 and 12
Item NumberTrade Size (in)ABCMax Wall ThicknessWeight Per 100 (lbs)
PV1200STTB41 1/42.943.255.880.25100
PV1500STTB51 1/23.193.506.380.25120
PV2500STTB72 1/24.224.758.440.25250
PV3500STTB93 1/24.385.508.760.25420
PA0500STTBA11/21.842.003.680.19Contact Factory
PA0700STTBA23/ Factory
PA1000STTBA312.662.505.320.25Contact Factory
PA1200STTBA41 1/42.943.255.880.25Contact Factory
PA1500STTBA51 1/23.193.506.380.25Contact Factory
PA2000STTBA623.754.257.500.25Contact Factory
PA2500STTBA72 1/24.224.758.440.25Contact Factory
PA3000STTBA834.315.258.620.25Contact Factory
PA3500STTBA93 1/24.385.508.760.25Contact Factory
PA4000STTBA1044.446.258.880.25Contact Factory