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BIRNS NPT Series Penetrators


BIRNS NPT Penetrators

BIRNS penetrators safely and reliably transmit electrical power or signal through a pressure boundary, decrease the complexity of electrical systems and reduce dependence on operator skill. They are extremely rugged, require minimal maintenance, and are engineered for long-term deployment.

BIRNS provides the industry’s highest volume of cost-effective, in-house hydrostatic and helium pressure testing. Thus, BIRNS penetrators are the only ones in the industry that can be ordered with inclusive pricing and lead time for stringent ABS certification.


BIRNS has American Bureau of Shipping (ABS) Product Design Assessment (PDA) Certification for its tremendously popular lines of penetrators.  This certification process included rigorous testing and review by the national organization, and resulted in ABS pre-approving all design, drawing and test procedures for BIRNS electrical penetrators and cable assemblies for underwater vehicles, systems and hyperbaric facilities for use on a variety of ABS-class vessels.

BIRNS NPT (National Pipe Tapered) penetrators have standard tapered pipe threads and are widely used on diving bells, decompression chambers.  They can be configured for a wide range of demanding applications. They are constructed of AISI 316 stainless steel, passivated per  QQ-P-35 type VI.  They are rated for use up to 80°C (176°F) when fabricated with neoprene (polychloroprene) cable jackets, or up to 95°C (203°F) with optional CSPE cable jackets.

Available sizes:

P13N (.50” NPT up to 4 conductors)
P19N (.75” NPT up to 12 conductors)
P25N (1.0” NPT up to 16 conductors)

BIRNS NPT penetrators meet or exceed ABS and DNV requirements when fabricated with Low Smoke Zero Halogen (LSZH) cables inboard.  All BIRNS penetrators are individually serialized, certified and tested in accordance with BIRNS’ ABS-approved test procedure ETP-6510-101.


BIRNS can customize penetrators to specific requirements, including:

  • Cable length (inboard and outboard)
  • Conductor quantity and size
  • Straight or 90° cable molding
  • Cable jacket material
  • Test methods and witnessing

Specific Customizations:

  • Cable Length (inboard to 18m/60′; outboard to 3m/10′ or on special order to 4.5m/15′)
  • Cable Stock, including conductors quantity and size (See conductor color coding)
  • Wiring of TSP/STP (screened twisted pairs):
    • leave the shields not connected (“floating shields”)
    • “marry” all (or some) of the shields to one or more or more penetrator pins
    • terminate each shield to its own penetrator pin
    • terminate overall shield to Penetrator shell…or isolate it from the shell, as you prefer
  • Straight or 90° cable molding
  • Cable jacket material. We use BIRNS 52D-089 LSZH wire (tails/flying leads) inboard unless otherwise specified. For 52D-089 LSZH wire inboard, add the suffix “-LS” to the part number (e.g. P38100-24-RA-LS)

BIRNS Penetrators FAQ