• Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F
  • Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F
  • Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F
  • Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F
  • Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F
  • Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F
  • Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F
  • Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F
  • Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F
  • Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F
  • Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F
  • Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F

Underwater Connectors Micro Circular - 21 Contacts · Voltage rating 300 V DC/AC rms MCIL21F

MCIL21F 21-contact Micro Circular in-line wet-mate connector, female (sockets), 300 V DC/AC, 5 A per contact (max 40 A), 7,000 m depth, IP68, mates with MCBH21M / MCIL21M.
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MCIL21F Micro Circular In-Line Connector — Overview

The MCIL21F is a 21-contact Micro Circular in-line subsea connector, female (sockets) face, wet-mateable and rated to 5 A per contact (40 A per connector) at 7,000 m working depth. It terminates a free cable and mates mid-run, with no panel or chassis mount required.

21 Contacts 300 V AC/DC 5 A per Contact 7,000 m Depth 500+ Wet Matings IP68

Key Design Features

  • Wet-mateable: mate and demate in seawater; each contact carries its own moulded O-ring seal, so a single seal failure does not flood the connector.
  • SubConn Compatible: identical face geometry, contact pitch and 5/8-18 UNF-2A thread, so it retrofits existing SubConn panels and harnesses without re-machining.
  • Gold-plated contacts: sockets in brass UNS-C36000, pins in beryllium copper, holding contact resistance below 0.01 Ω across the full 500-cycle life.
  • 5 A per contact: rated current with a 40 A connector limit for the 21-contact shell.
  • Pressure qualified: 1,400 bar mated design depth, 800 bar open face, so the face survives handling and storage unmated.
  • Moulded cable: factory-moulded strain relief, so there is no crimp joint to fail at the cable entry.

Technical Specifications

ParameterSpecification
ModelMCIL21F
Contact count21 contacts
GenderFemale (sockets)
MountingIn-Line (cable-to-cable)
Rated voltage300 V DC/AC rms
Rated current5 A per contact (max. 40 A per connector)
Contact resistance< 0.01 Ω
Insulation resistance> 200 MΩ
Operating depth7,000 m (700 bar / 10,000 psi)
Design depth (mated)1,400 bar / 20,300 psi (approx. 14,000 m)
Open face qualified800 bar / 11,600 psi
PEEK body variant300 bar / 4,350 psi
Operating temperature (water)-4 °C to +60 °C (+25 to +140 °F)
Operating temperature (air)-40 °C to +60 °C (-40 to +140 °F)
Storage temperature-40 °C to +60 °C (-40 to +140 °F)
Wet mating cycles> 500
Ingress protectionIP68
Coupling5/8-18 UNF-2A threaded locking sleeve

Materials

ParameterSpecification
Connector bodyChloroprene rubber
ShellBrass / 316L stainless steel (nickel-plated)
ContactsFemale sockets: gold-plated brass UNS-C36000; male pins: gold-plated beryllium copper
O-ringsNitrile rubber
Locking sleevePOM or stainless steel
Snap ringsStainless steel AISI 302
Location pinStainless steel AISI 303

Cable & Termination

ParameterSpecification
Cable2 ft (60 cm) moulded cable as standard; 5 m and custom lengths on request
Conductor size20 AWG, 0.52 mm² synthetic rubber
Nominal cable OD14.70 mm
Wire colour code1 Grey, 2 Purple, 3 Blue, 4 Green, 5 Yellow, 6 Orange, 7 White/black, 8 White, 9 White/brown, 10 White/red, 11 White/orange, 12 White/yellow, 13 White/green, 14 White/blue, 15 White/purple, 16 White/grey, 17 White/brown/black, 18 White/red/black, 19 White/orange/black, 20 White/yellow/black, 21 White/green/black

Mating & Compatibility

ParameterSpecification
Mates withMCBH21M (bulkhead male) or MCIL21M (in-line male)
Dummy connectorMCDC21M
InterchangeabilitySubConn Compatible — MCBH / MCIL / MCOM series; also interchangeable with SeaCon and Burton micro circular equivalents

Typical Applications

AUV payload interfaces, multi-sensor oceanographic packages, compact tether breakouts, acoustic modem links.

Notes for Selection

Female half of the 21-contact pair: 300 V, 5 A per contact, 40 A limit, with sockets in gold-plated brass and pins in gold-plated beryllium copper on the mating half.

Custom configurations available Shell material (brass / 316L stainless steel / titanium / anodised aluminium / PEEK), thread and lead length, pin-out, cable length and hydrostatic test certificates can be specified to order. Send us your drawing or mating requirement for a quotation.