MCIL8M-CAT Micro In-Line Subsea Connector | 8-Pin Male CAT6 Ethernet | 1400 Bar

The MCIL8M-CAT is an 8-contact Micro Circular In-Line Male subsea connector pre-wired for CAT6 Ethernet, engineered for direct cable-to-cable connections in compact underwater systems. Rated to 300 V / 5 A per contact with a qualified hydrostatic pressure of 1,400 Bar (20,300 psi) when mated, it delivers high-speed data and mixed power-signal capability across AUV tether interfaces, compact instrument cable harnesses, and subsea sensor networks. Gold-plated contacts and chloroprene rubber construction provide 500+ wet mating cycles with insulation resistance consistently above 200 MΩ.

8 Contacts | 300 V DC/AC | 5 A/contact | 1,400 Bar Mated | 500+ Wet Matings | CAT6 Ethernet Ready

Key Design Features

• Micro Circular In-Line Male — direct cable-to-cable termination with compact footprint, no panel mount required
• 8-contact CAT6 configuration — 300 V / 5 A per contact, four twisted-pair layout supporting 1 Gbps Ethernet over subsea cable runs
• 1,400 Bar mated pressure — qualified to 1,400 Bar / 20,300 psi hydrostatic; standard PEEK variant rated 300 Bar / 4,350 psi
• 800 Bar open-face pressure — unmated connector face withstands 800 Bar / 11,600 psi without flooding
• 500+ wet mating cycles — qualified for repeated in-situ connection and disconnection in full-salinity seawater
• Gold-plated copper alloy contacts — contact resistance < 10 mΩ, corrosion-immune across the full service life in ocean salinity
• Chloroprene rubber body — resists seawater, hydraulic oil, and biofouling; stable from −40 °C to +60 °C
• Multi-material bulkhead options — brass, 316L stainless steel, titanium, anodised aluminium, or PEEK for weight and corrosion optimisation
• SubConn® Micro Circular intermatable — identical mating geometry to MacArtney SubConn® standard; direct field substitution with 15–20% cost saving

Electrical & Mechanical Specifications

Typical Applications

• AUV tether interfaces — 8-circuit power and high-speed data connections at payload bay connectors in compact harness designs
• Micro-ROV umbilicals — cable mid-run distribution and splice points where compact form factor is critical
• Subsea instrument networks — cable-to-sensor power and CAT6 data connections for oceanographic CTD, ADCP, and sonar systems
• Underwater camera and lighting — cable extension joints for HD and 4K video transmission with mixed power circuits
• Cabled observatories — inter-instrument compact cable connections in long-term seabed installation arrays
• Subsea mooring systems — cable-to-instrument connections in space-limited mooring frames and profiling floats
• Oceanographic gliders — inter-module cable connections where minimum connector mass and diameter are essential
• Naval and defence systems — compact connector for sonar array harnesses and underwater vehicle payload interfaces
• Subsea cable repair — field splice joints for compact underwater cable systems requiring wet-mateable in-situ reconnection

Why Choose the MCIL8M-CAT Over Generic Compact Underwater Connectors

1. CAT6 Ethernet — 1 Gbps Subsea Data Without Signal Compromise

The MCIL8M-CAT is pre-wired in a four-twisted-pair configuration that faithfully preserves CAT6 differential signal integrity from topside to subsea instrument. Generic 8-pin connectors route contacts as individual conductors, destroying pair geometry and introducing cross-talk that caps usable bandwidth below 100 Mbps. The MCIL8M-CAT maintains pair twist rates through the connector body, delivering full 1 Gbps throughput across the full rated depth range.

2. 1,400 Bar Qualified — Exceeds Any Commercial Deployment Depth

Qualified to 1,400 Bar (20,300 psi) when mated — equivalent to approximately 14,000 metres depth, exceeding the deepest point in the ocean (Challenger Deep, ~11,000 m). At typical ROV operating depths of 300–6,000 m, this rating provides a pressure safety factor of 2.3× to 46×, ensuring seals never approach their failure envelope even during rapid descent pressure transients and thermal cycling.

3. 500+ Wet Mating Cycles — Designed for Field Operations

Qualified for more than 500 wet mate/demate cycles in seawater — sufficient for the full operational life of most ROV tooling skids, instrument service programmes, and observatory maintenance schedules. Tin or nickel-plated contacts in generic connectors corrode within 20–50 seawater mate cycles, causing contact resistance to rise above usable thresholds. Gold-plated contacts in the MCIL8M-CAT maintain resistance below 10 mΩ across the full 500+ cycle life.

4. SubConn® Intermatable — 15–20% Cost Saving, Zero Redesign

All mating dimensions, keyway geometry, and contact pin spacing of the MCIL8M-CAT conform to the MacArtney SubConn® Micro Circular standard. Existing SubConn® harnesses, bulkhead panels, and mating halves connect directly — no cable modification, re-termination, or redesign required. For operators managing mixed fleets or mid-life equipment upgrades, this intermateability typically delivers a 15–20% procurement cost reduction vs. OEM SubConn® pricing.

5. Multi-Material Body — Optimised for Every Mission Profile

Bulkhead body options — brass, 316L stainless steel, titanium, anodised aluminium, and PEEK — allow system designers to match connector material to hull or chassis material, preventing galvanic corrosion in mixed-metal assemblies. Titanium bodies are specified for carbon-fibre AUV hulls; PEEK bodies for electrically isolated feedthroughs in CFRP pressure housings; 316L stainless for long-term seabed deployment arrays.

SubConn® Compatibility & Drop-In Replacement Guide

The MCIL8M-CAT is engineered as a fully intermatable replacement for the MacArtney SubConn® MCIL8M inline connector range. All mating dimensions, keyway orientation, locking sleeve geometry, and contact pin pitch are identical to the SubConn® Micro Circular standard, enabling direct field substitution without cable modification, re-termination, or system redesign.

Cost advantage: RV POWER GROUP Micro Circular connectors typically represent a 15–20% cost reduction vs. OEM SubConn® pricing, with identical dimensional and electrical interchangeability and equivalent pressure qualification.

How to Select the Right MCIL8M Configuration

Complete 8-Contact Micro Circular Connector Family

Frequently Asked Questions — MCIL8M-CAT Subsea Connector

Q: What is the maximum depth rating for the MCIL8M-CAT connector?
A: The MCIL8M-CAT is qualified to 1,400 Bar (20,300 psi) when mated, equivalent to approximately 14,000 metres water depth — exceeding the deepest point in any ocean. The open-face (unmated) pressure rating is 800 Bar / 11,600 psi. A PEEK body variant provides a certified depth rating of 300 Bar / 4,350 psi (~3,000 m).

Q: Is the MCIL8M-CAT compatible with MacArtney SubConn® Micro Circular connectors?
A: Yes — 100% intermatable. All mating dimensions, keyway orientation, locking sleeve engagement geometry, and contact pin pitch are identical to the MacArtney SubConn® Micro Circular standard. Existing SubConn® harnesses and mating halves connect directly without any cable modification or re-termination. This typically delivers a 15–20% cost saving vs. OEM SubConn® pricing.

Q: How many times can the MCIL8M-CAT be connected and disconnected underwater?
A: The connector is qualified for more than 500 wet mating cycles in seawater. This is sufficient for the full operational service life of most ROV tooling skids, instrument service programmes, and cabled observatory maintenance schedules.

Q: What cable diameter is compatible with the MCIL8M-CAT inline connector?
A: The standard MCIL8M-CAT accommodates cables from 2.5 mm to 6.0 mm outer diameter. For larger cables up to 11 mm OD, contact RV POWER GROUP for custom cable entry moulding options.

Q: Can the MCIL8M-CAT transmit 1 Gbps Ethernet signals underwater?
A: Yes. The CAT6 pre-wired configuration routes all four twisted pairs through the 8 contacts in a layout that preserves differential pair geometry, enabling 1 Gbps Ethernet transmission across the full rated depth range. This is the standard connector for subsea cameras, ROV control systems, and Ethernet-based instrument nodes.

Q: What body materials are available for the MCIL8M-CAT?
A: The connector body is chloroprene rubber (standard). Bulkhead body options include brass, 316L stainless steel, titanium, anodised aluminium, and PEEK. Titanium is recommended for long-term deployments or carbon-fibre hull interfaces. PEEK provides electrical isolation and chemical resistance for demanding environments.

Q: What is the difference between MCIL8M and MCBH8M?
A: The MCIL8M is an inline (cable-mount) connector that terminates a free cable and mates with a counterpart connector mid-run — used for cable-to-cable connections along a tether or harness. The MCBH8M is a bulkhead (panel-mount) connector that mounts through an instrument housing wall or chassis panel, creating a watertight feedthrough. Most subsea systems mount MCBH8M on the instrument housing and MCIL8M on the tether cable end.

Q: What is the operating temperature range for the MCIL8M-CAT?
A: In water: −4 °C to +60 °C. In air (deck handling and storage): −40 °C to +60 °C. Storage temperature range is also −40 °C to +60 °C. The chloroprene rubber body maintains sealing integrity and flexibility across the full range without plasticiser migration.

Q: What is the contact resistance specification for the MCIL8M-CAT?
A: Contact resistance is less than 10 mΩ per contact (specified as < 0.01 Ω in the MacArtney SubConn® datasheet). Gold-plated contacts maintain this specification across 500+ wet mating cycles in seawater — unlike tin or nickel contacts that exhibit resistance drift after 20–50 seawater cycles due to chloride-induced oxidation.

Q: Does the MCIL8M-CAT require lubrication before mating?
A: Light application of dielectric grease to the O-ring and contact face is recommended before every mating cycle, particularly for in-air mating on deck. For underwater mating, the surrounding seawater provides adequate lubrication. After recovery, flush with fresh water and apply grease before dry storage to prevent O-ring compression set.

Installation, Mating & Maintenance Guidelines

Pre-Mating Inspection

• Inspect both connector faces before every mating cycle — remove debris, biofouling, and salt crystal deposits from contact faces and locking surfaces
• Check the chloroprene body and O-ring surfaces for cuts, compression set, or delamination — replace immediately if damage is found
• Verify all 8 contacts are fully seated and free of corrosion, bent pins, or foreign material before mating
• Apply a thin film of dielectric grease to the O-ring sealing surface before deck-side (in-air) mating operations

Mating Procedure

• Align the keying feature precisely before applying axial load — misalignment is the primary cause of contact damage in compact circular connectors
• Apply steady axial pressure until the locking sleeve fully engages with an audible/tactile click — never force a partially engaged connector
• For underwater mating: approach slowly to allow pressure equalisation across the contact face before final engagement
• Do not apply rotational torque during mating — the locking sleeve is a push-lock mechanism; rotation damages the sleeve and body

Post-Recovery Maintenance

• Flush connector faces with fresh water immediately after recovery — chloride deposits accelerate oxidation if allowed to dry on gold contacts
• Apply dielectric grease to contact faces and O-ring surfaces before extended storage in the unmated condition
• Inspect contacts and body integrity after every 50 mate/demate cycles or 12 months of service, whichever occurs first
• Replace O-rings after 200 wet mating cycles or if any visible deformation, cracking, or compression set is observed

For technical datasheets, pressure test certificates, or custom cable entry configurations, contact RV POWER GROUP at [email protected]. Volume pricing and OEM supply programmes are available for qualified system integrators and equipment manufacturers.

• Micro_Circular_Series_of_underwaterconn_com.pdf