MCIL21F 21-Pin Female Inline Underwater Connector – SubConn Compatible | HYSF SUBSEA

MCIL21F 21-Pin Female Inline Underwater Connector for Deep-Sea Applications

The MCIL21F 21-pin female inline underwater connector from HYSF SUBSEA is a high-density, wet-mateable electrical connector designed for reliable power and signal connections in demanding subsea environments.Featuring 21 female electrical contacts, a durable neoprene rubber body, and a compact Micro Circular design, the MCIL21F provides a practical solution for underwater systems that require multiple electrical circuits within a single connector interface.The MCIL21F is particularly suitable for remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs), underwater sensor networks, oceanographic research equipment, subsea monitoring systems, and other advanced marine applications.As part of the HYSF SUBSEA Micro Circular connector family, the MCIL21F is designed for underwater operation at depths reaching approximately 6,000 meters, corresponding to a hydrostatic pressure of 60 MPa, when used as part of a correctly configured and qualified assembly.The connector is designed to mate with corresponding 21-pin male Micro Circular connectors, including the MCBH21M male bulkhead connector and MCIL21M male inline connector.With a standard cable length of 1 meter and support for customized cable assemblies, the MCIL21F offers flexibility for both standard subsea installations and OEM equipment development.

Key Features of the MCIL21F Underwater Connector

The MCIL21F combines high contact density with the protective features required for underwater electrical connections.Key features include:

• 21-pin female configuration: Provides 21 individual electrical contacts within one compact connector interface.
• Micro Circular design: Suitable for subsea equipment requiring high-density electrical connections.
• Wet-mateable construction: Designed for underwater mating and unmating when used according to the applicable handling requirements.
• Deep-sea pressure capability: Standard Micro Circular series designed for depths up to approximately 6,000 meters.
• Durable neoprene rubber body: Provides flexibility and environmental protection in marine conditions.
• Gold-plated electrical contacts: Supports reliable electrical connections and resistance to contact corrosion.
• SubConn-compatible interface: Designed for compatibility with corresponding SubConn-style Micro Circular connectors.
• Standard 1-meter cable: Provides a convenient starting configuration for subsea cable installations.
• Custom cable lengths available: Supports project-specific wiring and integration requirements.
• Multi-circuit connectivity: Suitable for sensor signals, equipment control, and appropriately rated electrical power circuits.
• OEM integration: Can be incorporated into custom subsea cable assemblies and underwater equipment designs.

These features make the MCIL21F a practical choice for engineers searching for a 21-pin female underwater cable connector for ROVs and deep-sea instruments.

MCIL21F Technical Specifications

Parameter	Specification
Brand	HYSF SUBSEA
Model Number	MCIL21F
Connector Series	Micro Circular
Connector Type	Female Inline Underwater Connector
Number of Contacts	21
Contact Gender	Female
Contact Finish	Gold-Plated
Standard Body Material	Neoprene Rubber
Rated Current	5 A per Contact
Voltage Rating	Up to 550 V AC/DC, subject to configuration
Maximum Series Pressure Rating	60 MPa
Approximate Depth Rating	6,000 m Seawater
Standard Cable Length	1 Meter
Mating Male Bulkhead Connector	MCBH21M
Mating Male Inline Connector	MCIL21M
Protective Dummy Connector	MCDC21M
Connector Technology	Wet-Mateable Micro Circular
Compatibility	Corresponding SubConn and SEACON Micro Circular Interfaces
Custom Cable Assemblies	Available
Warranty	12 Months

Important: Electrical ratings, conductor sizes, cable diameter, and pressure performance should be verified against the approved product drawing and complete cable assembly configuration. Continuous current capacity may depend on conductor size, contact loading, and operating conditions.

High-Density 21-Pin Electrical Connection

Modern subsea equipment frequently requires multiple power, signal, and control circuits.For example, an underwater research vehicle may use several electrical channels for environmental sensors, navigation instruments, camera controls, monitoring systems, and auxiliary equipment.Using individual connectors for every electrical circuit can increase equipment complexity, installation space, and the number of connection points that require maintenance.The MCIL21F 21-contact underwater electrical connector provides a compact alternative by combining 21 separate contacts within a single Micro Circular interface.This design can simplify cable management and help reduce the number of external connectors required by a system.Possible electrical applications include:

• Underwater sensor signal transmission
• Instrument control circuits
• Low-power electronic equipment
• Monitoring and diagnostic signals
• Auxiliary power connections
• Subsea data acquisition systems
• Multiple independent signal channels
• Marine automation equipment

The precise circuit arrangement depends on the customer’s electrical design.When power and signal circuits are combined within the same connector, engineers should consider current requirements, cable construction, shielding, conductor size, and electromagnetic interference.The number of contacts does not automatically determine compatibility with Ethernet or other high-speed communication standards. Such applications require evaluation of the complete cable assembly and electrical performance.

Wet-Mateable Design for Underwater Operations

The MCIL21F belongs to the HYSF SUBSEA wet-mateable Micro Circular connector family.Wet-mateable connectors are designed to support connection and disconnection in underwater environments when the correct mating components and handling procedures are used.This capability is valuable for underwater equipment that requires periodic maintenance, replacement, or reconfiguration.Examples include:

• ROV equipment servicing
• AUV payload replacement
• Underwater instrument maintenance
• Sensor cable replacement
• Marine research equipment installation
• Subsea equipment inspection

The connector’s mating interface is designed to work with corresponding male Micro Circular connectors.During installation, operators should ensure that the connectors are correctly aligned and that their mating surfaces are free from damage and contamination.Unless a particular assembly has been specifically designed and approved for energized mating, electrical power should be switched off before connecting or disconnecting underwater connectors.

Durable Neoprene Rubber Construction

The standard MCIL21F features a molded neoprene rubber body designed for marine and subsea applications.Neoprene is commonly used in underwater connector construction because it provides flexibility and resistance to moisture.The molded connector body helps protect the electrical interface and cable termination from the surrounding environment.This construction is important for equipment exposed to:

• Seawater
• Hydrostatic pressure
• Mechanical handling
• Repeated deployment and recovery
• Underwater vibration
• Offshore environmental conditions

The MCIL21F also uses gold-plated electrical contacts.Gold plating helps maintain a stable contact interface and reduces the risk of corrosion-related electrical problems.For underwater equipment expected to operate over extended periods, proper connector handling and maintenance remain essential.

Deep-Sea Operation up to 6,000 Meters

The HYSF SUBSEA Micro Circular connector series is designed for demanding underwater environments.The standard series has a nominal pressure capability of 60 MPa, approximately equivalent to 6,000 meters of seawater.This makes the MCIL21F relevant to deep-sea research, underwater robotics, offshore inspection, and submerged monitoring applications.However, a connector’s pressure capability must be considered as part of the complete subsea electrical system.Performance depends on several factors:

1. Correct connector mating
2. Proper cable termination
3. Compatible sealing surfaces
4. Appropriate cable construction
5. Mechanical retention and locking
6. Installation conditions
7. Pressure qualification of the complete assembly

For equipment operating at significant water depths, the connector and cable assembly should be reviewed against the applicable engineering requirements.

Standard 1-Meter Cable and Custom Length Options

The standard MCIL21F configuration is supplied with approximately 1 meter of cable.This provides a convenient option for laboratory testing, prototype development, and subsea equipment integration.However, underwater cable requirements vary considerably between applications.A compact ROV may need a short cable to connect a sensor to a nearby pressure housing, while a larger underwater research system may require a longer assembly.HYSF SUBSEA supports customized cable configurations according to project requirements.Possible options include:

• Customized cable lengths
• Alternative cable outer diameters
• Project-specific conductor arrangements
• Customized wire identification
• Special pin assignments
• Male-to-female underwater cable assemblies
• Cable-to-bulkhead connection configurations
• OEM cable integration

For example, a customer may require an MCIL21F to MCIL21M underwater cable assembly with a specified cable length and wiring arrangement.Another project may require an MCIL21F connector with an open-ended cable for integration into a subsea control module.The conductor configuration and completed assembly should be confirmed through the approved technical drawing.

Compatible Mating Connectors

The MCIL21F is a female inline connector containing 21 female electrical contacts.It is designed to mate with corresponding male Micro Circular connectors.

MCBH21M – 21-Pin Male Bulkhead Connector

The MCBH21M is a male bulkhead connector designed for installation on underwater equipment housings.When an MCIL21F female cable connector is mated with an MCBH21M male bulkhead connector, the assembly provides a detachable electrical connection between the external cable and the equipment’s internal circuits.This configuration is commonly used for underwater sensor modules, ROV electronic housings, and marine research instruments.A typical connection arrangement is:MCIL21F Female Inline Cable → MCBH21M Male Bulkhead → Internal Equipment WiringThe corresponding MCBH21M bulkhead family uses a 5/8-18 UNF mounting-thread configuration. Exact mounting dimensions should be confirmed using its approved drawing.

MCIL21M – 21-Pin Male Inline Connector

The MCIL21M is the corresponding male inline underwater connector.It can be used with the MCIL21F to create detachable cable-to-cable connections.This is useful for:

• Underwater cable extensions
• Modular subsea equipment
• Detachable instrument cables
• ROV cable assemblies
• Marine research systems

A typical connection arrangement is:MCIL21F Female Inline Connector → MCIL21M Male Inline ConnectorThe wiring arrangement must be verified for the intended application.

Protective Dummy Connector: MCDC21M

When the MCIL21F is disconnected from its mating male connector, its female electrical interface should be protected.The corresponding protective accessory is the MCDC21M 21-pin male dummy connector.A suitable dummy connector helps protect the exposed mating interface from contamination and mechanical damage during storage, transportation, and maintenance.The MCDC21M is a protective accessory rather than an operational electrical connector.It is particularly useful for spare cables and equipment that undergoes frequent deployment and recovery.

SubConn and SEACON Compatible Underwater Connector

HYSF SUBSEA manufactures Micro Circular underwater connectors designed to match corresponding SubConn and SEACON-style interfaces.The MCIL21F is intended for applications requiring a SubConn-compatible 21-pin female inline connector.This provides an alternative option for subsea equipment manufacturers and maintenance teams working with compatible Micro Circular connector systems.However, exact compatibility should be checked before purchasing replacement components.Important factors include:

• Connector series
• Contact count
• Contact arrangement
• Mating gender
• Mechanical keying
• Locking mechanism
• Cable configuration
• Electrical requirements

The MCIL21F should not be confused with a Standard Circular connector or a dedicated Ethernet-series connector.

Applications of MCIL21F Underwater Connector

1. Remotely Operated Vehicles (ROVs)

ROVs rely on multiple electrical systems for sensors, monitoring equipment, control circuits, and auxiliary devices.The MCIL21F provides a high-density electrical interface suitable for combining numerous circuits within one subsea cable connection.

2. Autonomous Underwater Vehicles (AUVs)

AUVs often require compact electrical connectors for scientific instruments, navigation equipment, and modular payload systems.The MCIL21F supports equipment designs where multiple electrical channels must be connected within limited installation space.

3. Oceanographic Research Equipment

Marine research instruments may require several separate electrical circuits for environmental monitoring and data acquisition.A 21-pin underwater cable connector can help simplify the integration of these circuits.

4. Underwater Sensor Networks

Subsea sensor systems frequently include multiple measurement channels and monitoring devices.The MCIL21F can be used in suitable cable assemblies connecting these devices to underwater electronics.

5. Offshore Monitoring Systems

Offshore installations may require waterproof electrical connections for instrumentation, diagnostics, and control systems.The MCIL21F provides a compact solution for appropriately rated multi-circuit applications.

6. Sonar and Hydrophone Equipment

Marine acoustic systems may include multiple electrical signal channels and auxiliary circuits.The MCIL21F can be considered for such applications when the cable construction, shielding, noise performance, and pin assignments satisfy the system requirements.

Standard Cable Wire Color Identification

For reference, the HYSF SUBSEA Micro Circular 21-pin series uses the following standard cable identification sequence:

Pin Number	Wire Color
1	Red
2	Red/White
3	Black
4	Black/White
5	Yellow
6	Yellow/White
7	Blue
8	Blue/White
9	Orange
10	Orange/White
11	Brown
12	Brown/White
13	Purple
14	Purple/White
15	Green
16	Green/White
17	Pink
18	Pink/White
19	Light Blue
20	Light Blue/White
21	Grey

Note: This is the standard series reference. Custom cable assemblies may use different wire colors or conductor arrangements. Always follow the approved wiring drawing for the specific order.

Quality Control and Testing

Reliable electrical connections are essential for subsea equipment.HYSF SUBSEA applies quality-control procedures suitable for underwater connector production.Depending on the product configuration and project requirements, testing may include:

• Hydrostatic pressure testing
• Electrical continuity testing
• Insulation resistance testing
• Dielectric withstand testing
• Contact and mating inspection
• Visual inspection of molded components
• Cable assembly inspection
• Mechanical and environmental testing

For critical subsea applications, additional project-specific acceptance criteria may be established.

Frequently Asked Questions

What is the MCIL21F?

The MCIL21F is a 21-pin female Micro Circular underwater inline connector manufactured by HYSF SUBSEA. It is designed for multi-circuit electrical connections in marine and subsea environments.

Is the MCIL21F male or female?

The MCIL21F is a female connector with 21 female electrical contacts.

Which connector mates with the MCIL21F?

The MCIL21F can mate with corresponding 21-pin male Micro Circular connectors, including the MCBH21M male bulkhead connector and MCIL21M male inline connector.

What is the standard cable length?

The standard MCIL21F cable length is approximately 1 meter. Customized lengths are available according to project requirements.

What is the depth rating of MCIL21F?

The standard Micro Circular series is designed for pressures up to 60 MPa, corresponding to approximately 6,000 meters of seawater, subject to the approved connector and cable assembly configuration.

Is the MCIL21F compatible with SubConn connectors?

The MCIL21F is designed for corresponding SubConn-style Micro Circular interfaces. The exact mechanical and electrical configurations should be confirmed before cross-brand use.

What is the rated current?

The standard 21-pin Micro Circular series is rated at 5 A per contact. The permitted current in a complete cable assembly depends on conductor specifications and operating conditions.

Can the MCIL21F transmit both power and signals?

Yes. Different contacts may be assigned to suitable electrical power and signal circuits, provided the complete design meets the applicable electrical requirements.

Which dummy connector protects MCIL21F?

The appropriate protective accessory is the MCDC21M 21-pin male dummy connector.

Can the MCIL21F be customized?

Yes. HYSF SUBSEA supports customized cable lengths, wiring arrangements, and underwater cable assemblies for OEM subsea equipment.

Reliable 21-Pin Underwater Connectivity for Subsea Equipment

The HYSF SUBSEA MCIL21F 21-pin female inline underwater connector combines high-density electrical connectivity with a durable, wet-mateable Micro Circular design.Its 21-contact arrangement, gold-plated contacts, neoprene rubber construction, and deep-sea pressure capability make it suitable for demanding subsea applications.For engineers searching for a 21-pin female underwater cable connector, a SubConn-compatible Micro Circular inline connector, or a deep-sea waterproof electrical connector for ROVs and AUVs, the MCIL21F provides a flexible solution within the HYSF SUBSEA connector range.