IL25F 25-Pin Female Inline Underwater Connector – SubConn Compatible Standard Circular Series

Product Overview

The HYSF SUBSEA IL25F 25-Pin Female Inline Underwater Connector is a high-density, wet-mateable subsea electrical connector designed for reliable multi-channel signal, control, and power connections in demanding marine environments.As part of the HYSF Standard Circular Connector Series, the IL25F features twenty-five gold-plated female electrical contacts, a durable molded neoprene rubber body, and an integrated underwater cable.Its high-density contact configuration enables multiple electrical circuits to be connected through a single underwater mating interface, making it particularly suitable for complex subsea instrumentation and marine electronic equipment.The connector belongs to a series designed for underwater operation at depths of up to 6,000 meters (60 MPa), subject to the qualification of the complete connector and cable assembly.The Standard Circular series has a rated operating voltage of 550V AC/DC. The 25-pin configuration has a nominal current rating of 5A per contact, with selected higher-current configurations potentially supporting up to 10A according to the approved contact arrangement.The standard IL25F is supplied with approximately 1 meter of underwater cable, while customized cable lengths, conductor configurations, and complete subsea cable assemblies can be specified for different engineering requirements.The IL25F is designed for mating compatibility with corresponding SubConn and SEACON Standard Circular underwater connectors.Its primary matching bulkhead connector is the BH25M 25-Pin Male Bulkhead Underwater Connector.Typical applications include remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs), sonar systems, hydrophone arrays, oceanographic instrumentation, offshore monitoring equipment, underwater sensor networks, and deep-sea research platforms.

Key Features and Benefits

1. High-Density 25-Pin Female Electrical Interface

The IL25F incorporates twenty-five electrical contact positions within a single Standard Circular connector interface.This configuration provides a practical solution for underwater equipment requiring numerous independent electrical channels.Potential applications include:

• Multiple underwater sensor connections
• Marine instrumentation circuits
• Electrical control signals
• Low-power distribution
• Underwater acoustic measurement channels
• Subsea monitoring systems
• Auxiliary equipment connections
• Multi-channel data acquisition
• Custom underwater wiring harnesses

Using a single 25-pin underwater connector can reduce the number of separate mating interfaces required in complex electrical systems.This may simplify cable routing, equipment installation, and maintenance.The actual circuit assignments depend on the electrical requirements of the connected equipment and the approved wiring configuration.

2. Nominal 5A per Contact Electrical Rating

The IL25F belongs to the HYSF Standard Circular 12/16/25 Pin Connector Series.Unlike the Standard 12-pin and 16-pin configurations, which have a catalog current rating of 10A per contact, the 25-pin configuration has a nominal rating of 5A per contact.The manufacturer’s catalog also identifies selected higher-current contact configurations reaching 10A.These higher-current ratings should not automatically be applied to all twenty-five contact positions.The permissible current depends on:

• Contact dimensions and configuration
• Cable conductor cross-sectional area
• Number of simultaneously loaded contacts
• Electrical termination design
• Operating temperature
• Cable length and voltage drop
• Complete assembly qualification

For applications requiring currents above 5A on particular contacts, the exact contact-specific ratings must be verified against the approved product drawing.

3. 550V AC/DC Rated Voltage

The HYSF Standard Circular 25-pin connector family is designed for electrical applications requiring a rated voltage of up to 550V AC/DC.This provides flexibility for appropriately designed subsea electrical systems.The IL25F can accommodate multiple circuits within one connector, provided the voltage and current ratings of the complete assembly are respected.Cable insulation, conductor separation, termination quality, and connected equipment specifications must also be considered.The allowable system voltage must not exceed the rating of the lowest-rated component.

4. SubConn and SEACON Compatible Standard Circular Design

The IL25F features a Standard Circular mating interface designed for compatibility with corresponding SubConn and SEACON connector configurations.This makes the connector suitable for consideration in compatible replacement applications and newly developed underwater equipment.Typical integration scenarios include:

• Replacement underwater cable assemblies
• ROV electrical system upgrades
• Marine instrument maintenance
• OEM subsea equipment development
• Offshore monitoring installations
• Custom underwater interconnection systems

Before connecting the IL25F to a connector manufactured by another company, verify the exact series, contact count, contact arrangement, mating geometry, and retention mechanism.Matching pin count alone does not guarantee compatibility.

5. Deep-Sea Capability up to 6,000 Meters

The HYSF Standard Circular connector series is designed for subsea environments involving high hydrostatic pressure.The series supports a design depth capability of up to 6,000 meters, approximately equivalent to 60 MPa.This makes the IL25F suitable for consideration in applications such as:

• Deep-sea scientific research
• Offshore underwater monitoring
• Seabed instrumentation
• Underwater robotic operations
• Marine environmental measurement
• Deep-water sensor systems

The molded body helps protect the electrical contact termination from external seawater exposure.Actual operating depth depends on the complete connector assembly, including the mating connector, cable construction, molded termination, and applicable pressure qualification.For critical underwater deployments, the complete assembly should be verified for the intended operating conditions.

6. Wet-Mateable Underwater Connection

The IL25F belongs to HYSF SUBSEA’s wet-mateable Standard Circular connector family.The interface is designed to support underwater mating and unmating under the applicable operating procedures.This capability can be valuable for modular underwater equipment and removable marine instruments.Typical applications include:

• ROV sensor replacement
• Underwater equipment servicing
• Modular subsea payloads
• Scientific instrument maintenance
• Detachable underwater cable assemblies

Important: Wet-mateable does not automatically mean live-mateable.Electrical power should be isolated before mating or unmating unless the complete connector system has been specifically qualified for energized operation.

7. Molded Neoprene Rubber Construction

The standard IL25F features a molded neoprene rubber connector body.Neoprene rubber provides flexibility and mechanical resilience for underwater electrical connector applications.The molded structure integrates the electrical contact assembly with the attached subsea cable.Its principal advantages include:

• Watertight molded construction
• Mechanical protection of cable terminations
• Suitability for marine environments
• Integrated cable entry
• Flexible installation
• Durable underwater connector construction

Proper cable routing and strain relief remain important.Excessive pulling, twisting, and sharp bending near the molded connector body should be avoided.

8. Gold-Plated Female Electrical Contacts

The IL25F incorporates twenty-five gold-plated female electrical contacts.Gold plating provides a conductive contact surface and helps reduce oxidation.Reliable electrical contact performance is especially important in subsea instrumentation systems requiring stable signal transmission and electrical continuity.The female mating interface is designed to engage with corresponding male connector contacts.Before mating, users should inspect the connector face for sand, sediment, salt deposits, and mechanical damage.Correct handling and regular inspection help maintain connector reliability.

9. Standard 1-Meter Cable with Customization Options

The standard IL25F is normally supplied with approximately 1 meter of underwater cable.This configuration provides a practical cable-mounted interface for subsea equipment.HYSF SUBSEA supports customized underwater cable assemblies for specific engineering applications.Customization options may include:

• Alternative cable lengths
• Different conductor sizes
• Shielded cable constructions
• Twisted-pair arrangements
• Customized pin assignments
• Special cable outer diameters
• Alternative cable jacket materials
• Open-ended wire terminations
• Connector-to-connector assemblies
• OEM underwater electrical harnesses

The chosen cable configuration should be evaluated against the required current, voltage, signal performance, operating depth, and mechanical loading.

IL25F Technical Specifications

Parameter	Specification
Brand	HYSF SUBSEA
Model Number	IL25F
Product Series	Standard Circular
Connector Type	Female Inline Underwater Connector
Number of Contacts	25
Contact Gender	Female
Contact Finish	Gold-Plated
Connector Body	Molded Neoprene Rubber
Rated Voltage	550V AC/DC
Nominal Rated Current	5A per Contact
Selected Higher-Current Configurations	Up to 10A, Subject to Approved Contact Arrangement
Design Depth Capability	Up to 6,000 Meters
Pressure Capability	Up to 60 MPa
Mating Type	Wet-Mateable
Standard Cable Length	1 Meter
Custom Cable Lengths	Available
Primary Mating Bulkhead	BH25M
Corresponding Male Inline Connector	IL25M
Protective Dummy Plug for IL25F	DC25M
Protective Dummy Plug for BH25M	DC25F
Compatibility	Corresponding SubConn and SEACON Standard Circular Interfaces
Warranty	12 Months

Technical Note: Current ratings above the nominal 5A per contact require confirmation of the applicable contact arrangement. Electrical and environmental performance must be evaluated for the complete connector and cable assembly.

25-Pin Wiring Configuration and Cable Identification

The HYSF Standard Circular 25-pin connector family provides a high-density conductor arrangement suitable for multi-channel electrical applications.Depending on the cable construction, the IL25F assembly may incorporate individual conductors, paired conductors, or shielded wiring configurations.Twisted-pair arrangements can be useful for certain instrumentation and communication circuits.However, the presence of twisted pairs does not automatically guarantee compatibility with Ethernet or any specific high-speed communication protocol.Signal performance depends on the complete cable design, including:

• Conductor pairing
• Characteristic impedance
• Shielding arrangement
• Cable capacitance
• Termination quality
• Signal frequency
• Cable length
• Grounding requirements

Pin-to-Wire Identification

The twenty-five contact positions should be identified using the approved IL25F wiring diagram.Wire colors and conductor identification may vary according to the selected cable construction.Before integrating an IL25F assembly into underwater equipment:

1. Confirm the contact numbering and connector viewing direction.
2. Verify the conductor identification corresponding to each pin.
3. Review the approved pin-to-wire assignment.
4. Perform electrical continuity testing.
5. Confirm that signal, power, and return conductors are connected correctly.

The final wiring configuration should be based on the approved production drawing.

Compatible Connectors and Accessories

BH25M – 25-Pin Male Bulkhead Underwater Connector

The BH25M is the primary male bulkhead mating connector for the IL25F.It is designed for installation through an underwater equipment enclosure, pressure housing, or marine instrumentation panel.The corresponding Standard Circular 12/16/25 Pin bulkhead family specifies:

• Mounting Thread: 3/4-16 UNF-2A
• Nominal Thread Length: 25 mm
• Base Mounting Radius: 32.4 mm
• Mounting Surface Roughness: Ra 1.6

These dimensions apply to the corresponding bulkhead mounting configuration, not to the IL25F inline cable connector.Before machining a pressure housing, verify the final BH25M installation drawing.Normal electrical connection:IL25F Female Inline Connector + BH25M Male Bulkhead Connector

IL25M – 25-Pin Male Inline Underwater Connector

The IL25M is the corresponding male inline connector within the Standard Circular 25-pin family.It features twenty-five male electrical contacts and an integrated underwater cable.A compatible IL25F and IL25M arrangement may be used for suitable cable-to-cable connections when the mating interface and retention system are correctly specified.Such arrangements may be useful for modular subsea electrical systems and underwater cable extensions.

DC25M – 25-Pin Male Dummy Plug

The DC25M is the corresponding male protective dummy plug for compatible female Standard Circular connector interfaces.It can help protect the IL25F female mating interface when the operational connection is disconnected, provided the mating and retention configuration is appropriate.The DC25M also serves as the corresponding protective accessory for the BH25F female bulkhead connector.A dummy plug does not provide functional electrical transmission.

DC25F – 25-Pin Female Dummy Plug

The DC25F is the corresponding female protective dummy plug for compatible male Standard Circular interfaces.It can help protect the exposed BH25M male bulkhead when the IL25F cable assembly is disconnected.The pressure capability of a complete dummy-plugged arrangement should be verified for the intended subsea deployment conditions.

IL25F vs. IL25M

The IL25F and IL25M belong to the same Standard Circular 25-pin connector family.Their primary difference is the electrical contact gender.

Feature	IL25F	IL25M
Connector Type	Female Inline	Male Inline
Number of Contacts	25	25
Contact Gender	Female	Male
Nominal Current Rating	5A per Contact	5A per Contact
Rated Voltage	550V AC/DC	550V AC/DC
Standard Cable Length	1 Meter	1 Meter
Primary Mating Bulkhead	BH25M	BH25F
Protective Dummy Plug	DC25M	DC25F

Both models support appropriately configured underwater cable assemblies.

Typical Applications of IL25F Underwater Connectors

1. Remotely Operated Vehicles (ROVs)

ROVs frequently use multiple sensors, control circuits, and auxiliary electronic systems.The IL25F provides a high-density electrical interface that can consolidate several circuits within one underwater cable connection.It can be integrated into suitable ROV sensor, monitoring, and instrumentation cable assemblies.

2. Autonomous Underwater Vehicles (AUVs)

AUV systems often require detachable connections between internal electronic systems and external scientific instruments.The IL25F provides a Standard Circular cable interface suitable for appropriately designed AUV electrical connections.Its twenty-five-contact configuration supports flexible allocation of power, control, and measurement circuits.

3. Sonar and Hydrophone Arrays

Sonar systems and hydrophone arrays may require multiple low-level signal connections.The IL25F can provide a multi-contact interface for underwater acoustic instrumentation.For sensitive signals, appropriate shielding, grounding, conductor pairing, and noise-control measures should be considered.

4. Oceanographic Research Instruments

Marine scientific equipment often requires numerous electrical connections for sensor excitation, measurement, control, and monitoring.The IL25F can be incorporated into suitable:

• Oceanographic data acquisition systems
• Marine environmental monitoring platforms
• Underwater sensor networks
• Scientific instrumentation packages
• Seabed observation equipment
• Deep-sea measurement systems

5. Underwater Cameras and Imaging Equipment

Underwater imaging systems may require separate conductors for power, control, auxiliary sensors, and communication circuits.The IL25F offers a high-density underwater electrical interface for appropriate camera and imaging equipment.High-speed data transmission capability must be verified using the complete cable and electrical system design.

6. Offshore Monitoring Equipment

Offshore monitoring systems may require multiple electrical channels under demanding marine conditions.The IL25F provides a detachable subsea cable interface for appropriately designed instrumentation and monitoring equipment.

7. Marine Research and Testing Equipment

Research laboratories and underwater equipment manufacturers often develop specialized instruments with customized wiring requirements.The IL25F provides a configurable high-density connector platform for suitable prototype, research, and testing applications.

Installation and Handling Guidelines

Step 1: Confirm the Mating Connector

Verify the selected mating interface is a compatible Standard Circular 25-pin male configuration.The primary matching bulkhead is BH25M.

Step 2: Inspect the Connector

Check the molded body, female contact interface, cable jacket, and termination area for visible damage.

Step 3: Clean the Mating Surface

Ensure the connector interface is free from sand, sediment, salt deposits, and foreign particles.

Step 4: Isolate Electrical Power

Disconnect electrical power before mating or unmating unless the assembly has been specifically qualified for energized operation.

Step 5: Align the Connector

Align the IL25F correctly with the corresponding male connector.Avoid excessive force or incorrect engagement.

Step 6: Complete the Mating Operation

Follow the approved mating procedure and secure the required locking or retention components.

Step 7: Protect the Cable

Provide appropriate strain relief and avoid excessive bending, pulling, or twisting near the molded cable termination.

Step 8: Verify Electrical Connections

Check the approved pin assignments and perform continuity and insulation verification before operation.For pressure-critical applications, confirm that the complete assembly meets the required subsea operating conditions.

Quality Control and Testing

HYSF SUBSEA manufactures underwater electrical connectors and customized subsea cable assemblies for demanding marine applications.Depending on the product configuration and project requirements, quality-control procedures may include:

• Hydrostatic pressure testing
• Electrical continuity testing
• Insulation resistance measurement
• Dielectric withstand testing
• Contact inspection
• Dimensional verification
• Cable termination inspection
• Wiring identification verification
• Mechanical integrity evaluation

Acceptance criteria should be defined according to the approved product configuration and operating requirements.

Frequently Asked Questions

Q1: What is the IL25F underwater connector?

The IL25F is a 25-pin female inline underwater electrical connector belonging to the HYSF Standard Circular Series.

Q2: Which bulkhead connector mates with IL25F?

The primary matching bulkhead connector is BH25M, a 25-pin male underwater bulkhead connector.

Q3: Is IL25F compatible with SubConn?

The IL25F is designed for mating compatibility with corresponding SubConn Standard Circular 25-pin interfaces.Exact compatibility should be verified using the connector drawings.

Q4: What is the rated current?

The nominal current rating is 5A per contact.Selected higher-current contact configurations may support up to 10A, subject to approved contact-specific ratings.

Q5: What is the rated voltage?

The Standard Circular series is rated for 550V AC/DC.

Q6: What is the maximum operating depth?

The series has a design depth capability of up to 6,000 meters (60 MPa), subject to qualification of the complete connector and cable assembly.

Q7: Is IL25F wet-mateable?

Yes. The IL25F belongs to the wet-mateable Standard Circular connector family.Electrical power should be isolated before mating or unmating unless energized operation has been specifically qualified.

Q8: What is the standard cable length?

The standard IL25F normally includes approximately 1 meter of underwater cable.

Q9: Can the cable length be customized?

Yes. Customized lengths, conductor configurations, and cable termination arrangements are available.

Q10: What is the difference between IL25F and IL25M?

IL25F has twenty-five female contacts, while IL25M has twenty-five male contacts.Both belong to the Standard Circular 25-pin family.

Q11: Does IL25F have a panel mounting thread?

No. The IL25F is a cable-mounted inline connector.The corresponding BH25M bulkhead uses a Standard 12/16/25-pin mounting arrangement with a 3/4-16 UNF-2A thread.

Q12: Which dummy plug protects IL25F?

The corresponding male protective accessory is DC25M, subject to the appropriate mating and retention configuration.

Q13: Which dummy plug protects BH25M?

The corresponding protective accessory is DC25F, a 25-pin female dummy plug.

Q14: Can IL25F transmit power and signals simultaneously?

The twenty-five contacts can be allocated to suitable power, control, and signal circuits within the approved electrical ratings.The system must be evaluated for current loading, conductor sizing, shielding, and interference.

Q15: Can IL25F support Ethernet communication?

Contact count alone does not establish Ethernet compatibility.The complete cable assembly must satisfy the required impedance, conductor pairing, shielding, and signal performance specifications.

Q16: Is IL25F suitable for custom subsea cable assemblies?

Yes. The IL25F can be incorporated into customized cable assemblies with different lengths, wiring assignments, conductor constructions, and termination configurations.

Why Choose HYSF SUBSEA IL25F?

The HYSF SUBSEA IL25F 25-Pin Female Inline Underwater Connector provides a durable, high-density electrical interface for demanding marine and subsea environments.Its principal advantages include:

• Twenty-five female electrical contacts
• SubConn-compatible Standard Circular mating interface
• Wet-mateable underwater connector design
• Nominal 5A per contact rating
• Higher-current contact options subject to verification
• 550V AC/DC rated voltage
• Design depth capability up to 6,000 meters
• Molded neoprene rubber connector body
• Gold-plated electrical contacts
• Standard 1-meter underwater cable
• Compatible BH25M male bulkhead connector
• Corresponding DC25M protective dummy plug
• Customized cable lengths and wiring configurations
• OEM underwater cable assembly options
• 12-month product warranty

For underwater robotic systems, sonar equipment, oceanographic instruments, offshore monitoring applications, and marine research platforms, the IL25F provides a practical solution for consolidating multiple electrical circuits into one underwater connection.Its high contact density, molded watertight construction, and compatibility with established Standard Circular interfaces make it suitable for complex subsea electrical integration projects.