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The Allen-Bradley 1786-TNCJI4 is an isolated bulkhead connector used in ControlNet coaxial communication systems. It features a jack-to-jack TNC connection and is intended for installations where coaxial network cables must pass through grounded metal panels without creating a direct electrical connection between the cable shield and the mounting panel.
Unlike a conventional inline TNC coupling, the 1786-TNCJI4 incorporates an isolated bulkhead structure. This makes it particularly useful when ControlNet trunk cables enter or leave electrical cabinets, equipment enclosures, and industrial control panels.
For example, a production facility may have its ControlNet coaxial trunk routed between two control cabinets. When the cable passes through a grounded metal enclosure wall, the 1786-TNCJI4 provides a mounting interface that maintains shield isolation while allowing the coaxial connection to continue through the panel.
The connector has female TNC interfaces on both sides. Compatible male TNC cable connectors can be attached from either side, allowing the network connection to be assembled without permanently terminating the cable directly at the panel.
The 1786-TNCJI4 belongs to the ControlNet IP67 TNC media component family. Its environmental protection depends on proper mating with compatible sealed connectors and correct installation of the bulkhead assembly.
It is important to distinguish this component from the 1786-TNCJ4. Although both use jack-to-jack TNC connections, the TNCJ4 is a bullet-style inline connector, whereas the TNCJI4 is an isolated bulkhead connector intended for panel-mounted installations.
The 1786-TNCJI4 is a passive media component. It does not amplify communication signals, regenerate network data, or require an independent power supply. Its purpose is to maintain the coaxial signal path while providing electrical isolation at the panel interface.
| Parameter | Specification |
|---|---|
| Manufacturer | Allen-Bradley |
| Brand | Rockwell Automation |
| Model | 1786-TNCJI4 |
| Product Series | ControlNet |
| Product Type | ControlNet Media Connector |
| Component Type | Isolated Bulkhead Connector |
| Connection Configuration | Jack-to-Jack |
| Connector Type | TNC |
| Connector Arrangement | TNC-to-TNC |
| Media Type | RG-6 Coaxial |
| Network Compatibility | Allen-Bradley ControlNet |
| Environmental Protection | IP67 when fully mated |
| Operating Temperature | -20 to +80°C |
| Package Quantity | 4 pieces |
| Mounting Type | Panel Bulkhead |
| Application | Isolated Coaxial Connection Through Grounded Panels |
| Dimensions | 50 × 20 × 40 mm |
| Weight | 0.1 kg |
The 1786-TNCJI4 establishes a coaxial connection through a grounded panel while maintaining electrical isolation between the cable shield and the panel structure.
In a conventional coaxial connection, the outer conductor provides the shielding path and is electrically connected through the connector body. When a cable connection passes through a grounded metal cabinet wall, this arrangement can create an unwanted electrical connection between the cable shield and the enclosure.
The isolated bulkhead construction addresses this installation requirement by separating the connector’s electrical interface from the grounded mounting structure.
Both sides of the 1786-TNCJI4 accept compatible male TNC connectors. The center conductor maintains the signal path between the two cable sections, while the isolated bulkhead arrangement prevents the connector from directly bonding the cable shield to the grounded panel.
A typical connection arrangement is:
ControlNet RG-6 Cable → TNC Male Connector → 1786-TNCJI4 → TNC Male Connector → ControlNet Network Cable
The threaded TNC connections provide mechanical retention at both sides of the panel. When correctly assembled with compatible sealed components, the connection can also maintain the IP67 environmental protection requirement.
The connector does not perform signal amplification or network regeneration. Its role is limited to maintaining the coaxial connection and providing the required isolation at the panel interface.
This distinction matters in ControlNet installations where grounding and shielding arrangements must be carefully controlled. A conventional inline connector may maintain signal continuity but cannot automatically provide the same panel isolation function.
The 1786-TNCJI4 serves as an isolated media interface within the ControlNet coaxial network architecture. It allows TNC cable connections to pass through grounded enclosure walls while maintaining the intended electrical separation between the cable shield and the panel.
A typical installation may use the connector together with a ControlNet IP67 tap assembly. The tap connects to the bulkhead through the appropriate TNC plug-to-plug adapter, while the opposite side provides the connection to the coaxial cable routed through the enclosure.
A representative arrangement is:
ControlNet RG-6 Trunk → 1786-TNCJI4 → 1786-TNCLP4 → 1786-TCT2BD1 → ControlNet Drop Cable → Network Node
| System Component | Function |
|---|---|
| Allen-Bradley 1786-TNCJI4 | Provides an isolated jack-to-jack TNC bulkhead connection |
| 1786-TNCLP4 | Provides a TNC plug-to-plug adapter for connecting compatible TNC interfaces |
| 1786-TNCL10 | Provides a male TNC coaxial cable connector |
| 1786-TNCJ4 | Provides a conventional TNC jack-to-jack bullet connection |
| 1786-TNCLXT4 | Provides a 75-ohm TNC terminating resistor |
| 1786-BNC2TNC | Provides an isolated BNC-to-TNC bulkhead connection |
| 1786-TCT2BD1 | Provides an IP67 TNC tap with a straight BNC drop connection |
| 1786-TPST2T | Provides a straight TNC-to-TNC ControlNet tap |
| 1786-TPRT2T | Provides a right-angle TNC-to-TNC ControlNet tap |
| 1786-RG6 | Provides the main ControlNet coaxial trunk cable |
| 1786-RPFS | Provides short-distance fiber communication between network sections |
The 1786-TNCJI4 is particularly relevant where the network cable must cross a grounded cabinet wall or equipment panel and the shield isolation requirement must be maintained.
The 1786-TNCJI4 is suitable for ControlNet installations where coaxial cable connections pass through grounded panels or enclosure walls.
| Industrial Application | Typical Use |
|---|---|
| Automotive Manufacturing | Routing ControlNet coaxial connections through grounded production-line control cabinets |
| Steel Manufacturing | Maintaining isolated coaxial interfaces in electrical control enclosures |
| Power Generation | Connecting ControlNet cables through grounded panels in control rooms |
| Oil and Gas Automation | Providing isolated media connections between equipment enclosures |
| Chemical Processing | Maintaining shield isolation in distributed process control cabinets |
| Water Treatment | Connecting coaxial network sections through grounded electrical enclosures |
| Packaging Machinery | Providing panel-mounted ControlNet interfaces between machine sections |
| Industrial Drive Systems | Maintaining isolated coaxial connections near drive control equipment |
| Material Handling | Routing ControlNet media through grounded conveyor control panels |
| General Manufacturing | Establishing isolated bulkhead connections in existing ControlNet installations |
During maintenance, pay particular attention to the isolation arrangement around the panel mounting point. Replacing the bulkhead connector with a conventional TNC coupling may change the intended grounding and shielding configuration.
| Component | Function |
|---|---|
| Allen-Bradley 1786-TNCJI4 | Isolated TNC jack-to-jack bulkhead connector |
| Allen-Bradley 1786-TNCJ4 | TNC jack-to-jack bullet connector |
| Allen-Bradley 1786-TNCLP4 | TNC plug-to-plug connector |
| Allen-Bradley 1786-TNCL10 | TNC coaxial connector plug |
| Allen-Bradley 1786-TNCLXT4 | TNC 75-ohm terminating resistor plug |
| Allen-Bradley 1786-BNC2TNC | Isolated BNC-to-TNC bulkhead connector |
| Allen-Bradley 1786-TCT2BD1 | IP67 TNC tap with straight BNC drop cable |
| Allen-Bradley 1786-TPST2T | Straight TNC-to-TNC ControlNet tap |
| Allen-Bradley 1786-TPRT2T | Right-angle TNC-to-TNC ControlNet tap |
| Allen-Bradley 1786-RG6 | Standard ControlNet RG-6 coaxial cable |
| Model / Product | Product Type | Typical Application |
|---|---|---|
| Allen-Bradley 1786-TNCJ4 | ControlNet TNC Jack-to-Jack Connector | Inline connection between two TNC cable sections |
| Allen-Bradley 1786-TNCLP4 | ControlNet TNC Plug-to-Plug Connector | Joining compatible TNC jack interfaces |
| Allen-Bradley 1786-TNCL10 | ControlNet TNC Coaxial Connector Plug | Terminating TNC coaxial cable ends |
| Allen-Bradley 1786-TNCLXT4 | ControlNet TNC 75-Ohm Terminator Plug | Terminating compatible TNC network segments |
| Allen-Bradley 1786-BNC2TNC | ControlNet BNC-to-TNC Isolated Bulkhead Connector | Connecting BNC and TNC media interfaces through a panel |
| Allen-Bradley 1786-TCT2BD1 | ControlNet Media IP67 TNC Connector Tap | Providing a sealed ControlNet tap connection |
Both connectors use jack-to-jack TNC interfaces, but their mounting arrangements differ. The 1786-TNCJ4 is a bullet-style inline connector, while the 1786-TNCJI4 is an isolated bulkhead connector intended for installation through grounded panels where shield isolation is required.
In some industrial installations, the coaxial cable shield must remain electrically isolated from the grounded enclosure. The isolated bulkhead arrangement helps prevent an unintended shield-to-panel connection while maintaining the coaxial signal path.
Yes. Rockwell Automation’s ControlNet IP67 installation arrangement shows the 1786-TNCJI4 used with the 1786-TCT2BD1 tap assembly and a 1786-TNCLP4 plug-to-plug adapter. This configuration allows the tap connection to interface with the isolated bulkhead.
No. The 1786-TNCJI4 is an isolated coaxial coupling connector, not a terminating resistor. For a compatible TNC 75-ohm termination, the 1786-TNCLXT4 is the appropriate component.