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HomeTips & GuidesAutomotive Bulkhead Electrical Connectors: How To Pass Current Across Barriers

Automotive Bulkhead Electrical Connectors: How To Pass Current Across Barriers

About Automotive Bulkhead Electrical Connectors: Have you ever encountered automotive bulkhead electrical connectors? They are crucial connectors that facilitate simple yet essential connections. Passing current through a barrier such as a PCB or solid surface is easy with such a connector. 

What does it look like, and what is its working principle? This comprehensive guide covers everything related to automotive bulkhead electrical connectors. 

What are Bulkhead Electrical Connectors?

They are specialized coaxial connectors that facilitate secure current transfer through a barrier. Think of them as links in applications requiring the connection of electrical components on either side of a barrier. 

In this case, the barrier could be a PCB, the mounting surface, or any form of an enclosure. Notably, the connectors are available in various variations, such as TNC, BNC, and SMA. They are usually metallic, an essential property to ensure they are long-lasting. 

In addition, the metallic material helps shield against electromagnetic interference (EMI), ensuring smooth current flow. Nonetheless, when they pass through the barrier, they have an insulation (usually rubber) to prevent short circuits. 

Finally, they sport threads on either end for easy connection to other electrical parts. 

Components of Bulkhead Electrical Connectors

Black Rubber Gaskets. 

Black Rubber Gaskets. 

While there are numerous types of bulkhead electrical connectors, they all share a similar basic structure comprising the following: 

  1. Body: This is the central part of the electrical connector and features threads on either end. You plug it into an exterior component. 
  2. Nuts: Although removable, they still count as primary parts of the connector. The nuts are handy when screwing it to another electrical part. 
  3. Gaskets are essential in plumbing connectors. However, they are also found in electrical connectors, where they primarily assist in creating tight joints. 

Types of Bulkhead Electrical Connectors

A bulkhead connector is in use. 

A bulkhead connector is in use. 

You’ll come across many types when shopping for a bulkhead electrical connector for your auto. Here are the main variations. 

Bulkhead Plugs

Ships feature connectors to facilitate barrier integrity. 

Ships feature connectors to facilitate barrier integrity. 

They are usually male head connectors and perfectly fit on female connectors on their other end. You will need these connectors in scenarios where preserving the barrier’s integrity is necessary. 

They are also straightforward to use, which is why they are popular in auto electrical work. However, note that they are not specialty bulkhead connectors for electrical current transmission. 

Specialty Bulkhead Electrical Connectors

Auto electrical cables. 

Auto electrical cables. 

It is the go-to bulkhead connector for auto electrical work. It is designed to facilitate smooth current flow across a barrier from one end of the connector to the other. When choosing a bulkhead electrical connector, ensure you get the gauge size. 

Your connector size should match the wire gauge of the wire you intend to plug into it. 

Bulkhead Wiring Connectors

Car electrical repair. 

Car electrical repair. 

It’s a bulkhead electrical connector type specially reserved for passing cables around a barrier. Often, such a connector features numerous connectors in one housing, which is important in ensuring the passage of multiple wires via the bulkhead. 

There are other types of (non-electrical) bulkhead connectors you might come across, such as: 

  • Tank Bulkhead Fittings
  • Double-Bulkhead Fittings
  • Standard Bulkhead Fittings

These are common in plumbing applications, so don’t buy them for electrical work, as they won’t work. 

Another classification of bulkhead connectors is whether they have threads on either end. Under this categorization criteria,  we have two types: 

  • Slip bulkhead fittings
  • Threaded bulkhead fittings

Materials for Bulkhead Electrical Connectors

A stainless steel bulkhead electrical connector. 

A stainless steel bulkhead electrical connector. 

You must also be careful when choosing your bulkhead electrical connector material. Why? Different materials feature different properties; some are unsuitable for auto applications. Below are the ideal materials for bulkhead electrical connectors:

  1. Aluminum – It’s one of the best materials for auto bulkheads because it’s corrosion-proof. Also, aluminum is naturally lightweight, which is important in autos where weight is a concern, such as aircraft. 
  2. Stainless Steel – While aluminum is ideal, stainless steel is even better, especially where corrosion is highly likely. The material also withstands corrosive chemical exposure and remains in shape even under extreme heat. 
  3. Copper is another excellent bulkhead electrical connector material thanks to its high conductivity. 

Benefits of Bulkhead Electrical Connectors

Why should you use bulkhead electrical connectors? There’s a bottomless pit of benefits that include the following: 

Outright Installation

A bulkhead connector on a ship's wall. 

A bulkhead connector on a ship’s wall. 

You won’t experience any hassle when installing these connectors. Simply plug it into the barrier you want to bypass, screw washers and bolts, and that’s all. The maintenance is also straightforward primarily because most are made from non-corrosive metals/materials. 

They Provide Flexibility

The primary upside of the connectors is that they provide a priceless way to pass current/wires across barriers. This flexibility is essential in auto electrical works. You can tidily pass your current/wire through anywhere in the car, simplifying wire engineering. 

Secure Connections

A secure bulkhead connector on the wall of a ship. 

A secure bulkhead connector on the wall of a ship. 

The bulkhead connectors feature threads on either side, which allow for a tight fit screwing to another electrical component. This property is essential in auto applications primarily because of the predominant vibrations. 

The connector threaded pattern means the components connected to it are immune to these vibrations. It also facilitates the maintenance of the transmitted signal’s integrity. 

Excellent Shielding from EM Waves

The metallic cover of the connector is designed to keep electromagnetic radiation at bay. It ensures that the surrounding radiations do not impact the signal-carrying wires. 

It is especially important when dealing with telecommunication cables. Such interruptions can constrain their functionality. 

How Do Bulkhead Electrical Connectors Work?

A drill with a screwdriver bit. 

A drill with a screwdriver bit. 

They create a pathway to bypass barriers such as PCBs or a cover on the auto’s body. Installation is also straightforward via the following key steps: 

  1. First, assemble the components you need for the installation. They include a drill, spanner, a bulkhead fitting, a gasket/washer, and a bolt. 
  2. Make a hole on the surface where you want to pass the bulkhead fitting. You must ensure that the hole diameter is slightly larger than the diameter of the connector’s central part. 
  3. Next, install the bulkhead electrical connector via the hole. You must secure it from either end, so start placing washers/gaskets, then nuts. Using a spanner, screw the bulkhead connector tightly, ensuring that it perfectly fits on the barrier. 
  4. It is now ready to connect other circuit parts on either end. Most importantly, ensure the bulkhead fitting is proportional to the wire gauge of the cable you want to connect. 

Applications of Bulkhead Electrical Connectors

Telecommunication equipment in a car. 

Telecommunication equipment in a car. 

  1. They are instrumental in telecommunication, primarily connecting antennas through barriers/walls. Their excellent joints against the barrier and shielding ensure signal integrity preservation. 
  2. Also, the connections are essential in wireless network applications, such as providing connections for WiFi access points. Specifically, they are handy in applications that require regular reconfigurations. 
  3. They are also valuable for auto applications, primarily for passing current around a barrier. 
  4. Fourthly, you will also find the connectors in industrial applications, primarily in passing signals across enclosure walls.


Bulkhead electrical connectors rank among the most critical components in the auto industry. Their ease of use and ability to create secure connections, even through barriers, make them exemplary in their work. So, if you have been seeking such a connector, we hope you’re well-guided. 

Hi I am Christa, sales manager of Cloom.

I have extensive expertise and experience in wiring harnesses and I believe I can help you.

And we have a very professional technical team who can clearly understand the customer’s needs and give professional suggestions and solutions after receiving the drawings.

If you also have wiring harness needs, please send me the drawing so that we can give you our quote and start our business.

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