How to Identify Loadbreak Separable Connectors

Cable Accessories operating interfaces play a critical role in long-term electrical performance. Learn how you can increase performance with loadbreak separable connectors from Hubbell.

Loadbreak Separable Connectors

Cable Accessories, or separable connectors, like loadbreak elbows are size sensitive products from the way terminated cable fits into the cable entrance, and how the operating interface connects to its mating part. Both play a critical role in long term performance because the right fit will seal the electrical connection from moisture ingress, even when submersed in water.

The below shows a 15kV Class elbow. The operating interface includes the inner dimensions and probe to make sure the elbow will fit onto a 15kV Class junction or insert.

15kV Elbow Graphic

IEEE Std 386 designates operating interface dimensions for 15kV, 25kV or 35kV small and large interfaces. This includes the physical size and shape of the inner part of the elbow as well as the probe length and dimensions, which matters because joining or separating two matching parts at the operating interfaces is what makes or breaks electrical connection being carried on the cable.

In the image below, a 28kV elbow is closed onto a 28kV feed-thru insert. Similarly, 28kV elbow arresters are installed for protection on the opposite side of the elbow.

Distribution-Cable-Acc_appphoto87

Color Coding and Identification

Each interface also has an optional color-coding assigned for loadbreak connectors to help with identification in the field. If used, the colors can be found on nose pieces, interfaces and cuffs. If the cable accessories manufacturer uses these interface dimensions, the parts within these same voltage classes will fit together. Additionally, manufacturers are required to perform further switching and fault-closure tests to verify competing parts are fully interchangeable.

Voltage Class 15kV 28kV 35kV Small Interface 35kV Large Interface
Elbow Cable Accessories_15kv elbow Cable Accessories_27kv elbow Cable Accessories_35kv small elbow Cable Accessories_35kv large elbow
Elbow Color Hubbell chooses not to include the optional color on 15kV elbows Blue Gold Purple

If a 15kV probe is accidentally installed with a 28kV elbow, the probe will be too short to make contact with the mating bushing. However, if a 28kV probe is accidentally installed with a 15kV elbow, the probe will make contact too soon creating a dangerous environment for the installer.

It’s important to recognize there are two interfaces assigned to the 35kV Class – 35kV Small Interface and 35kV Large Interface. The two 35kV interfaces are not interchangeable. Besides their relative size to one another, these products are easily identified by the gold and purple cuffs as seen in the table above.

Benefits of Loadbreak Products from Hubbell

The table below summarizes a few of the common 200A Loadbreak products available by interface size.

Product 200A Loadbreak Interface
15kV 28kV 35kV Small Interface 35kV Large Interface
Loadbreak Elbow
Elbow Arrester
Bushing Insert  
Insulating Cap  
Junction    
Grounding Elbow

While some Cable Accessories manufacturers only offer one of the two 35kV interfaces, Hubbell is uniquely positioned to offer both interfaces for several products!

Hubbell offers a wide range of Cable Accessories products and has a team of experts available to support end users with product selection and specifications. Our underground separable connectors are designed and tested to meet or exceed all applicable requirements of IEEE, and other industry standards.

To learn more, visit our product pages or contact your Hubbell representative.



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