ABB Installation Products 756LR-M0270 35kV, 600 Amp, Deadbreak Elbow, Cable Insulation Diameter 1.370 - 1.630 inches, Aluminum…

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How to Install 756LR/776LR Deadbreak Elbow Connectors

This guide provides step-by-step instructions for the safe and proper installation of 756LR and 776LR Deadbreak Elbow Connectors on 35kV class systems, including cable preparation, component assembly, grounding, and post-installation voltage testing.

Estimated time: 1h 30m

1. De-energize and Inspect Components

   DANGER: Ensure all apparatus is de-energized during installation or removal. Do not touch or move energized products. Inspect the elbow, cable adapter, compression lug, and mating parts for damage, correct rating, and compatibility. Remove any protective shipping covers and replace with appropriate HV insulated caps or connectors before energizing or submerging the circuit.

2. Position and Clean Cable Jacket

   Position the cable so it is located in the final assembled position with enough slack to provide adequate clearance for removing the elbows. Cut the cable 1-3/4” (45mm) from the centerline of the mating product. Clean the outer jacket of the cable for a distance of 24” (610mm).

3. Prepare Cable Insulation and Shield

   Prepare the cable end by removing the outer jacket (where applicable) and shield as shown in the specific cable preparation diagrams (e.g., non-jacketed concentric neutral, jacketed shield wires, flat metallic tape shield, fabric tape shield, or longitudinally corrugated shield). Bevel the end of the cable insulation at a 45-degree angle, approximately 1/4” (6mm) back.

4. Clean, Lubricate, and Install Cable Adapter

   Thoroughly clean and then lubricate the cable insulation, always working toward the semi-con shield. Install the cable adapter, small end first, until it is flush with the edge of the tape marker.

5. Prepare Conductor and Crimp Compression Lug

   Remove the protruding cable insulation by cutting it even with the end of the cable adapter. Do not cut or nick the cable adapter or the conductor. The length of exposed conductor should be between 4-3/8” to 4-3/4” (111mm-121mm). For copper conductors, fully insert the conductor into the compression lug. For aluminum conductors, wire brush the conductor and immediately fully insert it. Measure the “Check Dimension” before crimping (should be less than 7” or 178mm). Crimp the compression lug following its supplied instructions. Wipe all excess inhibitor from the lug and cable adapter surface after crimping. The distance from the end of the compression lug to the cable adapter after crimping should be between 6-7/8” to 7-5/8” (175mm-194mm).

6. Lubricate and Install Elbow

   Lubricate the cable adapter and the inside of the elbow cable entrance. Install the elbow onto the cable adapter until the elbow cannot advance further. Make sure the cable adapter is still flush with the tape marker. If not, reposition the cable adapter. Remove the tape marker.

7. Connect Elbow to Apparatus Bushing

   DO NOT CONNECT OR DISCONNECT MATING PRODUCTS WHILE ENERGIZED. DO NOT ENERGIZE WHILE DISCONNECTED. Remove protective caps from the elbow and the mating part. Hand tighten the threaded stud supplied with the elbow into the mating part, if the mating part is not equipped with a stud. Clean and lubricate both the elbow and the mating part with the supplied lubricant. Push the elbow onto the mating part, lining up the hole in the compression lug with the stud on the mating part.

8. Connect Second Mating Product (if applicable)

   If connecting a second mating product to the opposite end of the elbow, clean and lubricate it. Insert the mating part into the elbow, engage the threads, and hand tighten. Torque the mating part according to the instructions supplied with that mating part.

9. Install Insulating Plug or Voltage Detection Cap

   If an insulating plug is used as a mating part, clean and lubricate the inner surface of the voltage detection cap. Place the cap on the elbow and push down hard until it snaps into place. This insulating plug provides a means for detecting system voltage.

10. Ground the Cable Shield and Waterproof Jacket

    Insert one end of a piece of wire with ampacity at least equivalent to No. 14 AWG Copper through the grounding eye and twist to make a small loop. Do not damage the eye. Connect this wire to ground using a suitable connector. The shield of the cable must be grounded according to the instructions supplied with the grounding device or through an alternate method. It is also recommended that the jacket of the cable be waterproofed at this point to prevent moisture from entering the cable.

11. Perform Voltage Test Using Capacitive Test Point

    CAUTION: The voltage test point is a capacitance device, not directly connected to the conductor. Remove the test point cap with a hotstick, peeling it off at an angle. Use a suitable sensing device, made for use with separable connectors manufactured with capacitive test points, to determine if the cable is energized. Do not use conventional voltage measuring equipment. Treat the elbow as energized until the “no voltage” test point indication is confirmed by other means. After voltage detection, clean and lubricate the inside surface of the cap with silicone lubricant and replace it on the test point.

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