The Hilti S-BT-ER (HC) HL and S-BT-EF (HC) HL screw-in threaded studs are widely used for electrical connections in the following applications:

• Functional bonding and terminal connection in a circuit For permanent current (leakage current) due to static charge built up in pipes or when closing an electrical circuit.
• Protective bonding circuit For discharging short circuit current while protecting electrical equipment or earth / ground cable trays and ladders.
• Lightning protection For high temporary current due to lightning.

The technical data such as minimum base material thickness, maximal cross section of connected cable, maximum current and connection configuration can be found in Section 3.2.15.6 of the North American Product Technical Guide, Volume 1 [1].

The technical data given in the Technical Guide section [1] apply to steel base materials with a tensile strength fu = 360 MPa - 760 MPa (50 ksi to 110 ksi) and base material thickness tII ≥ 6.0 mm (1/4”.)

The S-BT-ER (HC) HL and S-BT-EF (HC) HL studs for electrical connections are tested only on steel base material. However, the electrical conductivity of copper is much higher than that of steel. The thermal conductivity of copper is also better than that of steel. This means that the heat can be dissipated faster.

The electrical performance values published in Hilti Technical data [1] for steel can also be applied to copper base material. To help prevent corrosion, Hilti recommends using only the S-BT-ER (HC) HL made of stainless steel in copper base material. To fasten the S-BT-ER (HC) HL, use the instruction for use (IFU) directions for fastening in aluminum base material utilizing the step drill TS-BT 5.5-74 AL, item no. 2143138. The tightening torque of the nut should be limited to 8 Nm.

Customers are advised to evaluate the suitability of the proposed recommendations and solutions from Hilti based on their application requirements.