Trefoil clamps are specifically used for high-voltage single-core cables, especially when three-core cables are not available. Sumip Trefoil clamps facilitate the laying of single-core cables in a touching formation, which maintains magnetic symmetry and minimizes electromagnetic heating and current loss. These clamps are molded from glass fiber filled material.

Short Circuits and Short Circuit Testing

The forces experienced by a cleat during a short circuit depend on the short-circuit current, cleat spacing, and the distance between the cable centers. In the case of trefoil arrangements, this distance is the cable diameter.

Sumip cable cleats undergo rigorous short-circuit testing and have been certified to withstand short-time and peak withstand test currents of up to 50 kA RMS and 125 kA peak at 1000 mm spacing for 1 second, as tested by the Electrical Research and Development Association (ERDA). This certification positions Sumip’s cleats as among the strongest in the market.

Sumip also offers clamps tested at 50 kA RMS and 125 kA peak at 1000 mm spacing for 3 seconds. Additionally, specialized clamps for organizations like POWERGRID and WBETCL are available, featuring nonmagnetic hardware and neoprene rubber lining in accordance with IS 111491987.