Line Post Type Insulator

The Line Post Type Insulator 57-4S/57-4L is an ANSI C29.7 standard line post insulator with short and long stem options. Its rated voltage is 55 kV. The disc diameter is 165 mm, and the mechanical failing load reaches 12.5 kN. The creepage distance is 1015 mm, while the dry arcing distance is 368 mm.

The short stem version (S type) has a structure height of 430 mm. The long stem version (L type) has a structure height of 500 mm. These two height options allow engineers to select a suitable insulation distance according to different tower designs and installation conditions.

The 55 kV class is widely used in high voltage transmission and distribution systems. The porcelain body provides stable electrical insulation and mechanical strength under outdoor operating conditions. This Line Post Type Insulator is commonly installed on straight towers, tension towers, and other 55 kV overhead line structures.

We have established production experience with ANSI high voltage post insulators. Tall porcelain structures require careful control during forming, drying, and firing processes. Our factory uses controlled firing procedures to reduce deformation risks and maintain consistent product dimensions.

Our quality team performs dimensional inspections, including shed size, structure height, and mounting interface measurements. We also conduct bending load tests on production batches to verify the 12.5 kN mechanical performance.

Our measuring equipment checks product geometry and helps maintain accuracy between different production batches. We keep inspection records for quality tracking and can provide factory test reports according to customer requirements.

The dual-height design allows flexible project selection. Customers can choose the S type or L type according to installation space, conductor arrangement, and insulation requirements. This product has been supplied for overseas power transmission projects using ANSI standards.

The standard delivery time is 35 to 50 days. Due to the larger structure size, we recommend customers arrange orders according to their project schedule.

We support FOB and CIF trade terms. Each unit is packed in reinforced wooden cases with internal fixing supports. The packing design helps protect the porcelain body and mounting parts during long-distance transportation.

We provide export documents, product inspection records, and technical information according to shipment requirements. The warranty period is 12 months after shipment.

The Line Post Type Insulator provides two stem height options, stable porcelain performance, and ANSI standard compliance for 55 kV high voltage transmission applications.

All products support custom dimensions, voltage ratings, OEM/ODM services, and manufacturing based on drawings.