Long Rod Insulators

Long Rod insulators are used in applications in place of conventional string insulators.  For HV applications, conductors are usually supported on the transmission towers by means of disc insulators in the form of strings.  The string of disc insulators provides a maximum leakage distance and prevents flashovers across the insulator.

With the use of composite material for the manufacture of insulators, the string insulators are being increasingly replaced with long rod insulators.  Long rod insulators appear similar to the string insulators.  However, they are manufactured in a single piece.  The insulator consists of a "long rod" usually of Fibre reinforced Plastic (FRP) to bear the insulator load.  This rod is designed to have high tensile strength.

The housing of the insulator is usually made of silicone rubber or similar material.  The end fittings of the insulator are directly crimped on to the FRP rod.  Long rod insulators are puncture proof and have high arc resistibility. 

Long Rod insulators are lighter than strings of disc insulators of a similar voltage rating. Long Rod Insulators are used in both HVAC and HVDC applications.