How A Post Insulator Works
A low voltage post insulator is made from ceramic material and works on two principles at once. The first is insulation performance, which prevents current passing through. The second is mechanical performance, which is the ability to withstand the weight of the wire and any external force applied to it. A post insulator that satisfies one and not the other has failed.
Where They Are Used
In power systems, low voltage post insulators support and isolate low voltage conductors on transmission and distribution lines. In industrial settings they support and isolate electrical equipment and lines so the equipment can run normally. The duty is the same in both places, but the mechanical loads and the environment often are not.
J8-125 Post Ceramic Insulator 8kN Bending Strength
Selecting By Voltage Level
Select the voltage level for the actual application so the insulation performance meets the requirement. This sounds obvious and is still the most common selection error, usually where a part is reused from a lower voltage part of the same installation.
Selecting By Mechanical Strength
Select the mechanical strength from the weight of the wire and the external forces expected, so the insulator can carry both. In our range this is published directly: 4kN minimum breaking force with 100N.m torsion strength on the C4-80 II, and 8kN bending strength on the J8-125.
C4-80 II 10kV Porcelain Post Insulator GOST
Selecting For The Environment
Temperature, humidity and corrosion all affect insulators, so the material and structure have to suit the environment. Climatic classification exists for exactly this reason, which is why GOST parts carry a UKhL execution class and an atmosphere type to GOST 15150-69.
IPU-10/630-7.5 I UKhL1 Wall Bushing With Oval Flange
Selecting By Quality And Supplier
Choose products of reliable quality so performance stays stable across a delivery and over time. In practice this means asking what proof loading is applied on routine test and what management systems the plant operates under, not just what the catalogue claims.
