These Pin Insulators are made by the wet process using high grade raw materials. The basic raw materials that go into the manufacture of these insulators of these insulators are naturally occuring clays and minerals like quartz and feldspar. The coarsely-powdered materials are ground to the required particle size in ball mills. The moisture content is reduced in filter process to obtain solid cakes. The cakes are fed into the pug mills. The void free pugs that are extruded from the pug mills are then pressed into shape and glazed after drying. These insulators which are thoroughly inspected before glazing are fired in the tunnel kilns.

The body composition developed over the years ensures excellent mechanical and electrical characteristics. These insulators are provided with Zinc thimbles suitable for Small and Large Steel Head Pins. Above Pin Insulators are subjected to a full series of type tests such as Impulse and Power Frequency Tests, Temperature Cycle Test, Mechanical (cantilever) test, Puncture Test & Porosity Test. Full quality control is exercised at all stages of manufacture. Some of the tests conducted on all insulators during manufacture are crack detection before firing, high frequency high voltage test besides routine electrical test at power frequency, in addition, porosity and temperature cycle tests are conducted for each batch of manufacture.

These pin insulators conforms to specifications, BS:137, IEC:383, IS:731 and other international specifications.


Standard Particulars
Product No. UT-P1111 UT-P1112 UT-P1114 UT-P1115
Highest System Voltage kV 12 12 12 12
Total Creepage Distance (Nominal) mm 270 320 230 320
Protected Creepage Distance (Nominal) mm 120 140 110 140
Cantilever Strength kN 10 10 10 10
Flashover Voltage Power Frequency Dry kV 70 75 65 75
Wet kV 40 45 38 45
Impulse Positive kVp 105 110 105 110
Negative kVp 110 120 110 120
Withstand Voltage Power Frequency Dry kV 65 70 60 70
Wet kV 35 40 35 40
Impulse Positive kVp 95 100 95 100
Negative kVp 105 110 105 110
Power Frequency Puncture Voltage kV 105 110 105 110
Visible Discharge Voltage kV 9 9 9 9
Thimble Type : IS:2486 (Part-II)/ BS:3288 (Part-II) Small or Large Small or Large Small Small or Large
Nett Weight (Approx.) kg 1.8 2.3 1.5 2.5
Contents of each package Nos 8 6 10 8

Applicable Specifications IS:731 BS:137 & IEC:383
Note : Insulators can also be supplied with Radio Free Glaze.


Export packing of insulators in pallets