A 70 kN standard profile disc with 127 mm spacing, 255 mm diameter and 320 mm creepage, weighing 3.6 kg. The volume workhorse for transmission and sub-transmission lines in clean and mild pollution.
Mechanical, electrical, radio influence and packing values as tested to IEC 60383 and GB/T 1001.1.
| Mechanical Failing Load | 70 kN |
|---|---|
| Spacing H | 127 mm |
| Diameter D | 255 mm |
| Creepage Distance | 320 mm |
| Ball And Socket Coupling Size | 16 |
| Wet Power-frequency Withstand Voltage | 40 kV |
| Dry Power-frequency Withstand Voltage | 70 kV |
| Dry Lightning Impulse Withstand Voltage | 100 kV |
| Puncture Withstand Voltage | 130 kV |
| Test Voltage RMS To Ground | 10 kV |
| Maximum RIV At 1000 kHz | 50 microvolt |
| Corona Extinction Voltage Pin/Cap | 18/22 kV |
| Power Frequency Arc | 0.12 s / 20 kA |
| Net Weight | 3.6 kg |
A toughened glass disc bonded to a hot-dip galvanized steel cap and steel pin with a zinc sleeve, using high-strength alumina cement cured in a 70 degrees C water bath for about one hour.
The U70BLP shares the same 70 kN rating and 16 coupling but carries 450 mm of creepage instead of 320 mm, at 5.3 kg instead of 3.6 kg. If the route crosses coastal or industrial air, the extra 1.7 kg per disc is the cheaper option.
Toughening sets the mechanical rating, the thermal shock test removes defective shells, cementing fixes the fittings, and every finished unit is tested before it is packed.
Shells are heated close to the softening point, then high-pressure air jets cool the surface rapidly while the core cools slowly. The surface ends in compression at roughly 100 to 200 MPa with the core in tension, giving four to five times the mechanical strength of ordinary glass.
Shells are heated to about 300 degrees C and plunged into cold water, a drop of roughly 420 degrees C. Any unit carrying internal stress or an inclusion shatters here rather than in service. Survivors move on and the broken glass is recycled as cullet. A second thermal shock test follows to IEC 60383-1 and GB/T 1001.1.
A hot-dip galvanized steel cap, steel pin and zinc sleeve are bonded to the toughened disc with high-strength alumina cement, then cured in a 70 degrees C water bath for about an hour so the cement develops full strength before handling.
Every finished insulator is checked visually for cracks, bubbles, chips and bonding defects, then tested electrically for high-voltage withstand, insulation resistance and partial discharge, mechanically for tensile, bending and torsion strength, and environmentally for thermal cycling, pollution resistance and UV ageing.
Assemble the string with the matching ball and socket coupling size 16 and confirm that the security clip is fully seated on every unit before the string is lifted.
In service, inspect visually on routine patrols. A self-destructed disc is visible from the ground and the steel cap and pin continue to carry mechanical load until replacement. Clean in heavily polluted areas and replace broken units in the next planned outage. No complicated preventive tests are required.
We supply installation manuals, technical drawings and, for large projects, on-site installation guidance and string assembly training.
Mr Andrey from Pradex visited the Jinhao plant in Linyi for a technical review covering the glass shell forming line, the toughening and thermal shock stations, the cementing line and the finished goods inspection area.
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127 mm spacing, 255 mm diameter, 320 mm creepage, 16 ball and socket coupling and 3.6 kg net weight at 70 kN mechanical failing load.
40 kV wet power frequency, 70 kV dry power frequency, 100 kV dry lightning impulse and 130 kV puncture withstand voltage.
It carries 30 kN more mechanical load and 130 mm more creepage, at twice the weight and 80 mm more diameter.
Yes. Colour, packaging and marking customization is available, as are custom creepage distances and special fittings for project-specific requirements.
Tell us the quantity and destination port. We will confirm lead time, packing configuration and the test report set that ships with the order.
