Suspension Insulator
- Porcelain ball-and-socket disc insulator for suspension & tension strings
- Links into strings — add discs to reach the line voltage
- ANSI 52-3 (70 kN) and 52-5 (120 kN) M&E ratings
- IEC 60120 16 / 20 mm ball-and-socket coupling
- For 11 kV up to EHV by stacking discs
- Brown glaze, radio-influence and puncture tested
Technical Specifications
| Catalog | ANSI Class | M&E (kN) | Disc Ø (mm) | Spacing (mm) | Creepage (mm) |
|---|---|---|---|---|---|
| RAX-DS-70 | 52-3 | 70 | 255 | 146 | 320 |
| RAX-DS-100 | 52-4 | 100 | 255 | 146 | 320 |
| RAX-DS-120 | 52-5 | 120 | 280 | 170 | 370 |
| RAX-DS-160 | 52-8 | 160 | 280 | 170 | 440 |
| Custom | Other sizes / configurations — send your conductor & structure spec | ||||
Application & Installation
Where it is used
The suspension (disc) insulator is a porcelain ball-and-socket cap-and-pin unit that links into a string to insulate and support the conductor at suspension and dead-end points. Discs are stacked to reach the required voltage, so one disc type serves many line classes — the standard transmission insulator.
Installation sequence
- Select the disc class (M&E) for the line tension.
- Count the discs needed for the system voltage and pollution.
- Couple the discs ball-into-socket and fit the locking keys.
- Connect the string to the tower via a ball / socket clevis.
- Hang the suspension or tension clamp at the conductor end.
Buyer’s Guide: Suspension Insulator
1. What a Suspension Insulator Is
A suspension (disc) insulator is one cap-and-pin porcelain unit with a ball on one end and a socket on the other. Units couple into a string; the number of discs sets the voltage withstand, while each disc's M&E rating sets the string's mechanical strength.
2. M&E Rating: 52-3 vs 52-5
ANSI 52-3 is rated 70 kN (15,000 lb) for 11–33 kV and lighter loads; 52-5 is 120 kN (25,000 lb) for 33–69 kV and heavier loads; 52-8 (160 kN) for the heaviest. Match the class to the line tension, not just the voltage.
3. How Many Discs
Disc count comes from the system voltage and pollution — more discs for higher voltage and dirtier air. A rough guide is one disc per ~11–15 kV, increased for coastal / industrial sites; follow the line design.
4. Ball-and-Socket Coupling
Discs couple via IEC 60120 16 / 20 mm ball-and-socket joints with a locking key. The same coupling lets our ball / socket clevis, ball eye and yoke fittings attach the string to the tower and clamp.
5. Porcelain vs Glass
Porcelain discs are robust and the traditional choice; toughened-glass discs (see our glass suspension insulator) shatter visibly when punctured, easing inspection. Both share the same ANSI classes and coupling.
6. Pairing
Build the string with ball / socket clevises, a yoke plate for V or double strings, and the suspension or tension clamp at the conductor end — all in matching coupling size.
