Standoff Insulator
- Standoff / support insulator that holds a busbar or conductor off a frame
- Rigid post form with threaded inserts at each end
- For indoor / outdoor switchgear, busbar and equipment
- Porcelain or cycloaliphatic epoxy / composite
- LV to MV voltage classes; high cantilever strength
- Bolts between the live part and the earthed frame
Technical Specifications
| Catalog | Voltage | Height (mm) | Cantilever (kN) | Insert | Material |
|---|---|---|---|---|---|
| RAX-SO-1 | LV (1 kV) | 51 | 3 | M10 | Epoxy |
| RAX-SO-12 | 12 kV | 115 | 6 | M12 | Porcelain |
| RAX-SO-24 | 24 kV | 190 | 8 | M12 | Porcelain |
| RAX-SO-36 | 36 kV | 275 | 10 | M16 | Porcelain |
| Custom | Other voltages / inserts / cantilever — send your busbar spec | ||||
Application & Installation
Where it is used
The standoff (support) insulator holds a busbar, conductor or live part rigidly off an earthed frame in switchgear, substations and equipment. A rigid porcelain or epoxy post with a threaded metal insert at each end, it bolts between the live conductor and the structure, taking the cantilever and short-circuit forces while insulating the gap.
Installation sequence
- Select the voltage class and cantilever strength for the busbar.
- Bolt the base insert to the earthed frame.
- Bolt the busbar / conductor to the top insert.
- Confirm the post stands square and the clearances are met.
- Torque both inserts to the maker spec.
Buyer’s Guide: Standoff Insulator
1. What a Standoff Insulator Is
A standoff (support) insulator is a rigid insulating post that holds a live conductor or busbar a fixed distance off an earthed frame. With a threaded metal insert at each end, it both insulates the gap and mechanically carries the busbar against gravity and short-circuit forces.
2. Where It Is Used
In switchgear, substations, capacitor banks and equipment where a busbar or conductor must be supported and insulated from the frame. Indoor versions are common in panels; outdoor versions carry the weather.
3. Cantilever & Short-Circuit
Because the busbar is held at the top of a post, cantilever strength governs — and a fault current pushes busbars apart with large forces. Size the cantilever rating (3–10 kN) for the short-circuit force, not just the static weight.
4. Porcelain vs Epoxy
Glazed porcelain suits MV and outdoor duty; cycloaliphatic epoxy and composite suit LV / indoor and where impact or tracking resistance matters. Pick by voltage and environment.
5. Threaded Inserts
Metal inserts at each end give a bolted connection to the busbar and frame. Match the insert size (M10–M16) to the busbar hardware so the assembly bolts up cleanly.
6. Voltage Class
LV (1 kV) up to 36 kV here, with height and creepage rising with voltage. Confirm the clearances and creepage suit the equipment voltage and pollution.
