Heat Shrink Rain Shed
Silicone rubber rain sheds for extending creepage distance at outdoor MV and HV cable terminations in polluted, coastal and industrial environments. Hydrophobic, UV stable and tracking resistant per IS 13573 and IEC 60502-4.
Why Rain Sheds are Required
The creepage distance of a cable termination — the surface path length from conductor to earth — determines whether the termination can withstand surface pollution and rain without flashover. Standard cable termination kits provide a defined creepage length for light pollution environments. In coastal, industrial or heavily polluted areas, the required creepage distance is 20–32mm per kV (IS 13573 pollution class e/a2 and e/a3) — often more than the standard termination provides. Rain sheds are disc-shaped silicone rubber skirts that slot over the termination tube and increase the surface creepage path without extending the cable height. Each shed increases creepage by the shed diameter-to-diameter difference (top to under). VIKCHEM manufactures rain sheds in single, double and triple configurations for the full voltage range of MV cable termination kits.
Pollution Level Guide
| Pollution Level | Environment | Min. Creepage | Sheds Needed |
|---|---|---|---|
| Light (e/a1) | Urban, inland, low humidity | 16mm/kV | Single |
| Medium (e/a2) | Coastal, industrial | 20mm/kV | Double |
| Heavy (e/a3) | Salt spray, chemical plants | 25mm/kV | Triple |
Key Features
- Silicone rubber material — inherently hydrophobic, does not absorb water or contaminants
- Sheds rain water effectively — prevents continuous water film from forming over the termination
- Extends creepage distance without increasing physical height of termination
- UV and ozone resistant — maintains performance after 20+ years outdoor exposure
- Tracking resistant — tested per IEC 60587; does not carbonise under sustained surface arcing
- Available in single, double and triple shed configurations for different pollution levels
- Fits over heat shrink termination tubes after shrinking — retrofit friendly
- Suitable for terminations from 6.6kV to 36kV system voltage
Applications
Outdoor Switchgear Terminations
Creepage extension at MV cable terminations entering outdoor ring main units and switchgear.
Coastal Installations
Protection against salt-laden air and sea spray at substations near coastlines.
Industrial Pollution Zones
Added creepage for cable terminations in cement plants, chemical works and foundries.
Desert and Arid Regions
Protection against dust and sand contamination on terminations in desert climates.
Transformer Yard Terminations
Outdoor creepage enhancement at incoming cable terminations on power and distribution transformers.
Overhead Line Down-Lead Cables
Protecting the down-lead cable section at pole terminations in heavily polluted areas.
