| N/O | DETAIL | DATA | |
| 1 | Description | 11 kV Combi Drop Out Fuse link and Lightning Arrestor Assembly complete with Mounting Accessories (Integrated Unit) | |
| 2 | System conditions of service |
|
|
| a) nominal Voltage (Un) r.m.s | kV | 11 | |
| b) maximum system voltage (Um) r.m.s | KV | 12 | |
| c) number of phases for each unit | 3 | ||
| d) Frequency | Hz | 50 | |
| 3 | Site conditions of service | ||
| a) altitude | m | 1400 | |
| b) Operating Ambient temperature | °C | -1 to 40 | |
| c) Humidity | % | 85 | |
| 4 | Rating | ||
| a) Nominal voltage | kV | 11 | |
| Dielectric strength | |||
| Lightning impulse withstand (1.2/50) | kV | 95 | |
| Power frequency wet withstand voltage r.m.s | kV | 28 | |
| 5 | Built in mechanism to drop-out in the event of arrestor failure | Yes/No
|
Yes |
| 6 | Mechanical interlock to avoid closing the fuse when the arrestor is out provided |
Yes/No |
Yes |
| 7 | Surge arrestors and Fuses operable from the ground |
Yes/No |
Yes |
| 8 | Minimum Specific Creepage Distance for insulators | mm/kV | 25 |
| 7 | Accessories | ||
| Drawings and brochures showing | |||
| outline and general arrangement of the Combi Unit (Integrated Unit) | Yes/No
|
Yes | |
| 8 | b) Detailed drawings of all items of the Combi Unit (Integrated Unit) showing critical tolerances to be provided with bid | Yes/No | Yes |
| 9 | Previous Type test report/certificate on Combi Unit (Integrated unit) to be provided with bid |
Yes/No |
Yes
|
| 10 | Routine tests on Combi Unit (Integrated) (acceptance tests on sample
Product) to be provided on delivery |
Yes/No | Yes |
| 11 | Applicable standard | PIESA 002, BS EN ISO 4521, IEC 60815 | |
| 12 | Other applicable standards | NRS 035
SABS IEC 60282-2 SABS IEC 60186 BS 137 part 2 |
|
| Compliance to Clauses 5, 6.1, 8,8.1,9,10,11 and 12 | Yes/No | Yes |
11KV DROP OUT FUSE LINK ASSEMBLY TECHNICAL GUARANTEES
| N/O | DETAIL | DATA | ||
| 1 | Description | 11 kV Fuse link assembly complete with fuse carrier rated at 100A | ||
| 2 | System conditions of service |
|
||
| a) nominal Voltage (Un) r.m.s | kV | 11 | ||
| b) maximum system voltage (Um) r.m.s | KV | 12 | ||
| c) earthing | Effective & non effective | |||
| d) Frequency | Hz | 50 | ||
| 3 | Site conditions of service | |||
| a) altitude | m | 1400 | ||
| b) Operating Ambient temperature | °C | -1 to 40 | ||
| c) Humidity | % | 85 | ||
| 4 | Rating | |||
| a) Nominal voltage | kV | 11 | ||
| b) Rated current | Fuse carrier | A | 100 | |
| Cut out base |
A |
200 |
||
| 5 | Electrical components | |||
| a) Insulator material specification to IEC 60815 | Silicon Rubber polymeric type | |||
| Dielectric strength | ||||
| Lightning impulse withstand (1.2/50) | kV | 95 | ||
| Power frequency wet withstand voltage r.m.s | kV | 28 | ||
| 6 | Specific creepage distance | mm/kV | 25 | |
| 7 | General information to be provided with bid:
Drawings and brochures showing outline and general arrangement |
Yes/No | Yes | |
| b) Detailed drawings of all items showing critical tolerances to be provided with bid | Yes/No | Yes | ||
| 8 | Previous Type test report/certificate on complete fuse link assembly to be provided with bid |
Yes/No |
Yes |
|
| 10 | Routine tests (acceptance tests on sample
Product) to be provided on delivery |
Yes/No | Yes | |
| 11 | Applicable standard | PIESA 002, BS EN ISO 4521, IEC 60815 | ||
| 12 | Other applicable standards | NRS 035
SABS IEC 60282-2 SABS IEC 60186 BS 137 part 2 |
||
| Compliance to Clauses 5, 6.1, 8,8.1,9,10,11 and 12 | Yes/No | Yes | ||
11KV LIGHTNING ARRESTOR TECHNICAL GUARANTEES
| S/N | TECHNICAL DETAILS | UNITS | DATA | |
| 1. | Type | 11kV gapless type metal oxide surge arrester – Distribution class | ||
| 2. | Nominal system voltage | kV | 11 | |
| 3. | Highest system voltage | kV | 12 | |
| 4. | Power frequency | Hz | 50 | |
| 5. | Basic Insulation Level (BIL) | kV | 95 | |
| Ratings and type of surge arrester | ||||
| 6. | Specification to which surge arrester complies | IEC 60099 | ||
| 7. | Rated voltage of surge arrester | kV | 10 | |
| 8. | Nominal, 8/20 µs, discharge current rating of surge arrester | kA | 10 | |
| 9. | Maximum continuous operating voltage of surge arrester | kV | 7.3 | |
| 10. | Gapless or gapped type metal-oxide surge arrester | Gapless | ||
| 11. | Insulation Material to IEC 60815 | High temperature vulcanized Silicon rubber | ||
| 12. | Cantilever strength of surge arrester | Nm | 300 | |
| 13. | Rated frequency of surge arrester | Hz | 50 | |
| 14. | Design altitude of surge arrester (above sea level) | m | 1400m | |
| 15. | Design ambient temperature of surge arrester
|
oC | -1 to 40 | |
| 16. | Minimum phase-to-ground specific creepage distance of surge arrester
|
mm/kV | 25 | |
| Automatic earth lead disconnectors requirements
|
||||
| 17. | Automatic earth lead disconnectors fitted | Yes/No | Yes | |
| 18. | Corrosion protection of metal and alloy parts: galvanising specification and/or stainless steel grade | To SABS 763, 316 | ||
| Tests | ||||
| 19. | Previous Type Test reports/certificate from recognized authority to be provided with bid | Yes/No | Yes | |
| 20. | Minimum one minute wet power frequency withstand voltage of external insulation of surge arrester housing | kV | 70 | |
| 21. | Maximum steep current impulse residual voltage for a 10 kA, 1/20 µs, discharge current | kV | 99.7 | |
| 22. | Maximum lightning impulse residual voltage for a 10 kA, 8/20 µs, discharge current | kV | 91.8 | |
| 23. | Lightning, 1,2/50 µs, impulse withstand level of external insulation of surge arrester housing | kV | 170 | |
| 24. | Line discharge class rating | Class | 1 | |
| 25. | Long duration current, 2 000 µs, impulse withstand | A | 250 A | |
| 26. | High current, 4/10 µs, impulse withstand | kA | 100 kA | |
| 27. | Is the automatic earth lead disconnector tested in accordance with IEC 60099-4? | Yes/No | Yes | |
| 28. | Compliance to Clauses 5, 6.1, 8,8.1,9,10,11 and 12 | Yes/No | Yes | |
Integrated Protection
Combines a surge arrester and a drop-out fuse in one compact assembly, simplifying installation and improving system reliability.
Fail-Safe Drop-Out Mechanism
Automatically isolates the phase if the arrester fails or reaches end-of-life, ensuring the transformer is never left unprotected.
Reduced Nuisance Fuse Operations
Correct surge diversion through the arrester prevents unnecessary fuse blowing during lightning events.
Quick & Safe Maintenance
All operations (fuse replacement, inspection, isolation) can be performed from the ground using a hot-stick—no climbing required.
Lower Lifecycle Cost
Fewer outages, quicker service restoration, reduced maintenance time, and longer arrester life result in significant long-term savings.
Compact and Easy to Install
The integrated design reduces mounting space, wiring complexity, and installation time on the pole.
High Performance in Harsh Environments
Equipped with polymer silicone insulators, high creepage distance, and IEC-compliant electrical ratings—ideal for high lightning and heavy pollution areas.
Enhanced Network Reliability
Minimizes transformer failures, reduces customer interruptions, and improves overall feeder performance.
Standardized Field Replacement
Fuse links and arrester modules are interchangeable and easy to replace, ensuring fast restoration after faults.
Widely Accepted by Utilities
Proven technology used by power utilities across Africa, Asia, and South America.
Distribution Transformer Protection
Installed on pole-mounted transformers (11kV & 33kV) to provide combined overcurrent and surge protection.
Rural and Long-Feeder Networks
Ideal for long overhead lines prone to lightning strikes, voltage surges, and difficult maintenance access.
High Lightning Density Areas
Protects transformers and distribution lines in regions with frequent thunderstorms by reducing surge-related failures.
Network Reliability Improvement Programs
Used by utilities to reduce SAIDI/SAIFI indices through faster isolation, fewer outages, and quick restoration.
Harsh Environmental Conditions
Suitable for coastal, industrial-pollution, desert, and high-humidity zones due to polymer insulators and high creepage distance.
Fault Isolation on MV Distribution Poles
Provides clear visual drop-out indication of arrester or fuse operations for accurate troubleshooting.
Compact Installations and Space-Limited Poles
Perfect where separate fuse cut-outs and surge arresters are difficult to mount due to limited pole space.
Upgrading Aging Distribution Infrastructure
Replaces old porcelain arresters and traditional fuse cut-outs with a modern, integrated, safer solution.
Renewable Energy Rural Electrification Projects
Widely used in mini-grid, solar farm, and rural electrification schemes across Africa and Asia.
Industrial and Commercial Distribution Transformers
Protects customer-owned transformers in factories, estates, farms, and commercial facilities.
A Combi Unit is an integrated device that combines a surge arrester and a drop-out fuse in a single assembly, providing both overcurrent protection and lightning surge protection for distribution transformers.
The integrated design ensures proper surge diversion, reduces nuisance fuse blowing, saves pole space, and provides a fail-safe system if the arrester fails.
If the surge arrester reaches end-of-life or fails due to a severe surge, the unit automatically drops out, isolating the faulty phase and preventing unprotected transformer operation.
Yes. They are designed for lightning-prone regions and offer high impulse withstand levels, making them ideal for Africa, Asia, and tropical climates.
Yes. All operations—such as fuse replacement or isolation—are designed for hot-stick (link-stick) operation from ground level.
Yes. Combi Units are designed to work with commonly used expulsion fuse links for both 11kV and 33kV networks.
They follow IEC 60099-4, IEC 60282-2, IEC 60815, PIESA, NRS, and other regional utility specifications depending on customer requirements.
Absolutely. The clear drop-out indication and easy ground-level operation greatly reduce fault-finding and restoration time.
Yes. They are widely used as a modern upgrade for traditional porcelain arresters and separate fuse cut-outs.
On overhead distribution poles feeding 11kV or 33kV transformers—especially in rural, coastal, industrial, or high-pollution areas.
