The Short Version
If your transmission distance is under 15-20km and you are feeding a localized industrial zone or a medium-sized factory, 11kV is usually the more economical choice. If you are covering a wider area — say, a 50MW solar farm spread over several square kilometers, or a mining operation far from the nearest substation — 33kV will save you money on cable and reduce line losses over the longer run.
11kV Switchgear
11kV is the workhorse of medium voltage distribution. It is widely adopted across the Middle East, Southeast Asia, and parts of Africa. Most KYN28-12 switchgear we ship is configured for 11kV or 12kV systems.
What 11kV gives you:
- Equipment costs are typically 15-25% lower than 33kV equivalents — the switchgear panels are physically smaller, the bushings are shorter, and the cable terminations are simpler
- Cable costs are noticeably lower: 11kV XLPE cables are roughly half the price per meter of 33kV cables for the same current rating
- Transformers are more readily available and more standardized — 11kV/0.4kV distribution transformers are produced in massive volumes across China, India, and the Middle East
- Safety clearances are smaller — you need less space in your substation building
Where 11kV falls short:
- Voltage drop becomes an issue beyond 15-20km. At 11kV, every kilometer of cable drops roughly 0.15-0.2% of your voltage at full load — meaning you either upgrade your cable size or accept lower voltage at the far end
- For large loads above 15-20MW, 11kV switchgear starts to get bulky — you are dealing with very high currents (1000A+ per feeder) which means larger busbars, more heat dissipation, and bigger panels
33kV Switchgear
33kV is the go-to voltage level when distances stretch out. It is common in utility distribution networks, large solar farms, and mining operations. Our KYN61-40.5 switchgear handles 33kV and 35kV systems comfortably, and it is one of our best-selling products for African and Middle Eastern markets.
What 33kV gives you:
- You can push power over 30-50km without worrying about voltage drop — a real advantage for remote installations like mine sites, pipeline pumping stations, or large solar farms
- Line losses (I2R) are roughly 90% lower at 33kV compared to 11kV for the same power transfer — because you are transmitting at one-third the current
- You can handle higher loads through a single feeder — a 33kV, 1250A circuit can carry roughly 70MW compared to about 23MW at 11kV
The trade-offs:
- Switchgear panels cost more. A KYN61-40.5 panel runs about 20-30% higher than a KYN28-12 panel of equivalent rating — bigger vacuum interrupters, more insulation, larger enclosures
- Terminations and joints are more expensive and require more skilled labor — 33kV cable glands and terminations need trained technicians to install properly
- Safety distances are larger — your substation needs more physical space
Side-by-Side Comparison (Real Numbers)
| Parameter | 11kV System | 33kV System |
| Typical switchgear type | KYN28-12 (12kV class) | KYN61-40.5 (40.5kV class) |
| Max power per feeder (630A) | ~12 MW | ~36 MW |
| Max power per feeder (1250A) | ~23 MW | ~70 MW |
| Effective transmission distance | 10-15 km | 30-50 km |
| Switchgear panel cost index | 1.0 (baseline) | 1.2 – 1.3 |
| Cable cost index (same current) | 1.0 | 1.8 – 2.2 |
| Typical substation footprint (per panel) | ~1.2m x 2.5m | ~1.6m x 3.0m |
| Common in Middle East | Yes — 13.8kV also common | Yes — for long-distance transmission |
| Common in Africa | Yes — 11kV is standard | Increasingly adopted for new projects |
| Common in SE Asia | Yes — 12kV used in many countries | Used for utility primary distribution |
Practical Advice from the Field
In my experience working with contractors across different regions, here is what tends to work well:
For industrial plants and factories: 11kV is usually sufficient unless the plant draws more than 15-20MW or the incoming power line runs more than 10km. Most factories we supply to in Nigeria, Kenya, and Vietnam use 11kV switchgear.
For solar farms and wind projects: The collector network inside the plant often runs at 33kV — especially for larger installations above 10MW. The step-up substation will typically go from 33kV straight to 132kV or higher for grid connection.
For mining operations: 33kV is the safer bet. Mines tend to expand over time, and power demands grow. Starting at 33kV avoids having to re-cable and re-switchgear later.
For utility distribution: It depends on the existing network. In Saudi Arabia and the UAE, 13.8kV is widely used at the distribution level. In South Africa, 11kV and 22kV are both common. We always ask clients to check the local utility standard before ordering.
One More Thing to Keep in Mind
Do not forget to check the system earthing arrangement. 11kV and 33kV systems are typically resistance-earthed or solidly earthed depending on the utility standard. This affects your protection relay settings and the type of neutral-earthing equipment you will need. We have seen projects delayed because the earthing transformer was ordered late — so it is worth thinking about early.
Need help deciding between 11kV and 33kV? Get in touch with our engineering team.