The FN7-12 indoor high-voltage load switch-fuse combination unit is a gas-generating type switch designed for 12kV, 50Hz three-phase AC power systems. It integrates a load switch and fuse, enabling it to interrupt load currents and close short-circuit currents, providing efficient protection for distribution transformers and switchgear in medium-voltage systems.
| Rated voltage(kV) | 12 | ||
| Rated insulation level voltage |
Power frequency 50Hz withstand voltage 1min (kV)
1.2/5us impulse withstand voltage (kV) |
Phase-to-phase,
Phase-to-phase, |
Isolation break 48
Isolation break 85 |
| Rated current (A) | 400 | 630 | |
| Rated short-time withstand current (kA, 4S) | 12.5 | 20 | |
| Rated peak withstand current (kA) | 31.5 | 50 | |
| Load switch, earthing switch, closing capacity (kA, peak) | 31.5 | 50 | |
a. Ambient air temperature: upper limit: +40℃; lower limit: -10℃ in general areas, -25℃ in high-cold areas;
b. Altitude: 1000m or less.
c. Relative humidity, daily average not more than 95%, monthly average not more than 90%;
d. Ambient air should not be significantly polluted by corrosive or flammable gases and water vapor;
e. No frequent severe vibration.
