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These days, use of electricity in Korea is being increased in proportionate to its economic development so in order to meet with this increasing demand of electricity, power plants (nuclear, thermal, hydraulic, anthracitic, gas) can¡¯t help being newly built up. At midnight, consumption of electric power is reduced, which causes waste of generated power so in order to efficiently use power being wasted, Korea Electric Power Corporation fixes low electric rates and supplies electric power to those who need it. This is the midnight electric power system.
(1) Midnight electric power is available for 10 hours from 22:00 to 08:00 hours.
(2) Midnight electric power is applicable only to midnight electric devices.
(3) The midnight electric devices are fan heaters, hot waters, boilers, electric Ondols, water boilers, and ice thermal storage system.

(1) Midnight electric power (A)
It is applicable to regenerative or ice thermal storage electric equipment only from 22:00 to 08:00 hours (hereinafter referred to as ¡°midnight application time¡±).

(2) Midnight electric power (B)
It is suitable for those who use regenerative or ice thermal storage electric equipment mostly during the midnight application time and during any other time than the midnight application time.
In principle, the low pressure supply method is 1-phase, 2-wire, 220V. Except for the case that firm power is supplied first in 3-phase or that a customer who is within the distance of 200m (underground 50m) installs a 3-phase midnight power device under 3-phase electric power, 3-phase, 4-wire, 380V can be supplied.
Firm Power

Consistent power supply for residential, business, industrial, and agricultural use, apart from midnight power supply.

Interior wiring

Electric wiring from KEPCO¡¯s supply point to electric equipments including ground service line, service entrance wiring, and circuit breaker.


Power meters, time switches, and magnetic contactors combined with time switches

Service Entrance Wiring

Wiring from supplying point to circuit breaker

Common Wiring

Common wiring for firm power and midnight power

Exclusive Wiring Wiring only for midnight power supply.