Municipal electrical distribution systems are not designed for load shedding conditions. The design relies on randomly spread loads and infrequent switching for maintenance, fault finding, etc.
During Load Shedding switching happens up to three times per day, but the real killer is that the load is synchronised/ concentrated. All geysers, pumps, heaters, air conditioners etc. start simultaneously. The start-up current of rotating machines like pumps and compressors is up to three times higher during the first few seconds. It is this concentrated load that sometimes is high enough to trip a circuit breaker, but the peak current is also high enough to cause high voltage cable joints buried underground to fail.
So how do we protect ourselves against such trips and failures?
- Switch off all rotating machines, heaters and geysers before the planned reconnection time.
- When the power is restored wait a few minutes before boiling the kettle and resuming cooking.
- Switch geysers, pumps etc, on only after the power has definitely stabilised.
The above can be achieved by switching off all circuit breakers EXCLUDING LIGHTS during the power outage. The lights will confirm when the power is restored and other circuits can then be switched on gradually after power is stable. This will also protect electronic equipment such as TV sets and computers.
Tips provided by CDR Electrical