Load-shedding becomes necessary when the national electrical demand on the network is greater than Eskom’s capacity to supply. It is critically important to keep the demand below the national supply capacity. It is therefore imperative that load forecasting is done in conjunction with a host of other criteria that will affect hourly load projections and balance this with the available supply capacity. This function is done by Eskom’s National Control Centre which monitors this dynamic 24/7 and issues instructions to maintenance crews, planners, strategists, large industrial customers and various other personnel to maintain this balance. Only as a last resort and when every other attempt to balance the supply and demand has failed, will load-shedding be introduced to prevent a national grid collapse which could take days to restore. Load-shedding is an urgent response to an emergency, hence advanced notice is not possible.

EThekwini Load-shedding schedules are drawn up in accordance with the national guideline document (NRS 048-9) with specific consideration to technical constraints, practicality and sensitivity to local economic impact. The current schedule comprises of Stages 1 to 8 and blocks 1 to 16 A & B. These are largely residential and commercial loads. These blocks are scheduled for a 2-hour period per block. 

There are predominantly industrial areas designated from block 17 to 20 which only shed from stage 7 upwards in 4-hour blocks. This has been done to protect industry from continuous interruptions. 

During load-shedding we urge customers to switch off high-demand appliances like geysers, stoves, air-conditioning etc. so as to ensure that the waiting load at the time of restoration is not high. High waiting loads can result in a protection trip of individual circuits which will require staff to be dispatched to the point of supply and therefore will result in an extended outage time for all customers on that circuit.