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As load shedding is again part of our daily lives, people are reverting to generators for backup power.
Please be advised that most portable generators sold in SA are VOV wound and may not be connected to a fixed electrical installation.

SANS 10142-1 states in clause 7.12.2.7 that a 230 V generator with a V-O-V earth connection (centre tap on winding which is earthed) shall
not be connected to a fixed electrical installation. Such a generator may only be used as a free-standing unit to provide power to specific appliances read more..

That been said, there are many companys connecting them with a change over switch to fixed installations.
Should an incident occur, all involved parties will be investigated and the homeowner could attract liability if
the installation is not safe or is not correctly used.
It could also invalidate the insurance on the property.

Note: Remember that any alternate power installation must be executed by a person registered with the DoL.
The registered person must issue a CoC upon completion of the electrical installation.

The size of inverter you require will be determined by power (wattage) you require.

Most appliances have a label showing the wattage symbol (W) (KW) (VA) (KVA)

If there is no wattage label, look for a current symbol (I) (Amps)

Multiply the voltage (230) x current (I) (Amps) = Watts

Use the calculator below to determine how many hours you can run during power outages, based on the number of batteries and power required.

Battery life of Deep cycle batteries are determined on how deep you discharge them.

Typical life span of Deep Cycle batteries are

  • 400 cycles at 50% depth of discharge
  • 200 cycles at 70% depth of discharge

A cycle is 1 discharge & 1 recharge.

As can be seen, the deeper the batteries are discharged the shorter the lifespan

Lead acid batteries take typically 9 hours to re-charge

  • Stoves
  • Ovens
  • Kettles
  • Geysers
  • Micro wave ovens
  • Toasters
  • Hair dryers
  • Air conditioners

These appliances have a high power consumption and would require very large inverters & large battery banks, which will be extremely expensive

Older type fridges have a high startup current or inrush current which may trip smaller inverters.

If you wan't to run your fridge, it is best to opt for a larger inverter which can handle the high startup current.

If one considers that load shedding is for 2,5hrs - 4,5hrs, it is not necessary to run the fridge

  • Replace all globes with LED's
  • Install a gas hob/stove
  • Install a gas geyser

This will reduce your power consumption dramatically which will reduce the cost of an inverter/battery system

and will also reduce your utility bill

The inverter can either be used as a stand alone system, where you connect appliances by means of an extension cord to the inverter

(see example below of a standalone system connected to a small D/B)

or you can connect the inverter to your Distribution board (Db) by means of a changeover switch.

This needs to be done by a qualified electrician, registered with the Dept of labour (DOD)

A Certificate of compliance (COC) must be provided for the installation

(See typical installations below)

Connected to Main D/B

Connected to a Sub D/B