Power to Air conditioner Units

RSA Bardo Electrical Systems (Pty) Ltd works together with Air Conditioning Company's by installing power to their units. These AC Units are deemed fixed electrical equipment.

Air conditioners require to be powered by their own circuit and an isolator needs to be installed withing arms reach of the air conditioner.

Every electrical installation requires the work undertaken, materials used and design to comply to the Wiring Code SANS 10142 and The Occupational Health and Safety Act.

Note: There is a large inrush current when an air conditioner kicks in, so a slow curve circuit breaker is recommended.

This  requires that a registered person as defined (mater electrician, installation electrician or electrical tester for single phase; will issue a Certificate of Compliance together with a test report.

The Certificate shall be in the form of the Certificate of Compliance published in the Electrical Installation Regulations, 2009 and the Test Report shall be in the form of the test report in SANS 10142 8.8

Air Conditioners come in different sizes, which means they all draw varying amounts of power. Current is an important factor when designing the installation especially the peak current.

AC single phase amps to kilowatts calculation

The power P in kilowatts (kW) is equal to the power factor PF times the phase current I in amps (A), times the RMS voltage V in volts (V) divided by 1000:

P(kW) = PF × I(A) × V(V) / 1000

AC three phase amps to kilowatts calculation

Calculation with line to line voltage       

The power P in kilowatts (kW) is equal to square root of 3 times the  power factor PF times the phase current I in amps (A), times the line to line RMS voltage VL-L in volts (V) divided by 1000:

P(kW) = √3 × PF × I(A) × VL-L (V) / 1000

The power P in kilowatts (kW) is equal to 3 times the  power factor PF times the phase current I in amps (A), times the line to neutral RMS voltage VL-N in volts (V) divided by 1000:

P(kW) = 3 × PF × I(A) × VL-N (V) / 1000

SANS 10142 6.16.4 Refers to Air Conditioning, Refrigeration, freezer units, extraction and ventilation fans states that dedicated circuits shall be provided for air conditioning units that are rated at more than 16Amps. There may be more than one unit on each circuit and the power supply to each unit shall be controlled by a switch-disconnecter (Isolator).

The Switch-Disconnecter (Isolator) must be correctly rated, taking into account the number of poles, and the environment must also be taken into account.

Some installations take into the inrush current, which may trip a standard curve circuit breaker (C Curve) so a slow curve circuit breaker (D Curve) would be installed.