On the back side of most gadgets, there’s a string of hieroglyphs that look like the bottom line of an engineer’s eye chart. But this mishmash of electrical symbols and letters is essential to international trade, product performance and safety.

All electrical switches including dimmers must have the following mandatory electrical symbols to comply with South African and International Standards.  Products which show these symbols must be able to produce a valid test report and an RCC or LOA number.  Conversely, all mains dimmers must have a valid RCC or LOA number.

Here’s what each electrical symbol means and why it’s on there.

Shuttle Lighting Logo

Manufacturer’s or responsible vendor’s name, trade mark or identification mark



Type or model number


The unique product model number must be on the label and must correspond with the model number on the LOA or RCC

RCC or LOA Number

RCC or LOA Number

Mandatory to have, not mandatory to show on the label

South African Regulatory compliance certificate number

SANS 60669-2-1

South African National Standard

Mandatory to have, not mandatory to show on the label

Specification is drawn up by SABS and is adopted from the IEC.  SANS is an umbrella specification which covers a list of specifications such as EMI


Ingress protection rating

Mandatory to show on label

First number: protection rating from solids

Second number: protection rating from water


Nominal operating current

Mandatory to show on the label if the rated load is not shown

Will differ for different wattages of products

~ 230VAC, 50Hz

Voltage and frequency

Mandatory to show on label

A voltage of (nominally) 230 V and a frequency of 50 Hz is used in Europe, most of Africa, most of Asia, much of South America and Australia.

The wave symbol is for AC voltage

Incandescent Light Symbol

Incandescent lamps

Mandatory to show on label

Indicates what type of lamp the dimmer can be used on

LED Lamp Symbol

LED Lamp


A voluntary symbol, which shows that the dimmer is compatible with LED’s

Electronic step-down converter Symbol

Electronic step-down converter

Mandatory to show on label for compatible products

Shows that the dimmer is compatible with electronic transformers

Terminated Load Symbol

Terminal for regulated load

Mandatory to show on label

Shows that the output voltage is variable which means that a non-dimmable product cannot be connected to the dimmer

The importance of electrical symbols:

With the wide variety of bulbs and dimmers now available on the market it is important to choose your products wisely. Pairing dimmers and lamps which are incompatible can result in lights flickering and fluttering, limited dimming range, slow start-up, and inconsistent illumination.

To avoid these types of issues it is important to remember these five things when pairing dimmers with LED lamps:

  • Not all LED lamps are dimmable. Make sure yours are
  • Not all controls work with dimmable LED lamps. Read the manufacturer’s compatibility charts
  • Some LEDs are just cheap and unproven. Buy well-tested products
  • Some dimmers are cheap and unproven. Buy well-tested products
  • Always perform a mock-up