Guide to
LED Lighting
Introduction
With the rapid change from traditional lamp types to more efficient LED (light emitting
diode) lighting and the large variety of lighting products available, the selection of
suitable LED light sources (lamps) and LED luminaires (light fittings) for lighting
interior and exterior areas, offers the consumer many choices.
Product branding, where importers have the ability to mark products with the brand names
of their choice, complicates the issue as it is difficult to evaluate such brands based on past
experience with products from the same manufacturer. Although products from leading
lighting companies are readily available and are supported by extensive research and product
development programmes, the market offers a multitude of LED product brands. The suppliers
of many of these products make optimistic claims of light output and product life expectancy.
While product safety is very important, the reliable performance of the LED light source and
luminaire are essential for a good lighting installation; one that will allow occupants to move
around safely and perform tasks efficiently. The safety requirements for LED lamps and
luminaires are fairly clearly defined in standards and specifications and can be determined
through suitable testing and inspection. The luminaire and light source performance and
lifetime reliability are more difficult to determine and require extensive and costly testing.
Basic lighting concepts
To make the correct choice, it is essential that some basic concepts of lamps and lighting are understood.
Specifically in the case of LED lamps, aspects such as light output, colour and colour rendering, lamp efficacy and life expectancy should be considered to justify the higher expense of LED lighting when compared with traditional
lamps.
Life expectancy
LEDs emit visible light when electricity is passed through a semiconductor. In this process, heat is generated that needs to be dissipated effectively to prevent overheating of the LED, which could result in reduced light output and
lamp life.
Some manufacturers make optimistic claims about their LED lamps’ life expectancy (25 000 to 50 000 hours are common claims). Because actual life testing is extremely costly and impractical, these claims are projections based on the life of the LED chip, when operating under temperature conditions as specified by the LED chip manufacturer. The design of the LED lamps or LED luminaires should therefore ensure that these conditions are not exceeded. Users should also understand that their operating environment may affect the life expectancy of the product.
Some manufacturers make optimistic claims about their LED lamps’ life expectancy (25 000 to 50 000 hours are common claims). Because actual life testing is extremely costly and impractical, these claims are projections based on the life of the LED chip, when operating under temperature conditions as specified by the LED chip manufacturer. The design of the LED lamps or LED luminaires should therefore ensure that these conditions are not exceeded. Users should also understand that their operating environment may affect the life expectancy of the product.
EMI (electromagnetic interference)
LED lamps emit electromagnetic energy and there are very clear
local and international specifications as to the maximum levels
of these conducted and radiated emissions. Exposure to high
frequency electromagnetic fields, even as low as 100 kHz, may
have health consequences. High EMI can also interfere with
electronic devices such as audio visual equipment, communication
systems and pacemakers, amongst others. For these reasons,
all lighting-related products must comply with international
compulsory standards – part of the European EMC directive –
or the South African SANS 215 standard of which ICASA is the
regulatory authority.
There are currently a large number of LED products on the South African market that do not comply with this standard and that, when installed, become a distributed source of high emissions.
There are currently a large number of LED products on the South African market that do not comply with this standard and that, when installed, become a distributed source of high emissions.
LED lamp dimming
Incompatibility between dimmers and LED lamps is often experienced by users. Where the following marking is displayed on LED lamp packaging, the dimming of such lamps is not allowed. Suppliers should be approached for technical advice on dimming.
- Light output, lumen: the total amount of light emitted from a light source or luminaire, (lm).
- Lumen maintenance, %: the rate of deterioration of light output of a lamp over time.
- Lamp efficacy, lumen/Watt: The amount of light emitted from a bare lamp (lm) divided by the input electrical
power (W).
- Lamp life, hours: The rated lamp life of lamps is generally based on the average life of a sample of lamps burning under controlled conditions. It gives the number of burning hours at which the sample of lamps maintains its claimed light output.
Colour characteristics
The colour characteristics of light emitted from light sources are described in various ways.
The colour rendering index depends on the spectral emission of light from the source over the visible range. A typical spectral emission curve for a white LED is given below. From the curve it is clear that the blue component is dominant and that there is lower emission in the green/yellow/red areas. This would lead to lower colour rendering of these colours.
- Correlated Colour Temperature (CCT) is a measure of the emitted light’s colour. This classification is commonly seen on LED lamp packaging and gives the user a choice of some lamp colours to suit different applications.
- Colour Rendering Index (CRI) is a rating Ra that is given to a light source and which represents the degree of colour shift that would be obtained when each of eight specified colour samples are illuminated by the light source and compared with the colour obtained with a reference light source.
A value of Ra= 100 means perfect colour rendition. For indoor lighting, the value of Ra should not be less than 75. Where the recognition of colour is important the LED lamps with the highest Ra value should be selected.
The colour rendering index depends on the spectral emission of light from the source over the visible range. A typical spectral emission curve for a white LED is given below. From the curve it is clear that the blue component is dominant and that there is lower emission in the green/yellow/red areas. This would lead to lower colour rendering of these colours.
The colour rendering index depends on the spectral
emission of light from the source over the visible
range. A typical spectral emission curve for a white
LED is given below. From the curve it is clear that the
blue component is dominant and that there is lower
emission in the green/yellow/red areas. This would
lead to lower colour rendering of these colours.
While there are many LEDs with different emission curves available, LEDs with good colour rendering index values should be selected where colour matching is important.
Luminaire and lamp suppliers/manufacturers should be contacted for technical advice.
LEDs can fail due to overheating if they are made from poor quality materials and if the heat from the LEDs is not dissipated efficiently. LED lamps with a greater light output are particularly prone to this problem.
While there are many LEDs with different emission curves available, LEDs with good colour rendering index values should be selected where colour matching is important.
Luminaire and lamp suppliers/manufacturers should be contacted for technical advice.
LEDs can fail due to overheating if they are made from poor quality materials and if the heat from the LEDs is not dissipated efficiently. LED lamps with a greater light output are particularly prone to this problem.
Compulsory standards/specifications for LED luminaires
VC8055: Electrical and electronic apparatus.
The following safety standards are compulsory by reference in VC8055 to the following safety standards:
SANS 60598-1: Luminaires Part 1: General requirements and tests.
SANS 60598-2-1: Fixed general purpose luminaires.
SANS 60598-2-2: Recessed luminaires.
SANS 60598-2-4: Portable general purpose luminaires.
SANS 60598-2-7: Portable luminaires for garden use.
SANS 60598-2-8: Hand lamps.
SANS 60598-2-9: Photo and film luminaires (nonprofessional).
SANS 60598-2-10: Portable luminaires for children.
SANS 60598-2-11: Aquarium luminaires.
The following safety standards are compulsory by reference in VC8055 to the following safety standards:
SANS 60598-1: Luminaires Part 1: General requirements and tests.
SANS 60598-2-1: Fixed general purpose luminaires.
SANS 60598-2-2: Recessed luminaires.
SANS 60598-2-4: Portable general purpose luminaires.
SANS 60598-2-7: Portable luminaires for garden use.
SANS 60598-2-8: Hand lamps.
SANS 60598-2-9: Photo and film luminaires (nonprofessional).
SANS 60598-2-10: Portable luminaires for children.
SANS 60598-2-11: Aquarium luminaires.
SANS 60598-2-12: Mains socket-outlet mounted nightlights.
SANS 60598-2-13: Ground recessed luminaires.
SANS 60598-2-18: Luminaires for swimming pools and similar applications.
SANS 60598-2-19: Air-handling luminaires.
SANS 60598-2-20: Lighting chains.
SANS 60598-2-23: Extra low voltage lighting systems for filament lamps.
SANS 60598-2-24: Luminaires with limited surface temperatures.
SANS 60598-2-25: Luminaires for use in clinical areas of hospitals and health care buildings.
SANS 1464: Luminaires for emergency lighting.
SANS 60570: Electrical supply track systems for luminaires. Various other standards for luminaires, lamps and lighting components are available. Information can be obtained from suppliers, the NRCS or the SABS.
Standards for LED lamps and control gear
The following standards and specifications apply:
SANS 60598-2-5: Floodlights
SANS 62560: Self-ballasted LED lamps for general lighting services by voltage >50 V – safety specifications (IEC 62560).
SANS 62031: LED modules for general lighting – safety specification (IEC 62031).
SANS 61347-2-13: Lamp control gear. Particular requirements for dc and ac supplied electronic control gear for LED modules (IEC 613437-2-13).
VC 9087: Compulsory specification for lamp control gear. (This specification refers to SANS 61347-1.)
SANS 1662: Self-ballasted LED tubular lamps for general lighting services for voltage >50 V – safety specification.
VC9109: Compulsory specification for energy efficiency and functional performance requirements of general service lamps (GSLS)
VC9110: Compulsory specification for safety requirements of general service lamps (GSLS)
SANS 60598-2-5: Floodlights
SANS 62560: Self-ballasted LED lamps for general lighting services by voltage >50 V – safety specifications (IEC 62560).
SANS 62031: LED modules for general lighting – safety specification (IEC 62031).
SANS 61347-2-13: Lamp control gear. Particular requirements for dc and ac supplied electronic control gear for LED modules (IEC 613437-2-13).
VC 9087: Compulsory specification for lamp control gear. (This specification refers to SANS 61347-1.)
SANS 1662: Self-ballasted LED tubular lamps for general lighting services for voltage >50 V – safety specification.
VC9109: Compulsory specification for energy efficiency and functional performance requirements of general service lamps (GSLS)
VC9110: Compulsory specification for safety requirements of general service lamps (GSLS)
Luminaire Safety
Luminaire safety requirements are set to prevent harm to persons or damage to property mainly through fire,
electric shock or burning. Users should be aware of important safety aspects in selecting luminaires, some of
which are listed below:
Luminaires shall be marked with at least the following:
- Manufacturer’s name, mark of origin.
- Lamp type and maximum wattage.
- Rated supply voltage.
- Any precautions for installation and maintenance.
Luminaires shall be one of the following classes:
-
- Class I: Protection relies on basic insulation only and must be provided with a protective earth conductor (line, neutral and earth).
- Class II: Protection relies on basic insulation
with additional double insulation or reinforced
insulation. No provision for protective earthing (line and neutral). Luminaires shall be clearly marked with the symbol:
The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing. This is usually accomplished, at least in part, by having two layers of insulating material surrounding live parts or by using reinforced insulation such as insulating sleeves, grommets and bushings. - Class III: Luminaires in which protection against electric shock relies on supply at safety extra-low voltage (SELV) and in which voltages higher than those of SELV (<50V) are not generated. Such luminaires shall be clearly marked with the symbol:
- Class O: Luminaires in which protection against electric shock relies upon basic insulation only are not permittedin South Africa.
The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing. This is usually accomplished, at least in part, by having two layers of insulating material surrounding live parts or by using reinforced insulation such as insulating sleeves, grommets and bushings.
Class I luminaires shall be provided with an earth terminal to which all accessible metal
parts, which may become live in the event of an insulation failure, are permanently and reliably electrically
connected. The earth connection shall be locked against accidental loosening
Luminaires shall be so constructed that their live parts are not accessible when the luminaire has been installed and wired as in normal use, and when it is opened as necessary for replacing
lamps.
LED lamp safety
For LED lamps with externally accessible metal parts,
these parts must be effectively insulated with reinforced
or double insulation to ensure protection against
accidental contact with live parts.
(SANS 62560: Some LED lamps have been found not to comply with this requirement, resulting in a safety risk.)
Compliance with this requirement can only be determined through testing.
The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing. This is usually achieved at least in part by having two layers of insulating material surrounding live parts or by using reinforced insulation such as insulating sleeves, grommets and bushings.
(SANS 62560: Some LED lamps have been found not to comply with this requirement, resulting in a safety risk.)
Compliance with this requirement can only be determined through testing.
The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing. This is usually achieved at least in part by having two layers of insulating material surrounding live parts or by using reinforced insulation such as insulating sleeves, grommets and bushings.
Who polices the lighting industry in South Africa?
- The Illumination Engineering Society of South Africa (IESSA) represents the interests of the South African lighting industry.
- The South African Bureau of Standards (SABS) sets the national standards.
- The National Regulator for Compulsory Specifications (NRCS) is mandated to set compulsory specifications and
carry out surveillance and compliance monitoring against these specifications.
- The Safehouse Association’s Peer Review Process supports member self-compliance in addition to regulatory requirements, to enhance the compliance of Safehouse members’ products. This process applies third-party surveillance testing to confirm detected non-compliances and to effectively initiate corrective action by the supplier.
What to look out for when buying LED products
Visible workmanship is usually an indication of
product quality and reliability.
- For lamps with accessible metal parts, such as
cooling fins and heat sinks, establish whether the
product complies with the relevant safety standard.
- If a product is materially cheaper than other, similar
products on offer, be wary.
- Be suspicious of excessive life expectancy claims
compared with products from reputable brands.
- Consult a qualified, registered electrician or electrical engineer for extensive installations, especially renovations and retro-fits.
- Do not buy products with poor earthing of
accessible metal parts or inadequate protection of
wiring of double insulated luminaires.
- Third party product certification, such as an SABS
mark, provides some comfort in the event of
premature product failure. (‘CE’ marking is not a
third party certification).
- Choose products from reputable, established
suppliers and look for brand names from known
manufacturers who have proven design and
manufacturing capabilities.
- If in doubt, contact the Safehouse Association for assistance.
Beware of deliberate or negligent misinformation
This non-compliant LED luminaire’s driver is marked with the double insulated marking, but
the supply leads only have basic insulation and are not marked.
About Safehouse
Safehouse is a non-profit organisation that protects South African businesses and people from preventable harm caused by unsafe electrical products and services.
We’re a voluntary group of electrical industry stalwarts, technical experts and leaders of our respective businesses and fields.We believe it’s our civic and commercial duty to protect our industry and fellow South Africans from suppliers of unsafe electrical products and services.
We work to eradicate dangerous products from the market, to make electrical safety information understandable and accessible and to hold one another, and our industry, to
the highest standards of excellence.
Safehouse members have signed a code of conduct that commits them to dealing only in safe electrical products and to responsible behaviour.
If you have doubts about a particular product or service, contact Safehouse for guidance. info@safehousesa.co.za
Product Design Basics
Owing to the high energy efficiency, extended life
expectancy, and colour variation available in LED light
sources, designs of all shapes and sizes with standard
lamp-cap configurations have become available to
replace existing ‘traditional’ lamps. In South Africa, this
changeover has gained impetus due to the energy crisis.
LED modules are extensively used in the manufacture of luminaires and are available in various configurations. The design of the luminaires should be such that temperature limitations, as specified by the LED module manufacturer, are maintained and insulation between the primary mains voltage circuit and the low voltage circuits are ensured, to prevent accessible luminaire parts from becoming live.
LED modules are extensively used in the manufacture of luminaires and are available in various configurations. The design of the luminaires should be such that temperature limitations, as specified by the LED module manufacturer, are maintained and insulation between the primary mains voltage circuit and the low voltage circuits are ensured, to prevent accessible luminaire parts from becoming live.
The replacement of other lamps with LED lamps in existing luminaires therefore
requires omni-directional LEDs, which are readily available with most of the
standard lamp-cap configurations. This has been achieved by mounting the LED
chips in the required directions and, in some instances by covering the entire
lamp with diffusers or lenses to disperse the light. It is therefore possible to retain
a luminaire’s photometric distribution characteristics and light output, through
the careful selection of LED lamps with omni-directional light distribution and
equivalent light output (lumen) provided the LED lamp has a similar shape and
similar dimensions as the original lamp for which the luminaire was designed.
