Electrical Safety

(from Gartner Superlux Training Manual)

All mains voltage light fittings sold in New Zealand must comply with electrical safety requirements laid down in the electrical codes of practice, which are cited under law in the Electricity Act.   This means a registered electrician who must hold a current practising licence must connect all luminaires to the supply.   A person wishing to have a luminaire/light fitting installed by an electrician can ask to see this licence and if the electrician does not produce it, they can refuse their services.   A householder may install a light fitting or electrical wiring, provided it has been inspected and passed by a registered person with current practising certificate.

 Any person doing electrical work can be asked to produce a current practising licence(which looks like a credit card)

EXTRA LOW VOLTAGE (ELV)

Because ELV lighting is considered electrically safe there is no requirement for an electrician to do the work, unless the mains voltage side of the installation needs connecting.  The reason for this is that 230 volts can easily cause electrocution whereas ELV cannot.   However, there are still inherent dangers in ELV lighting in relation to heat and selection of the right cable sizes.   A 50 watt 12 volt dichroic lamp draws 4 amps of current and if the wiring is not of sufficient size it can over heat and even cause fires, especially when more than one lamp is run off the same transformer.

TRANSFORMERS

A transformer is an electrical device, which converts from one voltage to another.   They are either copper-iron (ferro-magnetic) or electronic.   Transformers are labelled with their operating wattage, which must not be exceeded.   The markings typically say either '50 watts' or '50va', which means the same.   As an example a 200 va transformer would run four, 50 watt lamps.  It is usually considered best to run only one lamp per transformer.   This is because, when one lamp fails the voltage can rise on the remainder and shorten their life.

Special transformers such as 'toroidal' types overcome this but are more expensive.

DOUBLE  INSULATION

Another symbol, often used, is the double - insulated fitting mark:

This symbol means that the luminaire is safe  without an earth,  as it incorporates non-conductive elements.   An earth connection on a metal light fitting ensures that the circuit breaker trips if a loose wire contacts a metal part.   Loose wires cannot contact metal in double - insulated fittings, so they do not need earthing. 

 Read the Electrical Safety Brochure on the MoED Energy Safety website