A U Sparky
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Master Electricians.
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A U Sparky
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Newsletter:
New edition of the Wiring Rules Standards Australia has released a 2007 edition of the Wiring Rules. This new edition is entitled AS/NZS 3000:2007, and are required as a mandatory basis from June 2008. All contractors are to be fully conversant with AS/NZS
3000:2007. • Extended application of Residual Current Devices (RCDs) and testing for correct operation • Protection against arcing faults • Requirements for selectivity (discrimination) between circuits • Strengthening of requirements for the prevention of the spread of fire • Enhanced requirements for recessed luminaires • Requirements for sanitisation areas in the food processing industry • Inclusion of detailed guidance material removed from the 2000 edition • More intuitive index, additional appendices, illustrations and background information.
Downlights! The new rule book highlights minimum requirements. Downlights and Recessed Lights. Australian Wiring Rules AS/NZS 3000:2007. Section 4.5.2.3 Recessed Luminairs. Recessed luminaire clearances Clause 4.5.2.3 now requires that recessed luminaries and auxiliary equipment be installed in a manner designed to minimise temperature rise and prevent the risk of fire (generally below 93o C). The temperature rise at the rear of a recessed luminaire shall be limited to prevent damage to adjacent combustible materials. This requirement shall be satisfied by one of the following methods: (a) The use of a luminaire specifically designed and certified by the manufacturer to permit — (i) contact with combustible materials; or (ii) enclosure or covering by thermal insulation material, as appropriate to the location of the luminaire. (b) Installation of the luminaire within a suitable fire-resistant enclosure. (c) Provision of required clearances from combustible and thermal insulating material as specified by the manufacturer of the luminaire. (d) Provision of the default clearances from combustible and thermal insulating material as specified in fig 4.7. Where manufacturer’s installation instructions that specify required clearances are not available, the luminaire shall be installed in accordance with (b) or (d). Recessed luminaires and their auxiliary equipment shall be installed in such a manner that air movement through or around the luminaire is not impaired by thermal insulation or other material. Where thermal insulation is of a type that is not fixed in position, e.g. loose fill, a barrier or guard constructed of fire- resistant material shall be provided and secured in position to maintain the necessary clearance (see Figure 4.7) Where thermal insulation may reasonably be expected to be installed in the space containing a recessed luminaire, the luminaire shall be installed in such a manner as to provide for subsequent installation of thermal insulation. Recessed luminaires shall be installed in accordance with (a) or (b), or provided with equivalent protective measures, where there is likelihood of extraneous combustible material, e.g. leaves or vermin debris, etc., collecting on or around the luminaire. Note: Due to Building Code of Australia requirements, you can no
longer guarantee that thermal insulation, in particular, the loose fill type,
will not be installed. Always check that electrical cables nearby remain fixed outside the default distances of figure 4.7. AS/NZS Clause 2.5.1 Insulating ceiling F mark, symbol Recess luminaire with this F mark are suitable for mounting on normally flammable surfaces where thermal insulating may cover the luminaire. All recessed lights not marked with the symbol should have a warning notice on an attached label or given in the manufacture’s instruction leaflet supplied with the luminaire, that the luminaire shall, under no circumstances, be covered with insulation matting or similar material.
Additional information
Areas that fall into the requirement of the above clause “where
there is a likelihood of extraneous combustible material, e.g. leaves or vermin
debris, etc., collecting on or around the luminaire” are: Building eaves or
within 1m of the eaves and where there is loose fill insulation under an open
tiled roof.
Actual debris found around a downlight
2. AS/NZS 60598.1 and AS/NZS 60598.2.2 detail the test method and the
maximum surface temperatures permitted for recessed luminaires. These maximum
temperature limits must be satisfied to permit any reduction in the default
values.
Some recessed luminaires will accept a range of lamp wattage and
types of lamp. These fittings unless clearly marked to show the type and maximum
wattage of the lamp to be fitted must be installed for the worst situation.
AS/NZS 60598.2.2 Particular requirements – Recessed luminaires,
Clause 2.5.1 Insulating ceiling F mark symbol
Recessed luminaires with the F mark are suitable for mounting in
normally flammable surfaces where thermal insulation may cover the luminaire. Note: Recessed luminaires not marked with the symbol shall have a warning notice on an attached label or given in the manufacturers instructions supplied with the luminaire that the luminaire, shall under no circumstances, be covered with insulation matting or similar material.
Fig 4.7 Default Minimum Clearances for Recessed Luminaires.
These clearances must be maintained unless the light fitting comes with documentation showing that insulation or building materials can be closer, this documentation must be kept. There are several light fittings that are available suitable to be used with insulation such as fibrous bats or mats but loose, Blow in, Insulation can move and you cannot guarantee the depth of insulation so we believe you must use a suitable barrier to maintain minimum distances in these cases. Notes: 1 National Building Codes require the installation of thermal insulation in many situations. 2 AS/NZS 60598.1 and AS/NZS60598.2 detail the test method and the maximum surface temperatures permitted for recessed luminaires (light fitting). These maximum temperature limits must be satisfied to permit any reduction in the default values of Figure 4.7 3. in Qld it is a requirement now for all new homes to have insulation so if your Electrician installs a down light or recessed light they MUST make sure it will meet these standards. It is the responsibility of your electrical contractor to make sure your lights they install meet these standards. Feel free to take the time to talk to our Team about your project before starting. Some of the other items the new wiring rules require. Clause 5.5.1.3 Labelling of the main earthing connection The main earth connection shall have a permanent label attached at the connection to the electrode with legible warning against disconnection in the following form: WARNING: ‘MAIN ELECTRICAL EARTHING CONDUCTOR-DO NOT DISCONNECT’ Note: the label is required to last the life of the building. The label must be made of a material that resists mechanical damage and environmental conditions.
Safety Switches. Changes in the new edition reflect the increasing use of residual current devices "Safety Switches"(RCDs) to all socket outlets and lighting circuits rated up to 20 A and include restricting the number of circuits that can be connected to any one RCD and the required division of lighting circuits over RCDs." The Wiring Rules legislate specific requirements to ensure that electrical devices, including RCDs, are installed and function safely, but this is a living document that's regularly updated to ensure it's always current on safety and best practice. In fact, we're waiting for the revised version to be released right now. The new Wiring Rules regulate the use of RCDs more stringently than before, contractors should make sure they understand what's required of them when installing RCDs. There is a danger of overlooking the changes and just designing and installing earth leakage systems like they've always done over the previous five, ten or twenty years. The fact is, RCD regulations have changed since many contractors were trained on them. So if they don't keep abreast with changes in the regulations, they're likely to either install them incorrectly, or struggle with requirements they weren't trained on. Either way, if they don't keep up with these changes, the consequences could be disastrous". This now means no more than 3 circuits on each safety switch.
Testing. Fault Loop Impedance. Fault loop impedance testing must be carried out as part of any electrical work that involves the connecting of a appliance or outlet to a circuit to guarantee the Electrical safety of a circuit. AS/NZS 3000 Wiring Rules applies throughout Australia and New Zealand and is referenced in whole or in part in legislation in all states of Australia and in New Zealand, as a minimum requirement. To that extent, the electrical circuit design and electrical installation of
these circuits must meet the requirements of the Wiring Rules standard. Automatic disconnection of the power supply is the most common method of achieving this. To comply with Clause 1.7.4.3.3 of AS/NZS 3000 Wiring Rules, each circuit in an electrical installation must be designed and protected so that automatic disconnection of the power supply will occur within the specified time when a short circuit of negligible impedance occurs between an active conductor or an exposed conductive part anywhere in an electrical installation. To fulfil this requirement of AS/NZS 3000 Wiring Rules when a fault current flows, the impedance of the fault current path (referred to in AS/NZS 3000 Wiring Rules as the Fault Loop Impedance Path) must be low enough to allow sufficient current to flow to cause the protective device to operate within the specified time. Understanding Loop
Impedance and Why it is Important
Measuring or calculating loop impedance is essential
when determining the prospective short circuit current in a circuit so that the
correct overload protection is used. A fundamental question must be answered “WILL THE
PROTECTION DEVICE FUNCTION DURING A FAULT CONDITION?” To determine the fault current rating for an overload device the maximum current that can be delivered to that point must be considered. Loop impedance at that point and the previous protective device will determine the correct rating. In a short circuit the overload device must be able to withstand that current before tripping. In other words the protection device must not melt , the contacts must not weld together while the fault is present and the device must be capable of opening under fault conditions. Prospective short circuit current measured in an
installation is used to consider whether the circuit is capable of carrying
sufficient current so as to trip the overload device in the specified time. Loop
impedances can be calculated as per appendix B of the Wiring Rules or measured
with a suitable test instrument. Using a test instrument may give you a more
accurate reading of the circuit because it will include all factors in the line
such as bad connections and back e.m.f.s generated by adjacent electrical lines
and other loads being present on the system at the time of the test Note that
impedance on the active and neutral lines are dynamic due to other sub circuits
attached to that line and their changes. The earth impedance without the MEN
connection would be constant. Using the loop impedance values, the tripping time of circuit breakers or fuses in the circuit can be determined. Clause 1.7.4.3.4 of the wiring rules states the required maximum times for circuit disconnection.
Using a loop impedance meter is useful in determining if the breaker can carry
the load during the time it takes to open the circuit and determine the time the
overload device could take to open. Using a loop impedance meter is optional
according to the wiring rules. However its use is essential for testing
installations and will improve confidence and safety in ensuring that overload
protection will operate correctly. It is also very useful in fault finding such
as locating loose connections. Your Electrical Contractor must have the tools to test and
record your fault loop impedance for all circuits worked on. Smoke Alarms. See our information at Mr Smokey web page. Click here for link. www.mrsmokey.com.au 16/11/2008 Brisbane Storm
Surge Protection:
Surge protectors
There are different levels of protection to consider, also the incorrect choice can create more damage if you have more than one surge protector, they can actually increase the voltage when a spike hits, ask us if you have any questions, we are happy to assist. Clipsal Lifesaver Emergency Light
Call the A U Sparky team on 07 3200 7111 for more details. On the Lighter side if you like your wines. We must admit we have sampled and do enjoy, (In moderation).
We (sometimes) deny they named there wines after us because of the quantity we consume.
Au Sparky and Telstra Xora Case Study.
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