LICENCE for AS/NZS Electrical installations – Selection of cables – Cables for alternating voltages up to and including /1 kV – Typical. Electrical installations – Selection of cables – Cables for alternating voltages up to and including /1 kV – Typical Australian installation. The calculator calculates the short circuit fault current at a specified distance in a cable run, based on the source short circuit fault current level. See also the full.
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Click here for full conditions of Licence This is a licensed electronic copy of a document where copyright is owned or managed by Standards Australia International. A guide to the acceptable short-circuit temperature limits is given in Section 5. The higher operating temperature achieved by grouping will not affect the mineral insulation of the unserved cable. Alternative arrangements of the aas, e. Current-carrying capacities may also be determined by calculation using IEC and appropriate cable data.
In addition the values for bare conductors are based on nzzs weathered conductors and the values of insulated conductors are based on the use of black PVC.
Similarly, lower ambient temperatures may apply for cables installed in concrete slabs on or above the surface of the ground.
Refer to the tables of current-carrying capacity for the different cable types, Tables 3 to Furthermore, a still smaller supply voltage is required to maintain the given load voltage when the current leads the load voltage. Table 2 4 contains a reference to the appropriate current-carrying capacity table for cables installed in underground wiring enclosures.
Such cables, which would include earthing conductors, lightly loaded neutrals and unloaded control wiring, may be placed adjacent to, or between, groups of associated loaded conductors. However, in doing so the following factors which may determine the system to be selected are highlighted: The minimum cable size will be the smallest cable that satisfies the three requirements.
Under such conditions the current-carrying capacity given in Tables 3 to 21 shall be corrected by the application of an appropriate rating factor or factors obtained from Tables 22 to Method D would be operating at near maximum load. Determine which single-phase voltage drop values will apply when the cable is operating Licensed to BGC Cemtech on 25 Aug Storage, distribution or use on network prohibited.
These conditions have been used to derive the current-carrying capacities tabulated in Section 3.
Attention is drawn to the minimum bending radius recommended for the type of cable. New Zealand requests should be directed to Standards New Zealand. A significant amount of explanatory material is also provided on the application of rating factors which arise from the particular installation conditions of a single circuit or groups of circuits.
Therefore the voltage drop on a single-phase basis will only be that associated with the current flowing in one active conductor, i. 30008
Cable short circuit fault current calculator AS/NZS 3008
A specific installation condition is defined and illustrated and alternative installation conditions deemed to have the same current-carrying capacity are also given. This Standard Part 1. Actual values would need to be calculated according to loading. Guidance is given on the following aspects: For other types of cable installed in locations exposed to direct solar radiation it will be necessary to make some provision for the effects of the increased heating.
Consideration should also be given to the voltage drop at this operating temperature. Where there is more than one layer on the same tray or ladder support, Table 22 may be used. Where other ambient temperatures apply, the appropriate rating factors shall be as given in Table Suggestions for improvements to Joint Standards, addressed to the head office of either Standards Australia or Standards New Zealand, are welcomed.
Some situations where this will occur are as follows: For derating factors applicable to other arrangements of cables in underground wiring enclosures, refer to ERA Report or alternative specifications. Therefore, the minimum cable size would be 70 mm2. However, the cables are generally installed in areas of high ambient temperature, such as equipment wiring, and it will be necessary to apply an appropriate nzss correction factor from Table However, if work on an installation commenced before publication of this edition, the inspecting authority may grant permission for the installation to be carried out in accordance with the superseded edition.
In general, the current-carrying capacity requirement will be the most demanding in the relatively shorter route lengths of domestic premises and the like where factors such as semi-enclosed rewirable fuse protection, cable grouping, and thermal insulation occur.
Inclusion of copyright material in computer software programs is also permitted without royalty payment provided such programs are used exclusively in-house by the creators of the programs. The current-carrying capacities of served cables may be 1. ae
Where cables are to be operated at this temperature, care must be taken to nzd inadvertent contact with the hot surface of the cable and associated supports and terminations, and also to avoid subjecting the cable to mechanical stresses. Such backfill should completely surround the cable with a minimum thickness 308 mm and could be used in lieu of the bedding required in AS Different methods of installation vary the rate at which the heat generated by the current flow is dissipated to the surrounding medium.
However, the current-carrying capacity of neutral-screened aerial cables shall be determined as follows: Longitudinal expansion of a cable during a short circuit can be significant and when this expansion is restrained the resultant forces are considerable. Click ass to sign up.
Cable short circuit fault current calculator AS/NZS |
The actual derating factor in this situation may be closer to 0. Taking into account the method of installation employed, the smallest conductor size which has a tabulated current-carrying capacity equal to or in excess of this predetermined minimum value will be considered to be the minimum cable size satisfying the current-carrying capacity Licensed to BGC Cemtech on 25 Aug Each Part zs a complete Standard and requires no reference to the other.
Where the continuous loading of the cables is assessed as 16, 20, 25, 32, and 40 amps, determine the minimum cable sizes required where the cables are in one of the following conditions: Table 2 1 contains a reference to the appropriate current-carrying capacity table for cables installed unenclosed in air.
Note that these methods result in approximately the same answer.
The factors are also applicable to groups of single-core cables making up parallel circuits in accordance with Clause 3. The ratings apply to conductors having a large number of smaller wires than specified in AS