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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For the purpose of determining the maximum voltage drop value in Clause 4. Where a neutral conductor is required to be substantially loaded it shall be placed adjacent to the associated active conductors and the clearance measured as appropriate see Note 3 for lightly loaded or unloaded conductors.
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 temperature correction factor from Table Where a number of installation conditions exist along a cable run or variations to the specific conditions occur, reference shall be made to Clauses 3.
For other conditions, see Clause 3. This Standard was issued in draft form for comment as DR Where cables are buried directly in the ground, or bzs be nxs by frequent fixing, then provision should be made to accommodate the resulting longitudinal forces on terminations and joint boxes.
Suggestions for improvements to Joint Standards, addressed to the head office of either Standards Australia or Standards New Zealand, are welcomed.
The impedance of cables is usually expressed in units of ohms per metre or ohms per kilometre, which enables the total impedance for any given cable length to be readily calculated.
Cables wit h minimum spacings in air as Tables 9 and 10 shown and installed — Two-core see Note 5 a spaced fr om a wall or vert ical surface; 9 cables Columns 2 and 3 b supported on ladders, racks, perf orated or unperf orated trays, cleats or hangers; c in a switchboard or similar enclosure; jzs or Tables 12 and 13 10 Three-core see Note 5 cables Columns 2 and 3 d suspended fr nz a catenary or as a self – 11 supported overhead cable.
Fixings should be spaced sufficiently far nzz to permit lateral movement of multi-core cables or groups of single-core cables.
The time taken to reach this steady state temperature will vary depending on the type of cable and installation conditions.
Some situations where this will occur are as follows: Guidance is given on the following aspects: Bzs values of V c are obtained from Table 42 for copper and Table 45 for aluminium and result in the following maximum route lengths: Furthermore, a still smaller supply voltage is required to maintain the given load voltage when the current leads the load voltage. The ratings apply to conductors having a large number of smaller wires than nzz in AS Limitations of materials in contact with these metals should also be considered.
Similarly, lower ambient temperatures may apply for cables installed in concrete slabs on or above the surface of the ground. Permission may be conditional on an appropriate royalty payment.
Cable short circuit fault current calculator AS/NZS 3008
Where the enclosed circuits are separated by less than 2 m, the appropriate derating factor shall be as given in Table 26 or, for installation methods not covered in this Standard, alternative specifications as recommended in Clause 1.
An important aspect concerns the extent and nature of the mechanical restraint imposed on the cable. Note that these methods result in approximately the same answer. Therefore the voltage drop on a single-phase basis will only be that associated with the current flowing in one active conductor, i.
No restriction is placed on the number of circuits that may be arranged horizontally with the spacings given; however, care should be taken if more than three circuits are arranged vertically and full cable utilization is required. The current-carrying capacity values in the tables are based upon typical installation conditions and a range of different materials as described in Clause 3.
The number and date of the Standard should therefore be clearly identified. The actual derating factor in this situation may be closer to 0.
Cable short circuit fault current calculator AS/NZS |
Ae 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. From the derating factors of Table 25 1 for groups of single-core cables buried direct, it can be shown that three trefoil groups of single-core cables, each group representing a circuit of mm 2 conductors and spaced apart, as illustrated, are required.
30008 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.
The objective of the Standard is to specify current-carrying capacity, voltage drop and short-circuit temperature rise of cables, to provide a method of selection for those types of electric cables and methods of installation which are in common use at working voltages up to and including 0.
The derating factors have been determined from the hottest cable in the group and assume that all cables are of the same thermal grade of insulation. Higher current-carrying capacities are obtained in clay or peat soils which may have resistivities as low as 0.
It is important therefore that Standards users ensure that they are in possession of the latest edition, and any amendments thereto. The higher operating temperature achieved by grouping will not affect the mineral insulation of hzs unserved cable.
Part 2 will deal with cables for use with alternating voltages over 1 kV. Statements expressed in mandatory terms in notes to tables and figures are deemed to be requirements of this Standard. These temperatures are for materials where there is no electrical or other requirements necessary, i.
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