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 further information on the effects of ultraviolet radiation it is recommended that the cable manufacturer be consulted.

Guidance is given on the following aspects: Where the enclosed circuits are separated by less than 30008 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.

If possible the actual value should be measured along the cable route as it can greatly affect the current-carrying capacity of the cable.

This cable size represents 30008 minimum size required to satisfy the short-circuit temperature rise requirements. These temperatures will only be obtained in practice if non-adiabatic heating is assumed that is, an appropriate allowance for heat loss into the dielectric during the short circuit is made when calculating the allowable short-circuit current for a given time not longer than 5 s.

Cable short circuit fault current calculator AS/NZS 3008

The selection of the derating factor should be based on the number of circuits that would be loaded; for example, where nine circuits are bunched but only six are loaded at any one time, a derating factor of 0.

The ratings apply to conductors having a large number of smaller wires than ws in AS Click here to sign up. Final Australian edition AS AS imposes limitations on circuit arrangements in order to restrict excessive voltage drop between supply and load.


Enter the email address you signed up with and we’ll email you a reset link. In the preparation of this Standard, reference was made to IEC and acknowledgment is made of the assistance received from that source. Skip to main content. Where other depths of laying apply, the appropriate rating factors shall be as given in Table Tables 2 1 to 2 4 provide a schedule of the installation methods applicable to sheathed and unsheathed elastomer or thermoplastic cables whose current-carrying capacities are given in Tables 3 to In other situations of load power factor the difference between the magnitudes of the supply voltage E and the load voltage V Ass is smaller.

The appropriate rating factors applicable to Tables 3 to 14 are applicable when the current-carrying capacity of flexible cords and cables is determined in accordance with Item a.

The rating factors are based on the assumption that the effective thermal ss of the ground is constant from a depth of 0. Where the type of cable or method of installation is not specifically covered in the tables of this Standard, current-carrying capacities obtained from alternative specifications such as ERA Report may be employed. Three criteria are given for cable selection, as follows: Tables 2 1 to 2 4 give guidance to the appropriate table of current-carrying capacity for different installation methods for the common types of cable insulant covered by Tables 3 to With the same length and disposition of the two cables throughout the circuit, balanced current flow between the parallel cables can be expected.

The higher operating temperature achieved by grouping will not affect the mineral insulation of the unserved cable.

zns Current-carrying capacities are not given in this Standard for polyethylene served or other forms of MIMS cable used for heating purposes, such as trace heating, tank heating or floor warming. The 5-second period quoted is the limit for the temperatures quoted to be valid, not for the application of the adiabatic calculation method.


These conditions have been used to derive the current-carrying capacities tabulated in Section 3. Where values for soil resistivities other than 1. Longitudinal expansion of a cable during a short circuit can be significant and when this expansion is restrained the resultant forces are considerable.

In such cases appropriate rating factors may be obtained from ERA Report Help Center Find new research papers in: Local pressure due to clamping or the use of an installation radius less than 8 times the cable outside diameter, especially for cables that are rigidly restrained, can lead to high deforming forces under short-circuit conditions. Furthermore, a still smaller supply voltage is required to maintain the given load voltage when the current leads the load voltage.

Cable short circuit fault current calculator AS/NZS |

There will be many cable installations where, because of cable selection practices or demand patterns, the current is not sustained at the maximum specified in this Standard. An important aspect concerns the extent and nature of the mechanical restraint imposed on the cable.

For cables not included in this Standard, cable manufacturers should be consulted for recommendations on the current-carrying capacity and acceptable methods of installation.

Suggestions for improvements to Joint Standards, addressed to the head office of either Standards Australia or Standards New Zealand, are welcomed. 30008 number of worked examples on cable selection are included in Appendix A.