Section 1 General Rules

The choice of electrical apparatus and conductors according to the conditions of a short circuit. The choice of conductors according to the conditions of heating in case of a short circuit

Encyclopedia of radio electronics and electrical engineering / Rules for the installation of electrical installations (PUE)

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1.4.16. The heating temperature of conductors during a short circuit should not exceed the following maximum permissible values, º C:

1.4.17. Checking cables for heating by short-circuit currents, in cases where this is required in accordance with 1.4.2 and 1.4.3, should be carried out for:

1) single cables of the same construction length, based on the short circuit at the beginning of the cable;

2) single cables with stepped sections along the length, based on the short circuit at the beginning of each section of the new section;

3) a bundle of two or more cables connected in parallel, based on the short circuit directly behind the bundle (according to the through short circuit current).

1.4.18. When checking for thermal resistance of devices and conductors of lines equipped with high-speed automatic reclosure devices, an increase in heating due to an increase in the total duration of the short-circuit current through such lines should be taken into account.

Split wires of overhead lines when checking for heating under short-circuit conditions are considered as one wire with a total cross section.

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