Design Current and Calculation of the Minimum Required Value of the Cable's Current Carrying Capacity



General



For ring socket circuit with Ιn = 30Α or 32Α



Ring socket circuits otherwise


Grouped circuits not liable to
simultaneous overload



General motor circuits


Star-Delta Motor Circuits



With:


the design current of the circuit under consideration in Amperes

the nominal current or current setting of the protective device protecting the circuit against overcurrent  in Amperes

the minimum required value of the cable’s current carrying capacity


Busbar Trunking System notes: With protection using a gG (gI) fuse an additional correction factor,  equal to 1.1, is used. Note that using gI fuses for protection means reducing the busbar trunking’s allowable current.



Checks



With:

the design current of the circuit under consideration in Amperes

the nominal current or current setting of the protective device protecting the circuit against overcurrent  in Amperes


the minimum required value of the cable’s current carrying capacity

the value of current tabulated in cable tables

Correction factor for ambient temperature

Correction factor for thermal insulation

Correction factor for grouping

Correction factor for using BS3036

Correction factor for ground installations

Correction factor for underground installation depth

Correction factor for ground soil thermal resistivity

Correction factor for triple harmonic currents

Motor starter overload. By default