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Size of DNO main

Kelly Marie Angel

If you have a 3 phase main cable protected by 400 amp fuses what size is the cross section area of each core? Also what would be the size of a single phase take off  from this if its protected by a 100 amp fuse at the load end? As you mite of guessed I'm talking DNO cables 

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    Varies a bit on old existing infrastructure. But 240mm is widely used, sometimes copper and sometimes aluminium. Some DNOs use copper from the substation to the first joint, and then aluminium thereafter. Copper gives a greater margin for de-rating when a number of cables are grouped together near the substation. Aluminium is cheaper.

    Service cables also vary a bit, but 25mm copper or 35mm aluminium are often used. Sometimes one size up if the service cable is longer than the norm.

    Both street mains and service cables are constrained by voltage drop rather than by current carrying capacity.

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    Varies a bit on old existing infrastructure. But 240mm is widely used, sometimes copper and sometimes aluminium. Some DNOs use copper from the substation to the first joint, and then aluminium thereafter. Copper gives a greater margin for de-rating when a number of cables are grouped together near the substation. Aluminium is cheaper.

    Service cables also vary a bit, but 25mm copper or 35mm aluminium are often used. Sometimes one size up if the service cable is longer than the norm.

    Both street mains and service cables are constrained by voltage drop rather than by current carrying capacity.

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