On Sat, 18 Mar 2017 04:18:04 -0700 (PDT), wrote:

On Saturday, 18 March 2017 00:07:59 UTC, James Wilkinson Sword wrote:
Despite extensive googling, there seems to be nothing that tells me how much
current flows along wires on a national grid pylon. They only list voltages.
Anybody know?

A 400 kV National Grid circuit may carry 1 kA in each of its three phases, thus transmitting a power of 700 MW.
A 132 kV distribution circuit may carry 300 A in each of its three phases, thus transmitting a power of 70 MW.
An 11 kV distribution circuit may carry 150 A in each of its three phases, thus transmitting a power of 3 MW.
A 400 V final distribution circuit may carry 200 A in each of its three phases, thus transmitting a power of 150 kW.

(Remember, these voltages are phase-to-phase voltages, the phase-to-earth voltages are 1.73 times lower. Thus (400 kV/1.73) x 1kA x 3 = 700 MW.)

http://www.emfs.info/what/terminology/ (site maintained by National Grid)

[Pylon type] L12 is effectively the L6 replacement will take twin conductors up to 850mm2, but all aluminium conductor rather than the heavier steel cored kind formerly used.

http://www.gorge.org/pylons/structure.shtml

Someone is being slightly economical with the truth at the emfs.info site. There
are 400kV overhead circuits in the UK rated at around 3600MVA short term post
fault so that equates to around 5000A.

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