The modern way is a flat braid and a constant force spring, as hot works are now considered dangerous. If it needs replacing its really a call to the DNO.

But the Adiabatic eqn., well lets assume we start at 30c and the lead tin solder is soft solder and melts at 200c

(235 is a good no to remember, both for uranium (atomic mass) and for most solders being soft, including the higher lead fraction ones, and the modern lead free stuff. we had a tech who used to set all the soldering tools for what he called a "uranium run" when we switched to lead free in the mid 2000s.)

where the '2' denotes a square

I2t<=K2S2

S is the minimum protective conductor cross-sectional area (mm2)

I is the fault current (A)

t is the opening time of the protective device (s) now that is tricky - the curves go to 0.1 sec normally, and then it is "see maker's data"

page 26

here suggests 900A and 0.01 seconds for a 60A fuse.

if it got no faster, so 0.01s* 1800A*1800A

k is a factor depending on the conductor material and insulation, and the initial and maximum insulation temperatures. take k= 160

for 30 to 200C

page 26

here suggests 900A and 0.01 seconds for a 60A fuse.

if it got no faster, so 0.01s* 1800A*1800A, so I2t is 32400 amps squared per second.

So S= root of that divided by k 2

32400 /(160*160) = 1.22 mm2, so S= 1.125mm.

But really you need more info, if anyone on the substation has PME, as there may be unfused and therefore very long duration currents between plumbing and the CPC, that are not coming via your company fuse over which you have little control.These diverted neutral currents can overheat inadequate earthing arrangements.

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regards Mike