Fuses made from copper strip

Looking through my bits box for a few fuses and holders for a 40 Kw alterna tor I use for 3 phase in my workshop, I was looking for some over 50 amps i n case anything went wrong with any of my machines. I found 3 which look ab out right but they are just a strip of copper 2 and a quarter inches long a nd half an inch wide clamped into a suitable holder. As a guess I would say they would probably blow at a bit over 50 amps. The thickness is, as far a s I can measure it on my caliper is 1/32nd of an inch

Does any clever chap know how I can calculate the current capacity from the se measurements and so adjust it by cutting the strip in half, for example.

These 3 phases will be for fusing 3 separate 13 sockets but if I just put t hem in the lines they will also protect the outlet on 3 phase devices too.

I suppose I could just hook an ammeter in line and a heavy duty variac, whi ch I have and just wind it up till it blows, but I do not have an unlimited supply of the copper strips and it is not very scientific, is it?

Anyone got a clue? Thanks George.

Reply to
George
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Are the holders enclosed? sounds like a sizeable amount of copper to spray around if it goes pop ...

As a starter, this calculator

reckons you need 0.42 mm^2 of copper for a 50A fuse, which sounds small to me, but would make your strip over 20x the required CSA.

Another site seems to give same ball-park sizes, so maybe it's not to small

Reply to
Andy Burns

50 amp fuse wire is 21 guage or.721mm dia or .412 sq mm the copper you have would be hundreds of amps.
Reply to
F Murtz

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