>=20
> In those circumstances, I'd expect a current of 160 A to trip a 16
> A
> breaker within one cycle, 20 ms at 50 Hz.
>=20
> I don't even know how to design a breaker _not_ to trip at 160 A.
>=20

All circuit breakers have a maximum breaking capacity rated in=20
Amperes. Above this value the fuse is not guaranteed to break at a=20
short circuit condition. It is important that the breaker can handle=20
the prospective short circuit current at the supply terminals. The=20
prospective short circuit current is depending on the size of the=20
breakers in the wiring before this one, their breaking=20
characteristics and minimum impedances in the wiring to the breaker.

Another thing to watch out for is very long wires before the last=20
breaker which will have a significant impedance which in turn will=20
limit the short circuit current so much that the breaking time may=20
become so long that the resulting heat in the wires could damage the=20
insulation or even start a fire.

There are software that will give you an ok/nok for all given=20
parameters and components of a circuit. Sometimes you can just input=20
the wire length, the wire gauge/area, intallation method and the make=20
and model of included breakers.

Other important fuse parameters are overvoltage category and=20
pollution degree, which have to match the installation site.

It is also quite difficult to compare a UL approved fuse with an=20
IEC/EN approved fuse because ratings and characteristics are=20
determined under different conditions.

Also note that maximum amperage for a wire with a given gauge/area is=20
depending on its installation method in the building (how many wires=20
bundled together, distance between wires, single conductor wire or=20
multiple conductor cable, embedded in wall, insulation material...).

All this is the reason you have to pay a certified electrician to do=20
the wiring in your home.

/Ruben



--=20
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