Thread: Switch wire protocol

Originally Posted by Pulse

Mazza, the short circuit current capacity is the reason why we have an MEN system with low fault loop impedance so that fault currents are easily carried to ground and trip the circuit breakers. This will not cause the wires to overheat since that is the purpose the circuit breaker after all.

The real problem is that if someone comes along in the future and thinks, great, 1.5mm2 and installs a 12 or 16A breaker and then installs devices that draw this current through the switch wire then the 1mm2 switch wire is not protected and could catch on fire in normal everyday use.

These are a lot of "ifs" and you won't have troubles as long as the breaker is sized to protect the smallest wire on the circuit, switching or feed, it doen't matter.

Cheers Pulse

No argument here brother, I was trying to keep it simple for him. As you have said the CB is there to protect the smallest cable, however there should not be any cable in the circuit that is smaller than what it starts out as from the CB.

Originally Posted by jackruss

again.

1mm2 cable has a protective device rating of 10A, but can can carry much higher than than before failure.

The way I read the standard, up to 4 times (?? though I take this with a grain of salt).

Anyway as said, the maximum rating for 1.5mm2 is 16amps, and even that thru 1mm2 is not going to melt it.

Now all that said, I apologise for causing this direction in the thread, because on closer examination, it appears to be 1.5mm2 switch wire any way! :eek: . ( whats the difference between 0.69116mm radius and 0.56433 mm radius!)

But I appreciate everyone's concern, without the overly preachy tones!

JR

JR there is no absolute rating for a cable as it just depends on how it is used and in what environment etc.

For example it is possible for a 1mm2 copper cable to carry up to 20a legally in some circumstances and only 5A in others..............it all depends.