micc cable

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hello all

can anybody tell me what amps micc cable can carry clip direct

1.5 2 core

2.5 4 core


thanks
 
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All the info you need is in BS7671. Also depends if you have light or heavy duty MICC.
 
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I've wondered before - why is that? ...
You'd expect HD to have a thicker sheath, possibly more insulation, but an Xmm² conductor is an Xmm² conductor....
Whilst you are obviously right in saying that "an Xmm² conductor is an Xmm² conductor", an Xmm² conductor with a lot more insulation/sheathing will presumably reach a given (e.g. the 'maximum permissible') conductor temperature with less current flowing, as compared with a cable which has thinner insulation/sheathing, won't it?

Kind Regards, John
 
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You can use 1.5 MICC for a ring final circuit.
One can, and either light or heavy duty 1.5mm² MICC has a CCC >20A. Your guess as to why the regs don't allow 1.5mm² Method C T+E for ring final circuits (virtually the same CCC as 2.5mm² Methods 100/102, which is allowed) is as good as mine!

Kind Regards, John
 
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My quess is its more to do with the fact it wont melt or suffer too much from heat damage in the event of that said rating inadvertently being exceeded for some reason or other.
 
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My quess is its more to do with the fact it wont melt or suffer too much from heat damage in the event of that said rating inadvertently being exceeded for some reason or other.
Maybe - but I'm not actually sure that it can necessarily 'tolerate' greater degrees of overload (relative to its CCC, which is already greater than that of corresponding T+E) than can T&E, can it?

Do people sometimes actually wire 20A (light/heavy duty) or 25A (heavy duty) radial circuits with 1.5mm² MICC?

Kind Regards, John ²
 
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Yes. I've used 2L1.5 for both ring circuits and for 20A radial circuits.

You've got to be careful if running MICC at it's max CCC as it may exceed temperaturs safe to touch or mount on normally combustible surfaces.

I guess heavy duty MICC can be run at higher currents as it's increased surface area will dissipate more heat than smaller light duty MICC.
 
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Yes. I've used 2L1.5 for both ring circuits and for 20A radial circuits. ... You've got to be careful if running MICC at it's max CCC as it may exceed temperaturs safe to touch or mount on normally combustible surfaces.
Does that not make one question whether using such a cable at its (alleged) "maximum CCC" is actually 'safe' - hence what "maximum CCC" actually means?
I guess heavy duty MICC can be run at higher currents as it's increased surface area will dissipate more heat than smaller light duty MICC.
Perhaps, but it's not simple. It presumably depends a lot on the thermal properties of the material which has made it larger - after all, in an extreme case, making a cable 'larger' by wrapping it in thermally-insulating material would not increase its CCC (quite the opposite!).

Kind Regards, John
 
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But the filling in MICC is very thermally conductive, so a thicker sheath with more mineral insulation will remove more heat from the conductors.
 

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