That is a different subject.
That is a different subject.
Absolutely correct. That needs to be taken into consideration along with the length of the cable.No its not.
As the designer / installer its a very sensible precaution .................
Not installing a product in line with manufacturer instructions would make it void from any warranty as well. But no way 6mm cable is fine for 10kw.That is not correct.
A lot of flats have 10mm² as their supply cable for everything.
There are many running (incorrectly) on 4mm² and a 32A OCPD but all of that is wrong and I hope due to the incompetence of DIYers.I think the only nonsense was from yourself stating 6mm is fine for a 10.5kw shower??!
You've not seen a 10.5kw shower?! Don't know where you have been then...
The cable is sized on the MCB rating, not the load.The "10.5 kW" will, almost inevitably, relate to 240V, hence about 41.9A at 230V (the nominal voltage we uses for design calculations)?
The CCC of Method 6mm² cable is 47A
What's your problem with that? 41.9 is definitely less than 47.
Even if it were10.5 kW at 230V (and I've never sen a shower like that), the current would still only be about 45.7A - so, again,Method C 6mm² would be OK. - again, 45.7 is less than 47.
It certainly is. So is 4mm² (Method C CCC = 37A).
(if, as usual, it's 7.5kW at 240V, that's about 29.9A at 230V; if {very unusually} it's 7.5 kW at 230V, that's 32.60) - both 29,9 and 32.6 are less than 37.
What is that nonsense? What has 'length of run' got to do with the MCB rating?
If you're going to offer information or advice, it really ought to be correct!
Kind Regards, John
Such as the spur on a 32A ring? We've also had regular comments stating the situation is different for heating elements as they cannot cause an overload (some of us appreciate they can )The cable is sized on the MCB rating, not the load.
I don't get this. For sockets we have given designs.Such as the spur on a 32A ring? We've also had regular comments stating the situation is different for heating elements as they cannot cause an overload (some of us appreciate they can )
Indeed so, but what I've been responding to is the assertion that 6mm² cable would be inadequate "for a '10.5 kW' shower" (without any mention of the MCB rating) - but, as you say, it's also necessary that the (unmentioned) MCB rating is no greater than the CCC of the cable.The cable is sized on the MCB rating, not the load.
You don't get that it is permitted to use a cable rated at 20A on a 32A ring or radial circuit?I don't get this. For sockets we have given designs.
The formula for the tabulated current carrying capacity is
It = In / ( Ca Cg Ci Cf )
Indeed so, but what I've been responding to is the assertion that 6mm² cable would be inadequate "for a '10.5 kW' shower" (without any mention of the MCB rating) - but, as you say, it's also necessary that the (unmentioned) MCB rating is no greater than the CCC of the cable.
Kind Regards, John
... We've also had regular comments stating the situation is different for heating elements as they cannot cause an overload (some of us appreciate they can )
It is sometimes 'used' or done when a 45A MCB is not available (for make of CU?) and 50A is therefore (allowed to be) used.I can't think of any particularly good reason why that argument cannot be used in relation to a circuit (hence cable) supplying (only) an electric shower, but I have to say that I don;'t recall having seen the argument used in that context.
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