possible to spur of this and im guessing u would have to spur off using 4mm cable, is there a limit on spurs? can u spur 2 sockets in series off a socket.
30 amp rewirable fuse feeding radial with 4mm cable
- Thread starter lee1982
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There's no such thing as a spur from a radial circuit, so yes, as long as you stick with 4mmsq (or other appropriately sized conductors for volt drop etc) then it's no problem to come off the radial to as many sockets as you like.
I should point out, though, that this isn't a series connection, as that would be a single conductor running into live of one socket, out of neutral and then into live on the next socket, out of neutral to the next socket, and so on. We don't wire things this way for (hopefully) obvious reasons.
I should point out, though, that this isn't a series connection, as that would be a single conductor running into live of one socket, out of neutral and then into live on the next socket, out of neutral to the next socket, and so on. We don't wire things this way for (hopefully) obvious reasons.
ty, sorry bad terminology on my part, spur of a spur i should have said
Fair enough. Still, as a radial circuit with 13A sockets is just a succession of spurs from spurs, it really isn't a problem.
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No, but 4mm² on a 30A rewirable is...
why's that then BAS?
the picture in the back of the book say's it's fine..
the picture in the back of the book say's it's fine..
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I have questioned the use of 4mm cable on 32A radials many times as although clipped direct it has a ratting above 32A buried in a wall it does not. And although you may get two 6mm cables in some MK Logic state
So 45 x 0.725 = 32.625 so no reason why Ali-tube 4mm cable clipped direct should not be used on a 32A fuse on a radial circuit. So nothing wrong with the BS 7671:2008, Corrigendum (July 2008) diagram although using 70 deg C twin and earth is another story.
Many other makes you will find you can't get two 6mm cables to fit. Because most of the Ali-tube cable to BS 8436 is rated at 90 deg C not 70 deg C it does have a higher rating and I was surprised to see Table 4D5 does not have an equivalent for Ali-tube which since Ali-tube is made special for stud walls one would have expected it to have been included.
So 45 x 0.725 = 32.625 so no reason why Ali-tube 4mm cable clipped direct should not be used on a 32A fuse on a radial circuit. So nothing wrong with the BS 7671:2008, Corrigendum (July 2008) diagram although using 70 deg C twin and earth is another story.
And it does not have a rating of (30 ÷ 0.725) for any installation method.
I'm not surprised - 4D5 is for BS6004 flat cable.
You need 4D2 for BS8436.
See the warning note on any of the tables that have ratings for 90° cables - terminating them in accessories only rated for 70° is also another story.
There is such a thing as a spur from a radial
When you use a 2.5mm cable to branch off a 4mm radial it is called a spur.
I am NOT suggesting the OP do this.
It depends on the thermal resistivity of the wall - method number 57 which is buried direct in masonary with a thermal resistivity not greater than 2K.m/W refers you back to method C which is the one for clipped direct, as does method number 58 which is the same as above but with added mech protection.
I assume a 20A fuse would be fine for 4mm ?
20 ÷ 0.725 = _____
CCC for 4mm² lies between _____ & _____ assuming no other correction factors apply.
CCC for 4mm² lies between _____ & _____ assuming no other correction factors apply.
It depends.
thought you could only get fusewire in 5, 15 and 30?
Wylex do a 20A rewirable carrier. 20A fusewire does seem to be availible though TLC at least only sell it by the reel http://www.tlc-direct.co.uk/Products/TLFW20.html .
Moving to a 30A cartridge fuse or 32A plug in MCB may be a better option though (assuming it's a wylex standard board)
Moving to a 30A cartridge fuse or 32A plug in MCB may be a better option though (assuming it's a wylex standard board)
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