Is 4sqmm being phased out (can't see it on Screwfix) - if so, does that mean that you will have to use 6sqmm when you would previously have used 4?
I posted earlier in the thread : Subject: Electric Double Oven Supply snipped-for-privacy@4ax.com but no responses yet
- surely some of the connectors (eg cooker) which would previously take 2 * 4sqmm cables will not take not 2 * 6sqmm?
double-oven and calculated its peak AC current. You mentioned 30A. Try QVS for discount cable, still both 4mm2 and 6mm2 T&E available, either sold per metre or per reel.
2.5mm2 handles 19A max and is for ring main/spur power wiring only.
...and where do you obtain that rating from? or is it in insulation and protected by a 3036 and grouped with loads of other cables in a boiler house?
No - but it is perhaps less commonly required than other sizes, so might not be stocked by outlets that only want to handle fast-moving high-volume lines.
The terminal capacity of the MK K5045 cooker connection unit is given as
2 x 10 mm^2 (including the input wiring), so 3 x 6 mm^2 ought to fit. In any case these units aren't really intended to feed more than one output cable. If there are two appliances to connect, use two connection units side-by-side. Of course that doesn't help with overall terminal capacity if you loop the input from one to the other, but it will if you feed them separately from the control switch (provided that has sufficient capacity...).It's out-of-date information: the as-installed cable rating for a ring circuit has to be at least 20 A, and might need to be larger if known heavy loads are concentrated toward one end of the ring (e.g. where all the kitchen loads are connected near one end).
Up-to-date ratings for PVC twin-and-earth cables are as follows:
[From BS 7671 Table 4D5A]Size Ratings in amps (ambient temperature 30 deg.C mm^2 A B C conductor temperature 70 deg.C)
---- ---- -- --
1 11.5 12 16 1.5 14.5 15 20 2.5 20 21 27 4 26 27 37 6 32 35 47 10 44 47 64 16 57 63 85Key to columns: A - in conduit in insulated wall (ref. method 6) B - directly in insulated wall (ref. method 15) C - clipped direct (ref. method 1)
All the usual derating factors apply.
Many thanks
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