Do I need a new cable/mcb for my new cooker? I hadn’t considered this when I bought it!
The cooker seems to be rated as 12.8 kw (at least, that number with no other explanation is on a sticky label on the back of the machine, along with a second label saying main oven alone 2.7 kw). The cooker manual gives the 4 hotplates as 1.2kw, 2.2kw, 2.2kw, 1.8kw (7.4kw in total), but oven power is only given as 0.66 and 0.74 kw/h. The manufacturer’s helpdesk is less than forthcoming about the fuse size needed, but say they used to specify 45A, but now leave it to the installer to decide.
The cooker is essentially a like for like replacement of an older cooker (4-rings, oven and grill). The cooker outlet is supplied by a 6mm cable from 32A mcb on an MEM consumer unit (house built c1990, mcb probably 321 QEB, not checked). The cable is about 6m long, and runs alone through ceiling joists and down behind dry lining (not in conduit) to the cooker unit (without socket).
So my specific questions are:
1. Assuming the second oven/grill is also 2.7 kw, the total maximum cooker load is indeed 12.8 kw (rings 7.4ks, ovens 5.4kw) – or 56A . However, as I understand it, allowing for diversity could cut this to 10 +0.3*46 = 23.8A . So would the existing 32A fuse and cable combination would be OK?
2. Surely, just doing a like for like replacement would be safe, even if the mcb were to trip, the cable would be protected.
3. Given the cable length and fixings, its allowable current could be increased to 47A, so would it be OK to change the mcb to 40 or even 45A?
4. Upgrading to a 10mm cable and 45A mcb would be quite disruptive, and presumably a new consumer unit would be recommended. Is all this really necessary just to replace my cooker?
Any advice would be much appreciated
The cooker seems to be rated as 12.8 kw (at least, that number with no other explanation is on a sticky label on the back of the machine, along with a second label saying main oven alone 2.7 kw). The cooker manual gives the 4 hotplates as 1.2kw, 2.2kw, 2.2kw, 1.8kw (7.4kw in total), but oven power is only given as 0.66 and 0.74 kw/h. The manufacturer’s helpdesk is less than forthcoming about the fuse size needed, but say they used to specify 45A, but now leave it to the installer to decide.
The cooker is essentially a like for like replacement of an older cooker (4-rings, oven and grill). The cooker outlet is supplied by a 6mm cable from 32A mcb on an MEM consumer unit (house built c1990, mcb probably 321 QEB, not checked). The cable is about 6m long, and runs alone through ceiling joists and down behind dry lining (not in conduit) to the cooker unit (without socket).
So my specific questions are:
1. Assuming the second oven/grill is also 2.7 kw, the total maximum cooker load is indeed 12.8 kw (rings 7.4ks, ovens 5.4kw) – or 56A . However, as I understand it, allowing for diversity could cut this to 10 +0.3*46 = 23.8A . So would the existing 32A fuse and cable combination would be OK?
2. Surely, just doing a like for like replacement would be safe, even if the mcb were to trip, the cable would be protected.
3. Given the cable length and fixings, its allowable current could be increased to 47A, so would it be OK to change the mcb to 40 or even 45A?
4. Upgrading to a 10mm cable and 45A mcb would be quite disruptive, and presumably a new consumer unit would be recommended. Is all this really necessary just to replace my cooker?
Any advice would be much appreciated