Electric Double Oven and Hob Wiring / New Fuse Box ?

[kingfisher]

I am installing a new kitchen which previously had a gas cooker and hob. The new kitchen is being delivered with an electric hob (5.8kw) and electric double oven (5.5kw). Better half has decided these are in seperate parts of the kitchen. According to my calculations both devices will draw about 25A each or thereabouts. I believe the worse case current load for a 6mm cable (inside wall) is 32A, so :-

1. Am I in the clear if a run a 6mm cable connected to a 30A fuse dedicated for each device ?

The big problem is that my 1970's house has an old Wylex fuse board with no 6mm cables in sight. It has two 5A fuses for upstaires and downstairs lighting, one 15A for ALL 13A sockets, one 30A fuse (which did go to hot water cylinder but now just used for combi boiler powering) and one (smaller) 45A fuse which goes to know not where (doesn't test to any socket in kitchen.....probably not used). I think the latter fuse is connected to a 2.5mm cable.

2. Do I need a new fuse box or MCB or can I frig current one (not decided if to employ electrician yet).

Any comments very welcome.

2.

 

[stardelta]

sounds like your wiring is very old,as is your fuse box,you said you had a 45amp fuse feeding a 2.5mm cable find where that is going straight away,possible risk with that.....as for appliances each would have to have thier own circuit and isolation but as for connecting these to your existing unit i would not, if i were you i would call in an electrician to check your fuse unit for the new loading these appliances will put on it,and check your other circuits wich sound rather dated you are obviously spending a few bob on the kitchen don`t skimp on the wiring.....

 

[Steve]

both those appliances need a 30A radial. Can you post a picture of the fuse box? does it have a maximum load printed on it? Chances are, its 60A (though we did have a wylex rated at 100A), and i would recommend you get a new fuse box before loading all this onto it.

Did the property have an electric shower at some point?

 

[kingfisher]

I was incorrect to say the 45 Amp fuse had a 2.5mm cable....it just looked like it. After tracing this wire through I found it was 6mm and went to the old cooker socket in the kitchen, which of course makes perfect sense. Anyway, this cable went to the wall between the old kitchen and the dining room (the wall has now been removed) so the cable has been cut and is no longer in circuit (to difficult and to short to re-route).

All in all, after reading much including comments on this forum, I believe I am capable of doing the general kitchen electrics. But I still have this issue with the fuse box.

I have run a dedicated 6mm cable from the hob area to the fuse box area and the same from the oven area to the fuse box area. The old Wylex fuse box measures 9 inches by 7 inches. There are no markings (ratings) anywhere.

Question is - do I need a new unit or can the two 6mm cables by run into the one available fuse which the original 6mm cable went into? If the latter, maybe I dont need an electrician to do this ?

p.s could not work out how to paste an image here, so I provide a URL instead (you might have to copy and paste into browser).

http://www.kingfisher-apartments.co.uk/fuse_box/fuse-box-wylex.jpg

[/url]

 

[Adam_151]

The cable that goes to the base for the 45A BS1361 does indeed look very much like 2.5mm² are you sure about it being 6mm² ?(not to mention that 6mm² on a 45A fuse is pushing things anyway) anyway, if its not used anymore, you may as well disconnect it from the CU and get rid of it (that way no one is tempted to stick a fuse in the empty carrier and blast the plaster off where cut ends have been buried)

Anyway, it looks like your CU is due for replacement tbh, it would be a wise move to start getting quotes to replace it with a much more modern unit (and make sure you have free capacity even after adding the cooker circuits)

 

[JohnD]

Your CU is very old, and contains rewirable fuses too, which are rather undesirable. I have an idea that the old Wylexes of that size had a 65 amp main switch, which will not be enough. The bigger 12-ways had a 100a. BTW I think you are mistaken about the (blue) 15A and the (red) 30A. The 15A has only one cable going to it, and is typical of an Immersion heater. The 30A has two cables, which is typical of a ring main for sockets. (though by modern standads one ring main for the whole house is very parsimonious)

Certainly get a nice new CU professionally fitted, to supply the kitchen circuits at least. You may think about having a new ring for the kitchen at the same time, as the kitchen appliances benefit from plenty of sockets, and the load can be high if you keep the washing machine and tumble drier in there as well as the usual kettle, toaster, microwave and dishwasher.

If you are hesitant about the cost of having the rest of the house circuits renewed at the same time, get a biggish CU installed with the unused ways blanked of, but with room for a later split-load RCD and plenty more circuits.

 

[ban-all-sheds]

All in all, after reading much including comments on this forum, I believe I am capable of doing the general kitchen electrics.

Are you aware of/do you care about Part P?

If you do plan a new CU, here's my recent 2p worth on things to think about:

//www.diynot.com/forums/viewtopic.php?p=286100#286100

 

[JohnD]

IIRC, Ban recommends 80 double sockets in a kitchen though I'd say, at least one per metre of worktop length, and personally, I'd add a 20A DP switch with neon every 60cm of worktop to feed a 13A socket for a future appliance below. That way you can put fridges and things wherever you want.

 

[ban-all-sheds]

IIRC, Ban recommends 80 double sockets in a kitchen

 

[Steve]

ah, your kitchen projects coming along ban! youve mounted the cupboards now! Do keep posting updates!

 

[Qedelec]

Ahem! those cupboards are upside down, correction, they are the Australian ones.

 

[Steve]

actually, ban, i think you forgot the carcases, just mounted the doors on the wall. Dont think mrs sheds will appreciate that somehow.

 

[JohnD]

Just to ckeck, you do have the plastic cover screwed to the front of that unit, don't you? It surely isn't normally exposed like that?

I was a bit puzzled by the green fuse carrier on the right, I don't remember seeing one mounted there before.