2 Ovens on Cooker Circuit

[dal5band]

I need to wire two ovens onto an existing 32AMP cooker circuit. The hob is gas. One oven is a combi and comes in under 13Amp with a plug, so will go on a single socket.
The problem is the other oven is maxed at 15amp so exceeds the normal fused spur capacity. Is there such a thing as a 15 or 20amp fused spur unit ? The alternate is to connect via a 20amp DP switch but them the oven flex is only protected by a 32amp breaker.

Any ideas ?

 

[Taylortwocities]

OK

32A cooker circuit must terminate in an isolation switch. A 45A one is usual. This should be within 2 metres of the oven(s).

The output of the switch is 6mm cable to a flush metal back box.

To the back box you fit a dual appliance plate

From this, one 6mm cable to a 13A socket for your >13A oven.
A second 6mm cable direct to the larger oven.

Thats it.

 

[dal5band]

OK should be able to do that - on closer inspection, have discovered the cooker switch box has a blank cover, but inside is a big connection block which carries the connections down to a socket under the units - currently just for the hob ignition. So Install a cooker switch which will be the isolater for the two ovens and then as you say split it below.

Thanks

 

[Taylortwocities]

Sounds like thats a plan then.

 

[OwainDIYer]

If the manufacturer's instructions state the oven must be fused at 15A, 16A or 20A then they must be followed.

It's a common problem with appliances intended for European 16A/20A radial circuits.

 

[dal5band]

yes , the oven is only just over the 13 amp fused spur limit which is why I asked the original question. Perhaps we need a higher rating fused spur in the UK ?

 

[Taylortwocities]

Perhaps we need a higher rating fused spur in the UK ?

That is not ever going to happen. The UK is gradually moving away from ring final to radial circuits in any case, so the problem then disappears.

But, in any case, you have a serviceable 32 amp radial circuit that you can use.
The only question is: what do the manufacturer's instructions say about the size of protective fuse for the larger oven?

 

[JohnW2]

The only question is: what do the manufacturer's instructions say about the size of protective fuse for the larger oven?

If that did prove to be an issue, the OP could presumably feed that larger oven via a 16A MCB in a suitable enclosure?

Kind Regards, John

 

[Taylortwocities]

In theory, yes.
But not really practical in his kitchen.
Where would he put the 16A MCB?. The cable exit is behind the cooker.

 

[JohnW2]

In theory, yes.
But not really practical in his kitchen. Where would he put the 16A MCB?. The cable exit is behind the cooker.

The protective device (fuse in plug) for the smaller over is also presumably behind the oven, so if (I realise that might be a big if) there were space there for an enclosure to house the MCB, it would be no less accessible than the OPD for the other oven.

Kind Regards, John

 

[dal5band]

Just to et your minds at rest ... Both ovens will be contolled by the DP 45amp cooker switch adjacent to the tall housing unit. The splitting occurs either behind the unit (no back) or underneath, plenty of room below behind the kick board which is removable.
Plenty of options.

 

[JohnW2]

Just to et your minds at rest ... Both ovens will be contolled by the DP 45amp cooker switch adjacent to the tall housing unit. The splitting occurs either behind the unit (no back) or underneath, plenty of room below behind the kick board which is removable. Plenty of options.

Fair enough. However, as TTC said, and as you presumably understand, the question is whether the manufacturer of the larger oven requires that it be protected by a 15A/16A (or maybe 20A) fuse/MCB. If it does require such protection, then you would have to find space for a 16A or 20A MCB, in an enclosure, since you cannot have a fuse >13A in a fused connection unit.

Kind Regards, John

 

[OwainDIYer]

Fair enough. However, as TTC said, and as you presumably understand, the question is whether the manufacturer of the larger oven requires that it be protected by a 15A/16A (or maybe 20A) fuse/MCB. If it does require such protection, then you would have to find space for a 16A or 20A MCB, in an enclosure, since you cannot have a fuse >13A in a fused connection unit.

I think there's a market for an accessories manufacturer to make a cooker control unit in a double faceplate with 2 x 20A DP MCBs and separate output terminals, and common input terminals for a 30/40A cooker circuit.

 

[JohnW2]

I think there's a market for an accessories manufacturer to make a cooker control unit in a double faceplate with 2 x 20A DP MCBs and separate output terminals, and common input terminals for a 30/40A cooker circuit.

Functionally-speaking, I'm inclined to agree. In practical terms, if standard CU-type MCBs were used, and mounted the usual way around, it would be a very deep accessory (and presumably would also have to have a front cover sticking out, too. If the MCB(s) were mounted 'sideways' (lever to left or right), they could go in a pretty shallow surface-mounted accessory, but I've never seen them used that way.

Someone is bound to point out that the 'proper' way to do it is to have separate radials going back to separate 16A MCBs at the CU - and I suppose that 2 x 2.5mm cables is not much more copper than 1 x 4mm² (in fact, given a favourable installation method, one might even get away with 2 x 1.5mm², and actually save some copper!).

Kind Regards, John

 

[EFLImpudence]

If the manufacturer's instructions state the oven must be fused at 15A, 16A or 20A then they must be followed

But do they state fuse (opd) requirement in all cases?

Don't ovens/hobs which are supplied without a flex merely state the required supply?
The opd will then depend on the cable

Ovens/hobs supplied with a flex will state the fuse size which will apply to both the supply needed and flex rating.