Two 16amp ovens on 32amp mcb B supply

[andypo]

Hi,

I am replacing an old double oven with 2 new small ovens. The old oven is wired into a dedicated supply with a switch and the consumer board has a 32amp MCB B breaker.

New oven 1 requires a 15 amp fuse and 2790W. link below.

Series 20 FanCook Integrated Oven Electric Oven | Zanussi

The Series 20 FanCook Oven circulates hot air heat with its fan and ring element. Air is continuously moved around in the oven cavity, to make sure that dishes can be cooked on different level at the same time

www.zanussi.co.uk

New oven 2 requires a 16 amp fuse and 2790W. link below.

Built-in & Integrated Kitchen Appliances | Zanussi

Clever design - the ultimate way to save space! Explore Zanussi's compact built in range of ovens and microwaves for your kitchen.

www.zanussi.co.uk

Can the existing 32amp MCB B supply be repurposed for the 2 new ovens by connecting a 42amp dual connection plate to the existing switch?

Thanks.

 

[SparkyChick]

If the manufacturer recommends 15/16A fuses, I would either (a) downgrade the protective device of the existing circuit and use that, along with install a new circuit for the other or (b) put a small consumer unit like one of the BG garage units on the end of the existing cable and put two 16A breakers/RCBOs in there and supply both from that.

Whilst we can all agree that running a 2.5mm to each device (given we can do that when spurring off a ring) to the ovens will probably not be a problem, if the manufacturers state it should be on a 16A fuse, it's unlikely we could come up with justification for now following their guidance and as such if anything does go bad internally at the very least they have a get out when it comes to honouring warranty terms and if it goes really bad you're on the hook rather than them as you've ignored their guidance.

 

[andypo]

If the manufacturer recommends 15/16A fuses, I would either (a) downgrade the protective device of the existing circuit and use that, along with install a new circuit for the other or (b) put a small consumer unit like one of the BG garage units on the end of the existing cable and put two 16A breakers/RCBOs in there and supply both from that.

Whilst we can all agree that running a 2.5mm to each device (given we can do that when spurring off a ring) to the ovens will probably not be a problem, if the manufacturers state it should be on a 16A fuse, it's unlikely we could come up with justification for now following their guidance and as such if anything does go bad internally at the very least they have a get out when it comes to honouring warranty terms and if it goes really bad you're on the hook rather than them as you've ignored their guidance.

Thanks! I'll go with the BG garage unit on the end of the existing supply. That's my weekend sorted

 

[SparkyChick]

Thanks! I'll go with the BG garage unit on the end of the existing supply. That's my weekend sorted

Just be mindful that technically, you'll be adding a new consumer unit and two new circuits which makes this notifiable works under the building regulations (Approved Document P - You can search for this on-line, 2013 edition is the one that applies to England). As such you should either go through the planning process or employ the services of a member of one of the competent persons schemes who can notify the works on your behalf.

The BG Garage units you can buy off the shelf will typically include an RCD as the main switch along with a 32A and 6A circuit breaker. Depending on whats in the board supplying the existing supply, you may not need the RCD (it's not ideal having two RCDs in series) and the DIY sheds don't stock the board with a main switch.

If you'd like some indication of pricing, drop me a private message and I'll give you and idea of what I'd charge for this (including the building control notification, full documentation for the changes and the associated testing).