Cooker Isolator with two 20+ Amp outlets?

[eveares]

Just got my self a Electrolux Built in combi microwave oven that has a connected load of 3000W. It is going along side my existing 3.5KW Electrolux steam oven.

While a 13A BS1362 fuse will just about take this 3000W Load, the manual is ambiguous. On one hand it says;

The cable used to connect the oven to
the electrical supply must comply to the
specifications given below.
For UK use only

Connection via: Cooker Control Circuit

Min. size Cable/flex: 2,5 mm²

Cable/flex type: PVC / PVC twin and earth

Fuse: min: 15 A/max: 20 A

What suggests it has to be wired directly to a 20+ Amp isolator, but then the manual also says.

• Make sure not to cause damage to the mains plug and to the mains cable. Contact the Service or an electrician to change a damaged mains cable.

• Connect the mains plug to the mains socket only at the end of the installation.
  Make sure that there is access to the mains plug after the installation.
  connect the mains plug.

• If the mains socket is loose, do not connect the mains plug.

How should I connect it?

Can you get a twin cooker isolator that has two 20+ Amp outlets? Also is it permitted to connect two single ovens to a single DP isolator?

Regards: Elliott

 

[EFLImpudence]

The rating of the isolator is irrelevant as long as it is more than the current used.
It says you must have a fuse of 15A to 20A.

As you cannot do this easily in Britain I would suggest you connect them both to a dual cooker outlet and replace the Fuse or MCB in the consumer unit with a 20A one.
I am assuming you have a typical cooker circuit.

Both the appliances only come to 26/27A so after diversity the 20A will be fine.

 

[eveares]

By dual cooker outlet, are you referring to a dual cooker isolator or just a normal dual JB/ termination outlet??

I have only ever seen single outlet isolators and cooker isolators with a single socket built in.

At the moment I have the latter with a cheap 800w microwave plunged into the socket.

Was going to replace the 16A MCB for a 20A one anyway as the load with diversity applied will be just over 18 Amps.

 

[Taylortwocities]

 

[deadshort]

Yes, this is one of the electrical accessories that should get a A + for both technical design and retrofitability ! yes i know it's not a word

DS

 

[AndyPRK]

Any idea why it's got a 16a mcb at present ?

 

[Taylortwocities]

The usual reason. It's what came with the CU/what the electrician had in his van!

 

[OwainDIYer]

A + for... retrofitability

It does need quite long L and N wires if being retrofitted.

 

[eveares]

That's the item I thought you meant Taylortwocities. However I am not sure what the exact purpose of that is in my situation when I could just feed both ovens into the output from the Cooker/Socket isolator. I assume your inferring I use two single isolators with it??

Any idea why it's got a 16a mcb at present ?

Good point, never really thought about it before as I trusted my spark at the time who did my extension and never went over the diversity calculations my self. Your right, my single Oven + 5A for the socket comes to around 19.5 Amps with diversity applied.

 

[EFLImpudence]

That's the item I thought you meant Taylortwocities. However I am not sure what the exact purpose of that is in my situation when I could just feed both ovens into the output from the Cooker/Socket isolator.

Can we have a picture of this isolator?

I am thinking this is not a proper cooker circuit which is normally:

30A/32A OPD >> 4mm²/6mm² cable >> cooker switch >> 4mm²/6mm² cable >> cooker connector >>
suitable cable for appliance(s) >> appliances

 

[Taylortwocities]

He probably (and correctly) sized it for just the single steam oven. So a 2.5mm² radial with a 16A MCB would have been adequate for the load at time of installation.
That's assuming it is 2.5mm². How big is the cable csa?

 

[eveares]

Just a normal 45A cooker isolator fed with 2.5mm² T&E cable from the DB. There is also a spare and non terminated unused 2.5mm² T&E cable by the oven what also goes to the DB that was put in as a provision for a second single oven.

Apologies for the poor photo, could not be bothered to take the draw out below the oven what covers and hides the isolator.

Cooker Switch

• eveares
• 28 Aug 2016

 

[EFLImpudence]

Well, as long as the cable supplying that switch is 2.5mm² and does not run through any thermal insulation nor conduit, you could just connect the new oven to the output terminals of the main switch and change the MCB to 20A.

Because the socket is being used as part of the whole demand, there is no need to add 5A to the diversity current.

 

[eveares]

Because the socket is being used as part of the whole demand, there is no need to add 5A to the diversity current

Do you mean not being used, as If I connect new oven to the output terminals of the main switch, the socket would no longer be in use but would still be present.

Think I may just get one of these and two of these.

 

[EFLImpudence]

Because the socket is being used as part of the whole demand, there is no need to add 5A to the diversity current

Do you mean not being used, as If I connect new oven to the output terminals of the main switch, the socket would no longer be in use but would still be present.

No, leave the socket and present oven as it is. Just fit new oven to main switch output