Replacing 13A flex outlet with 16A

[hba]

Hi, I'm replacing a microwave oven rated at 13A with one rated at 16A. This plus a conventional oven are fed from a 32A MCB in a consumer unit, via a single 6mm2 T&E cable to two 13A fused flex outlet switches. The original installation was professionally done seven years ago. Can I replace one of the fused switches with e.g. a 20A flex outlet switch to provide the 16A supply? Many thanks in advance.

 

[Midwest]

I suppose the first question that needs asking, is what are the manufacturers instruction on the supply for the new microwave? Does in mention how it should be connected to a supply & fuse rating?

 

[hba]

Thanks. It's 3.65 kW, 16A according to the spec. Comes with 150mm of "electrical supply cord" so needs a flex outlet connection.

 

[Midwest]

Hmmm, I'm in two minds about this. A previous install I did, a new supply was required for combo microwave due to its location, so it was easy to follow manufacturers instructions, and provide 16A mcb etc.

I'm led to believe these have typically, a 900W microwave and 2.5-3kW standard element. Supplying a standard oven from a 32A supply, would normally be no issue, as is fixed load and manufacturer's supplied lead would be designed for its max load. But manufacturer does state 16A fuse?

 

[hba]

It specifies 16A current, not that it should have a 16A fuse. But I don't have it yet so no installation guide to say for sure. I was thinking I could put in an unfused cooker switch or just a cooker connector with flex outlet. Would that be OK or must it have its own radial circuit? The cable run is short but behind a wall of fitted kitchen units.

Here's the link if you care to see CMG676BS6B - http://www.bosch-home.co.uk/product-list/cooking-baking/microwaves/built-in-oven-with-microwaves/CMG676BS6B#/Tabs=section-technicalspecs/Togglebox=-1051994369/Togglebox=1169464653/ Under Additional information/Connection (not Connectivity) it gives all the info I have.

 

[hba]

I've just got through to Bosch, they say it can be connected to a 32A radial circuit so long as total load is under that (which it is). So they're not specifying a 16A fuse. This was an addition to a previous reply which I see is in a moderator queue because of a link, but I hope it means I could change the 13A switch for an unfused one or a cooker connector. Needs to fit in a standard 1 gang pattress box. Once again many thanks for your advice.

 

[Midwest]

Still not convinced myself, perhaps a more learned member will be along shortly.

I think the original install needs looking at, not sure how 6mm has been terminated into 2 x 13A FCU's?

Are you doing this or calling in an electrician?

 

[hba]

It's way thicker than 2.5mm but I've just learned there's such a thing as 4mm. I'll have a look to see it's properly connected. I'll probably upload a couple of pictures but may be a while.

If I was just replacing the switch with another switch I'd do it myself, if it needs a new cable run I'd get an electrician.

 

[Midwest]

In normal circumstance, I would have a 45A Cooker switch, controlling both appliances, and fed via Scolmore Dual Cooker Outlet Plate, to each appliance. If in the same location or housing obviously.

 

[Midwest]

It's way thicker than 2.5mm but I've just learned there's such a thing as 4mm. I'll have a look to see it's properly connected. I'll probably upload a couple of pictures but may be a while.

If I was just replacing the switch with another switch I'd do it myself, if it needs a new cable run I'd get an electrician.

A typical original 32A cooker supply in a domestic property would be 6mm tw&e.

 

[hba]

Here's the current setup. I think the main cable must be 6mm and the one joining the two switches 2.5mm.

 

[Richard Burns]

Because of the existing set up the most convenient way to go is to just replace one of the fused spurs with a 25A flex outlet plate and connect the microwave to that.
It may be worth checking that the rest of the circuit is undamaged whilst you are working on it.

 

[hba]

OK Midwest, so that's a 45A switch feeding a Scolmore Dual Cooker Outlet Plate. I'll link them with a short length of 6mm cable behind the back of the kitchen units. Both can fit on the existing surface boxes or I could get the longer box for the dual plate. Is that what you had in mind? It sounds like a good solution and will be compliant. Please let me know if I've got anything wrong, otherwise many thanks again for your patient advice!

 

[Pete999]

View attachment 42061 View attachment 42062 Here's the current setup. I think the main cable must be 6mm and the one joining the two switches 2.5mm.

Not done much Domestic lately, but I would have thought that athebest way would be to terminate the 6mm/4mm into a dual cooker outlet plate, and fused the appliances from that via 13 amp spur units. I await the disagrees with baited breath. along with any other criticisms, on my thoughts, but as usual open to any improvements from Domestic Installers out there.

 

[telectrix]

just change those 13A FCUs for 2 x 20A D/P switches. no need to fuse down as they are fixed loads and overload protection is not required. the 32A MCB will provide fault protection.

 

[GeorgeCooke]

Not done much Domestic lately, but I would have thought that athebest way would be to terminate the 6mm/4mm into a dual cooker outlet plate, and fused the appliances from that via 13 amp spur units. I await the disagrees with baited breath. along with any other criticisms, on my thoughts, but as usual open to any improvements from Domestic Installers out there.

Why would you fuse a 16 amp microwave with a 13 amp fused spur?

 

[GeorgeCooke]

Not done much Domestic lately, but I would have thought that athebest way would be to terminate the 6mm/4mm into a dual cooker outlet plate, and fused the appliances from that via 13 amp spur units. I await the disagrees with baited breath. along with any other criticisms, on my thoughts, but as usual open to any improvements from Domestic Installers out there.

Why would you fuse a 16 amp microwave with a 13 amp fused spur?

 

[hba]

Thanks to all for your advice. I think there are several valid options but have gone for a 20A DP switch with flex outlet and cable grip replacing the FCU that will go up to 16A.