Oven on FCU? But what size fuse?

[alanl]

I've just been to change an oven tonight, should have been a straight swap.
Large cooker isolator, fine, MCB at 32A, no RCD protection. Not brilliant, but OK for a like for like.
Isolate, remove oven, then find the old oven is plugged into a double socket, with the hob ignition in the other plug.
Hmm, this is not right, so, I check the new oven, and see if it is rated low enough for a 13A plug fitting. No way, maximum demand 3.5kW, and Installation instructions say must be on a DP fused connector.
So, I'm going to have to fit a FSU, well 2 actually, as the hob needs sorting too. Then, because I'm modifying the circuit, I'll have to give it RCBO protection (cable <50mm).
*This is getting complicated for what should have been a 20 minute job.
Firstly, with a 3.5kW rating, the fuse needs to be 15A to cope with max demand. I cant say I've ever seen a 15A fuse. Use a 13A?

Is my thinking correct in this - it must be done right as it is a rented property.
Ta
Alan.

 

[telectrix]

but if you have a cooker isolator on a dedicated circuit, use that with a cooker outlet plate.

 

[GLENNSPARK]

Beat me to it lol


Sent from my iPhone using Tapatalk

on a pc at home so i guess its easier typing for me than on a phone mate

 

[Sparky Prime]

down grade to a 20 amp RCBO

 

[timo1]

I had exactly the same thing. Asked to wire up a cooker like for like. Original cooker on a 13a fcu spurred off kitchen ring. Looked at new cooker like you said its 3.5KW. Could not find the rating for the old cooker but obviously new is 15 + amps (possibly)

Problem is the place is a flat immaculately decorated no way could I run a new feed (cost single mum etc...) I am aware (or believe) that anything over 2KW should have its own dedicated circuit so I explained the situation to customer and connected the new cooker into the 13A RCD FCU (no RCD protection previously) as I thought I could apply diversity (first 10 amps then a third = 12A ish) as it would not all be running at the same time. I put this on the MWC and got customer to counter sign. this was over two weeks ago and no problems.

I know its not the best practice but the worst case scenario would be the fuse go? I have been trading for just over a year now and I find things like this crop up all the time, I can't just walk away principles get too expensive otherwise.

 

[GLENNSPARK]

If its fused then it needs to be accessable (not behind the cooker)! but i think most on here would know this already. At least then the cable has protection........

 

[Deleted member 26818]

That information is contained in Appendix 15.

 

[JD Hogg]

What app 15 says regarding connecting cookers etc over 2kW to their own dedicated circuit is not a regulation it is a method of ensuring the requirements of reg 433.1.5 can be met. What is important however is reg 433.1 which states "every circuit shall be designed so that a small overload of a long duration is unlikely to occur". I would suggest that putting a 15A cooker on a 13A fuse contravenes this.

 

[GLENNSPARK]

But isn`t it unlikely that the cooker will pull that much anyway?

 

[JD Hogg]

Yes, thinking about it the oven would get up to temperature, probably pulling 15A then the stat would switch it on and off as required so the overload wouldn't be a long duration.

There is no way 15A would blow a 13A fuse so feeding the oven via a plug top is OK then??

 

[yellowvanman]

Appendices in the regs are 'informative and are provided as guidance' - which means they don't have to be followed exactly.

This was highlighted recently to me by an ECA assessor.

 

[Deleted member 26818]

Appendices in the regs are 'informative and are provided as guidance' - which means they don't have to be followed exactly.

This was highlighted recently to me by an ECA assessor.

Excepting Appendix 1, which is normative and is thus a requirement.

 

[Engineer54]

If that oven ever see's 15A it'll be a miracle!!! This is almost becoming a daily occurance on the Forum, of where sparks can't get it round their heads that these ovens are rated at ''connected load'' and that connected load is unlikely ever to be seen, because there are heating/cooking elements that cannot be utilised at the same time!!!

Some of the posts on this thread, clearly indicates that there is a lack of understanding whenever they come up against cookers, ovens, and split hob and oven set-ups. They still look at the total KW rating and start panicking, and up goes the size of the cable and the MCB rating, all to the cost of their customers.

This oven can go on an FCU with a 13A fuse, ....end of!!!