Amp rating on spur - 2.5mm Cable

[Neptune]

Can I please check my understanding on the following.
My ring is wired in 2.5mm T&E. It is on a 32 amp MCB and protected by an RCD.

I am now contemplating a spur from one of the ring circuits to provide power to an electric hob. The Hob is 2.5KW which I believe, equates to 11 amps. If this is the case, the single 2.5mm cable to the spur socket should be fine.

Thanks in advance.

 

[timhoward]

If this was an isolated question for a one-off DIY job I'd answer it.

But it's a little bit cheeky repeatedly asking people who've spent serious chunks of change over the years on training courses, regs books, guides, insurance etc. to just tell you how to wire your house. Splitting it all up into separate threads doesn't ultimately stop it being step by step advice.
Your project involves a shower room so is a notifiable job. Lots of us pay hundreds of pounds a year to be able to notify work and do things right.

It seems that you won't pay for a qualified sparks, you won't pay for a copy of the regs (~ £90) , you won't pay for a training course to help you understand them (~£100 for basic online course) , but you want us to walk you through everything one task at a time.
If you were in our position would you humour someone who did this?

This isn't about your ability - I actually believe you would do a good job if you invested in learning what you need to know.

 

[Neptune]

If this was an isolated question for a one-off DIY job I'd answer it.

But it's a little bit cheeky repeatedly asking people who've spent serious chunks of change over the years on training courses, regs books, guides, insurance etc. to just tell you how to wire your house. Splitting it all up into separate threads doesn't ultimately stop it being step by step advice.
Your project involves a shower room so is a notifiable job. Lots of us pay hundreds of pounds a year to be able to notify work and do things right.

It seems that you won't pay for a qualified sparks, you won't pay for a copy of the regs (~ £90) , you won't pay for a training course to help you understand them (~£100 for basic online course) , but you want us to walk you through everything one task at a time.
If you were in our position would you humour someone who did this?

This isn't about your ability - I actually believe you would do a good job if you invested in learning what you need to know.

oh, I have an onsite guide and have also been working through a series of Learn Electricians video.
The understanding of cables and ratings in my post above comes from what I learnt in the OSG.

I am starting to feel that you don't want to help me irrespective of what I do @timhoward

 

[timhoward]

oh, I have an onsite guide and have also been working through a series of Learn Electricians video.
The understanding of cables and ratings in my post above comes from what I learnt in the OSG.

It would have been worth mentioning you have been making these efforts. I apologise if I sounded frustrated as its been sounding like you weren't making any effort to learn yourself.

It will only be drawing 11 amps if all elements are turned on at same moment, in reality this won't happen as they will cycle on and off on thermostats.
Only you know what else is on the circuit. Circuits have to be designed so a small overload of long duration is unlikely to occur.

A ring final circuit requires any one part not to draw more than 20 amps. It would be more belt-and-braces to not be on a spur but from what you have said I don't see a problem.

 

[westward10]

Here we go again. It is recommended a fixed load of 2.5kw should not be connected from a ring final circuit.

 

[Neptune]

It would have been worth mentioning you have been making these efforts. I apologise if I sounded frustrated as its been sounding like you weren't making any effort to learn yourself.

It will only be drawing 11 amps if all elements are turned on at same moment, in reality this won't happen as they will cycle on and off on thermostats.
Only you know what else is on the circuit. Circuits have to be designed so a small overload of long duration is unlikely to occur.

A ring final circuit requires any one part not to draw more than 20 amps. It would be more belt-and-braces to not be on a spur but from what you have said I don't see a problem.

Apologies for not being explicit about this but I have been reading and viewing content for some time now. I am not planning to be an electrician (you'll be pleased to hear!) but I do find it fascinating. Particularly, the planning and fault finding aspects of it. I recently purchased a Megger MFT

However, it's not second nature for me - like it is for many of you I suspect. That's where I find your expertise immensely helpful. Since I am not doing it every day, there isn't an opportunity for it to become habitual. Thanks for bearing with me.

I am also interested in the online course you suggested above. Can you please point me to the relevant course.

Thanks for your help.

 

[Neptune]

Here we go again. It is recommended a fixed load of 2.5kw should not be connected from a ring final circuit.

Won't it be a variable load as burners will be clicking in and out and we may not have all the burners on at the same time?

 

[timhoward]

Here we go again. It is recommended a fixed load of 2.5kw should not be connected from a ring final circuit.

Won't it be a variable load as burners will be clicking in and out and we may not have all the burners on at the same time?

Apologies, I was trying to keep this simple and not get in the Appendix 15 debate...my thinking was that for 99% of the time it won't exceed the 2Kw, except maybe on Christmas day. However, really, the plated max power consumption is what should be used when considering Appending 15 guidelines.

@Neptune In the full regs book there's an appendix with informative sample circuits. I can't remember if/where its in the OSG. It's not obligatory to follow them as long as the circuit design current < over current protective device < cable rated current (and the special reg for ring final circuits is met).
It does recommend that cookers, ovens and hobs over 2Kw are on their own dedicated circuit. That would be best practise.

I am also interested in the online course you suggested above. Can you please point me to the relevant course.

One example, which I used myself as I jumped from 16th edition to 18th edition with a long break in the middle:

18th Edition Online Course - C&G 2382-22 (Amendment 2)

We will go through the book from cover to cover and highlight everything you need to pass the 18th Edition exam!

www.learnzonemedia.co.uk

 

[Lucien Nunes]

Each ring on a hob can be up to 2.5kW - I find it remarkable that the whole hob is rated at 2.5kW. What model is it?

 

[Electro-tech]

Here we go again. It is recommended a fixed load of 2.5kw should not be connected from a ring final circuit.

Glad to see the use of Verbal forms used in BS 7671 in one sentence.

 

[swaRRR]

Here we go again. It is recommended a fixed load of 2.5kw should not be connected from a ring final circuit.

Have you got a reg citation for that? Just want to look it up for a read

Although electrically sound (a kettle will draw the same power and is simply plugged into a socket on a ring final) i just wouldn't put cooking appliances on an FCU off a ring final. Can't even justify why or why not, just something tells me not to do it.

Keeping electrical separation between higher powered appliances would be my go-to. Some might argue why not the same with a kettle but hobs can be on for 30 mins + and a kettle can't be.

 

[westward10]

Have you got a reg citation for that? Just want to look it up for a read

Although electrically sound (a kettle will draw the same power and is simply plugged into a socket on a ring final) i just wouldn't put cooking appliances on an FCU off a ring final. Can't even justify why or why not, just something tells me not to do it.

Keeping electrical separation between higher powered appliances would be my go-to. Some might argue why not the same with a kettle but hobs can be on for 30 mins + and a kettle can't be.

As I said it is a recommendation see Appendix 15.

 

[swaRRR]

As I said it is a recommendation see Appendix 15.

Thanks will give it a thorough perusal.