Garage Consumer Unit

[Chit]

Hi - thanks for all that, so is that dangerous in that case....?

Do you guys know what the following circuits should have in the CU in that case ? Bit worried now and wondering that the other circuits may be fitted with the wrong ratings too?

There is....

1. dowstairs lighting circuit
2. upstairs lighting circuit
3. passage and front room ring final circuit (power sockets)
4. back room and conservatory ring final circuit (power sockets)
5. kitchen ring final circuit (power sockets)
6. radial shower circuit (although i think the shower manual states that the rating should be what it is alread)
7. radial oven circuit (again already stated in the manual as well).
8. radial immersion heater circuit.
9. radial garage circuit - lights and sockets powered off of the same circuit (as already stated).

Many thanks

 

[ban-all-sheds]

I was very aware of John had posted, but felt the need to make the point just incase, someone took my post literally without taking the reffered post by John in to consideration.

Yes.

But it was your choice to partially quote John, omitting the vitally important caveat.

You see I remember full well that before you edited it, your post read

I see nothing wrong with his present set-up.

Me neither.

 

[ban-all-sheds]

1. dowstairs lighting circuit
2. upstairs lighting circuit
3. passage and front room ring final circuit (power sockets)
4. back room and conservatory ring final circuit (power sockets)
5. kitchen ring final circuit (power sockets)
6. radial shower circuit (although i think the shower manual states that the rating should be what it is alread)
7. radial oven circuit (again already stated in the manual as well).
8. radial immersion heater circuit.
9. radial garage circuit - lights and sockets powered off of the same circuit (as already stated).

1. 6A
2. 6A
3. 32A
4. 32A
5. 32A
6. Depends on cable size and how it's installed:
   
   //www.diynot.com/wiki/electrics:mcbtocable
   
   http://www.tlc-direct.co.uk/Book/4.3.1.htm (all subsections)
   
   http://www.tlc-direct.co.uk/Book/4.3.11.htm
   
   http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
   
   http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
   
   http://www.tlc-direct.co.uk/Book/5.3.1.htm
   
   //www.diynot.com/wiki/electrics:mcb2
   
7. Ditto
8. Almost certainly 16A or 20A
9. 20A
   

 

[PrenticeBoyofDerry]

But it was your choice to partially quote John, omitting the vitally important caveat.

Which is very true, which was the reason for the edit.
I did not want to indicate that there was nothing wrong with the set up as it stood. As there was the issue with 32A protecting 2.5mm T&E.
In hindsight it would have been a little less of a concern for yourself if I had re-edited John's quote with the addition, rather than make the edit I did.
Unfortunately in my keenness to agree with John's very finely composed post, I did initially overlook the importance of making the quote in it's entirety.
I do apologize most sincerely

 

[ban-all-sheds]

Don't let it happen again, or you'll be beaten with a wet copy of BS 7671.

 

[PrenticeBoyofDerry]

now your getting kinky

 

[Space cat]

With two double sockets and an FCU in the garage already, I would complete the ring (with 2.5mm cable) back to the existing 32 amp breaker.

 

[JohnW2]

With two double sockets and an FCU in the garage already, I would complete the ring (with 2.5mm cable) back to the existing 32 amp breaker.

You might have that need, but why bother if (as I suspect is the case with the OP) one knew that 17A (plus 3A for lighting) (and a 20A MCB) was more than enough for one's current requirements? If the situation changed in the future, one could always 'complete the ring' in the fashion you describe and re-instate the 32A MCB.

Kind Regards, John.

 

[Chit]

1. dowstairs lighting circuit
2. upstairs lighting circuit
3. passage and front room ring final circuit (power sockets)
4. back room and conservatory ring final circuit (power sockets)
5. kitchen ring final circuit (power sockets)
6. radial shower circuit (although i think the shower manual states that the rating should be what it is alread)
7. radial oven circuit (again already stated in the manual as well).
8. radial immersion heater circuit.
9. radial garage circuit - lights and sockets powered off of the same circuit (as already stated).

1. 6A
2. 6A
3. 32A
4. 32A
5. 32A
6. Depends on cable size and how it's installed:
   
   //www.diynot.com/wiki/electrics:mcbtocable
   
   http://www.tlc-direct.co.uk/Book/4.3.1.htm (all subsections)
   
   http://www.tlc-direct.co.uk/Book/4.3.11.htm
   
   http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
   
   http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
   
   http://www.tlc-direct.co.uk/Book/5.3.1.htm
   
   //www.diynot.com/wiki/electrics:mcb2
   
7. Ditto
8. Almost certainly 16A or 20A
9. 20A
   

Thanks for that, checked last night and all of the other ratings are correct. Wondering why the rating for the garage is 20A and the dowstairs sockets is at 32A?

Is this because the garage is a radial circuit and the others are ring finals? What's the theory behind this?

 

[Space cat]

What's the theory behind this?

Simple. If you look at the way a ring works, you'll see that current can reach any point on it by two different routes. The cables on each side of it share the load. Now each cable can carry 20 amps but, because of different lengths, you can't assume that it'll divide equally (in fact that's highly unlikely) so the ring as a whole is given a rating of 32 amps. When it's on full load, it's assumed that the split will be no worse than 12 - 20 so no part of it will be overloaded.