Currys instal is it right?

[Bandqtosser]

A elderly Aunt has bought a double oven and 4 ring hob from Currys, she paid to have it installed by there delivery driver,he has connected both in parrellel to the existing cooker outlet that includes a switched 13A socket, this is feed via 6mm T&E from the consumer unit in the garage approx 30ft away, the consumer unit is the old rewireable fuse type.
I have calculated the total approx power if every thing was switched on and a kettle pluged in to be approx 10.7Kw, therefore a current flowing of approx 45Amps, knowing how uncertain rewireable fuses are do you considder the instal safe, are they allowed to assume the divercification factors, considdering there limited skill.

 

[securespark]

DIVERSITY....

She is unlikely to have everything blasting away at once.

And if she does, it will just pop the fuse.

Diversity allows this set up on a 30A circuit.

 

[ban-all-sheds]

A elderly Aunt has bought a double oven and 4 ring hob from Currys.

Definitely your Aunt, not your old Naan?

 

[Bandqtosser]

I am not still not convinced its safe, she might not use all at once but the next resident might one Xmas day, as you say the fuse SHOULD rupture first, but how good are rewireable fuses and there cut off time I understand is also slow.
I do think its a case a "unqualified" person doing a properly skilled electricians job, because how much does the Currys man know about diversication, and other factors such as the cable route, and its envirement etc etc.

 

[BS3036]

You are talking about 2 different things.

- Is it correctly wired?

- Should delivery men wire in appliances?

You had an answer to the first which you don't believe.

The On-site guide says that in this situation, because of diversity considerations, you allow 10A plus 30% of the remainder for the appliance, plus 5A for the socket. I make that around 22.5A although I had to guess because you didn't state the appliance max power.

What you have to realise is that all the rings and ovens could be on, but will rarely all be be drawing current at the same time. And the heating effect in the cable is integrated over a few minutes, which is reflected in the way the fuse works.

As for the delivery man's competence - who knows?

 

[ban-all-sheds]

I am not still not convinced its safe, she might not use all at once but the next resident might one Xmas day, as you say the fuse SHOULD rupture first, but how good are rewireable fuses and there cut off time I understand is also slow.

But that has nothing to do with whether the load is too great. Provided the relationship between the cable size, length & installation method, and therefore current carrying capacity & R1+R2 and the protective device rating with any factors that apply there, is OK then an overload may take the fuse out but it won't be dangerous.

I do think its a case a "unqualified" person doing a properly skilled electricians job,

Installing an appliance?

because how much does the Currys man know about diversication,

Don't know, but the calculation is a standard one, so Currys might have a table of what cooker sizes can be supported on what fuse.

If the circuit has a 30A fuse then taking account of the socket on the CCU diversity allows you to put a 13.8kW cooker on it.

and other factors such as the cable route, and its envirement etc etc.

Whether a 30A fuse is appropriate for that particular cable in your Aunt's house is another matter, but if it's not then it's not, no matter what is connected to it, and vice-versa.

 

[Bandqtosser]

Many thanks for the last reply, and the last indepth explanation, I was unable to get the exact power consumption figures but I guessed at 4.5Kw for the hob and 2.5Kw for each of the two ovens + for a 2.5Kw kettle.
I can see the point it is unlikely that all the thermostats will be closed at the same time.
However I think I might swap the fuse for a plug in MCB, it would be safer and easyer for her to reset if needed.
thanks again
BandQtosser

 

[ban-all-sheds]

Many thanks for the last reply, and the last indepth explanation, I was unable to get the exact power consumption figures but I guessed at 4.5Kw for the hob and 2.5Kw for each of the two ovens

If that's right then the standard diversity calculation says the circuit has to be rated for 20A, or 25A if there's a socket.

However I think I might swap the fuse for a plug in MCB, it would be safer and easyer for her to reset if needed.

You will remember to notify the council first, won't you...

 

[Bandqtosser]

Really does swapping a plug in MCB come under part P reg !!!

 

[ban-all-sheds]

1) It comes under Part P because it is work on the electrical installation of the house.

2) It's notifiable because it is not one of the jobs listed in Schedule 2B.

 

[securespark]

OOI, did the fitter leave any paperwork or test results to say the work he'd done was safe?

 

[jaisol99]

Hi

Doumb question but whats schedual B. I do industrial electrics.

I would disagree with the comments about it being notifiable, the wire fuses I'm guessing old wylex banger box, are designed to be replaced/rewired by end users all he is going to do is plug in a replacement fuse.

Just a thought fuses BS88 - they use fuse wire will blow before an mcb trips under moderate overload conditions.
I agree from a convenience point of view if it blows then a mcb its far easier to reset for a non electrical person

 

[mattysupra]

dont all new cookers run on alot less power? I was told that all new stuff only needs 2.5mm as low power, not like the old stuff needing 6mm+ cable size.

Is this correct or have i been informed wrong?

 

[skenk]

A lot of lower end models 2.5 is fine but when you start talking double ovens, electric hobs etc then it can be a lot more. I'd tend to stick with 6mm if putting in a cooker circuit, it just depends on the rating of the cooker.

 

[ban-all-sheds]

Doumb question but whats schedual B. I do industrial electrics.

See page 34.

I would disagree with the comments about it being notifiable, the wire fuses I'm guessing old wylex banger box, are designed to be replaced/rewired by end users all he is going to do is plug in a replacement fuse.

No - he is carrying out installation work which is not exempt from notification.

Just a thought fuses BS88 - they use fuse wire will blow before an mcb trips under moderate overload conditions.

Can you get BS88 carriers for those old Wylexes?