Just a thought that crossed my mind... (45A)

Not after any proper answer to a problem as such..

more just a thought that crossed my mind whilst doing a job earlier this week...

I was installing a new cook circuit, and fitted a Crabtree cooker plate..

e.g.  https://www.toolstation.com/crabtree-45a-cooker-outlet-plate/p22152

Which is rated @ 45Amps...

And....

If we all know that cables and accessories should be capable of carrying the normal currents allowed by the protective device...

technically you can't connect a 45A cooker plate to a circuit supplied by a 50A MCB...

But Crabtree.. DONT actually make a 45A MCB, its 40A or 50A...   

i.e. Electrium product info jumps from 40A to 50A on their single pole MCB's..

https://www.electrium.co.uk/media/20150323155033_0_CrabtreeCCP.pdf

I Know MK have done a 45A MCB for a very long time now..

And Crabtree are not alone in this example, numerous other manufactures do not produce 45A MCB,s

So my thought was....

What is the point of a cooker connection plate rated @ 45A, if very few manufactures make a 45A rated MCB  ?????????????

:C

A 45A cooker switch is more likely to survive working at an actual load of 40A, than one that is rated at 40A

I notice most light switches are now rated at 10A, That does not mean you need to fit a 10A mcb for the light circuit.

Reality is that almost no ovens or cookers on the market will ever run, on a high load... For long enough to damage a switch

Unlike electric showers

Murdoch said:

Reality is that almost no ovens or cookers on the market will ever run, on a high load... For long enough to damage a switch

Unlike electric showers

Click to expand...

Presumably a 45amp switch should be capable of repeatedly breaking a 45amp load, which in practice will probably never happen, at least on a cooker circuit. 

I'd say it they chose an average current capacity  to suit average  cookers  .     Remember cooker plates & elements are constantly switching on/ off with  their stats .

As said above  ,  10A   light switches   and  20A  DP switches ...  would cover  the different types of load switching  without wearing out .  

Murdoch said:

Reality is that almost no ovens or cookers on the market will ever run, on a high load... For long enough to damage a switch

Unlike electric showers

Click to expand...

& electric boilers......... I was called out to a 10 - 12kw one that wasn't working this week.... it had a 45A DP switch as an isolator... I would have taken a photo of it if there was anything left of the mechanism to take one of

Murdoch said:

Reality is that almost no ovens or cookers on the market will ever run, on a high load... For long enough to damage a switch

Unlike electric showers

Click to expand...

Yes but they are only on for ...what ...10 mins  say  .       

I had a case of  a Triton shower that kept melting those two 16A micro switches inside .    It puzzled me as they usually last forever....  until I found out they were fostering a kid who was in the shower each day for an HOUR.