shower mcb question

[paulthemagpie]

hi,

just needed a bit of advice.

ive bought a 10.5kw shower installed it with 10mm cable and a 45a pull cord. I cant seem to find a 45a legrand mcb anyway will it be okay to use a 50a legrand one?

thanks paul

 

[telectrix]

if your 10mm is ref. method C,E or B, you'll just get away with a 50A MCB. if in an insulated wall, the CCC is only 43A.

 

[paulthemagpie]

hi,

thanks for the reply.

I know a 50a mcb would be fine. But what i was getting at is will a 50a be fine with the fact ive used a 45a pull cord?

 

[telectrix]

yes. the 45A is the max. continuous load that the pull switch will handle. it's not a trip value.

 

[GLENNSPARK]

Paul...use a 40 type B...it`l hold ok.....for longer than anyones gonna use that shower anyway....

 

[paulthemagpie]

so you would suggest using a 40a over a 50a?

also does anyone know why legrand dont do the 45a mcb's?

 

[GLENNSPARK]

i dont think their common for most brands now Paul.....its the same as 25A MCBs..their listed in BS7671.....but you try lookin for em in...lets say screwfix...or summat like that....
the thing is though Paul....if you don`t know/cant verify the installation method used...then as Tel has pointed out.....
so go under for you OPD rather than over...protect your install....
and don`t forget that manufacturers often overrate their products....
once you`v juiced it up...stick it on full whack....clamp it.....you may get a surprise

 

[paulthemagpie]

with the ccc being 43a, i thought the 40a would of not being suitable

 

[GLENNSPARK]

no...it`l be allrite Paul....
like i say...after you`v powered it up..full...clamp it.....bet its no`whare near..lol

 

[paulthemagpie]

if your 10mm is ref. method C,E or B, you'll just get away with a 50A MCB. if in an insulated wall, the CCC is only 43A.

installation is in false wall and then under floor boards.

 

[GLENNSPARK]

dont forget Paul....your protecting your cables......you cant verefy the installation method for em....so you have to work on worst case (within reason)....your the designer....so you make the call...

 

[GLENNSPARK]

installation is in false wall and then under floor boards.

go for Method C then here Paul....
but stick to 40A OPD...just in case..

 

[paulthemagpie]

go for Method C then here Paul....
but stick to 40A OPD...just in case..

okay thanks for the help.

so get a 40a and put it on full wack. if it doesnt trip we good to go.

 

[GLENNSPARK]

okay thanks for the help.

so get a 40a and put it on full wack. if it doesnt trip we good to go.

put the shower on full whack....and get a current clamp out...clamp it Paul....see what your really getting........bet it isn`t 43A...lol..

 

[Octopus]

2 thoughts:

1. If its a pull cord switch ALWAYS use the Crabtree 50A
2. Fit a 40A breaker

 

[paulthemagpie]

the pull cord is a 45a which is already installed. So will fit a 40a breaker.

 

[telectrix]

33 mins @ 60A for a 40A type B to trip. anyway.