new shower

[aldino]

can you replace a 32amp mcb for a 40amp mcb on a consumer unit

 

[NuttallsSpark]

Normally yes it very easy depending on what type of fuse board you have

1 Whats the make?
2 Whats your main fuse amperage?
3 What size shower cable are you using and whats the ditance from the DB to the shower unit?

 

[Adam_151]

As long as the MCB is compatable with the consumer unit you wish to put it in, and a 40A device gives the correct level of protection to the circuit connected to that fuseway, then yes you can, unfortunatly I'm unable to advise you on either point as I've dropped and broken my crystal ball and have yet to aquire a replacement

 

[aldino]

thanks for info,the make of c/u is dorman smith,100amp switch and im upgrading my shower from 7.2 to 8.5kw hence i have to upgrade the mcb as the existing one is a 32amp

 

[NuttallsSpark]

Thats fine as long as the cable for the shower is a min of 6mm 10 mm is better.

 

[aldino]

thanks nutallspark,the exsiting cable is 6mm,i know the recommend 10mm.would that cause me probs keeping the 6mm

 

[NuttallsSpark]

6MM takes at best around 40A thats not takin into concideration distance of thermal effects i.e insulation or installation reference methods.

My recomendation whould be to replace with 10MM, But 6MM is a min

if the run is too long or the effects on the cable are too great the MCB will trip out protecting the cable if this happenes you will have to upgrade the CSA of the cable

 

[Spark123]

Thats fine as long as the cable for the shower is a min of 6mm 10 mm is better.

As long as it is clipped direct, kept away from insulation, (subject to volt drop, efli and ambient temperature.)

 

[aldino]

thanks,will change to 10mm to be on safe side

 

[Spark123]

if the run is too long or the effects on the cable are too great the MCB will trip out protecting the cable

Hmmm, no, not if the MCB is too big for the cable rating.

 

[NuttallsSpark]

Good this also means that if you upgrade in the future the cable will be ok and you can go upto larger KW showers. I have a 11Kw shower on a 50A MCB with 10MM.

Tip : get a thermostatic shower, more expensive but better in the long run , when someone turns the cold tap on you dont get burnt when the temp changes its a constant temp.