Upgrading the rating of an MCB

[jeffO]

My consumer unit has an MCB rated at 32amps for my shower. The shower supply recommends that it should be 45amps. How do I fit an MCB with a higher rating? Must I get an electician to do this?

 

[Scoby_Beasley]

They clip/attach to what is known as a "busbar", turn off your power and place the highest amperage mcb next to your incoming isolator, this could mean some juggling about of your other mcb's, but highest rating should go next to incoming supply and work your way down the further away you go.

 

[ban-all-sheds]

Jeff0 - what size cable supplies the shower?

 

[jeffO]

Many Thanks to Scoby.

Regarding cable size, I'm failry certain that it is 25 amp. The showering unit is rated as 9.5 [/list]

 

[supersparks]

Many Thanks to Scoby.

Regarding cable size, I'm failry certain that it is 25 amp. The showering unit is rated as 9.5 [/list]

25amp?,,,,,so its 2.5mm supplying a shower of 9.5kw.............wouldent use that anymore untill that upgraded, or you might end up with a new toster....

 

[ban-all-sheds]

So you have a 25A cable, protected by a 32A breaker, and you want to know how to replace the breaker with a 45A one

You should get an electrician in - not just to replace the MCB, but also to replace the cable with 10mm, and check for any other wiring hazards you have...

 

[breezer]

jeffO i must agree with the others, but for your future reference cable is measured by its physical size. if you were to run your shower from the existing cable (having changed the mcb) the existing cable will not be big enough to carry all the current required and it will get very hot, possibly red hot and cause a fire.

in short dont do it , and also there is the question of positiong th mcb, there is an order they should go in.

best get several quotes from a qualified electrician

 

[Scoby_Beasley]

Bleedin' Hell, have I just killed someone as their cable was under-rated? I'm gonna have to keep off this web site 'cos I assume people know what size cable they should use for different situations

 

[Millennium_Boy]

Bleedin' Hell, have I just killed someone as their cable was under-rated? I'm gonna have to keep off this web site 'cos I assume people know what size cable they should use for different situations

IF IN ANY DOUBT ABOUT ANY ELECTRICAL WORK/ ESPECIALLY THAT FEEDING A BATHROOM OR SHOWER, YOU MUST GET A PROFESSIONAL ELECTRICIAN TO SORT IT OUT FOR YOU - BS7671:2001 QUITE RIGHTLY EMPHASISES THE VERY HIGH SHOCK ELECTROCUTION RISKS PRESENT IN A BATHROOM OR SHOWER ROOM.

 

[supersparks]

IF IN ANY DOUBT ABOUT ANY ELECTRICAL WORK/ ESPECIALLY THAT FEEDING A BATHROOM OR SHOWER, YOU MUST GET A PROFESSIONAL ELECTRICIAN TO SORT IT OUT FOR YOU - BS7671:2001 QUITE RIGHTLY EMPHASISES THE VERY HIGH SHOCK ELECTROCUTION RISKS PRESENT IN A BATHROOM OR SHOWER ROOM. [/quote]

I think you pose more of a health risk:

"I am afraid, that your husband was killed by bordom on the subject of 7029, we are serching high and low for the culprit, MB, but it appears he went for a cheap, two piece pocket fabric,and has fallen through it and is lost......"

AR

 

[ban-all-sheds]

Bleedin' Hell, have I just killed someone as their cable was under-rated? I'm gonna have to keep off this web site 'cos I assume people know what size cable they should use for different situations

I expect they managed to get out before the fire really took hold

What have you been told about assuming? (Yeah, right, like I never do... )

Jeff0 was asking how he could replace his already-too-big MCB with one even bigger, because he has a 9.5kW shower. Presumably a new shower.

So I fear he may not be aware of what size cable to use - he didn't ask what he should use, or how to replace it, so either he wasn't planning to do anything about the cable, or he does know, and does plan to replace it. But wouldn't someone who knew how to replace the cable from the CU to the shower also know how to replace an MCB

 

[Scoby_Beasley]

Phewwww!!!!!!! Let off again then
I agree ban-all, assumption is a v dangerous thing, even in my job which is working with 500c alloys dont assume cos u canna tell the diff between hot n cold, G'luck so

 

[breezer]

[
So I fear he may not be aware of what size cable to use - he didn't ask what he should use, or how to replace it, so either he wasn't planning to do anything about the cable, or he does know, and does plan to replace it. But wouldn't someone who knew how to replace the cable from the CU to the shower also know how to replace an MCB

as you said "never assume ANYTHING"

 

[Scoby_Beasley]

I'm no sparky but have re-wired two houses to date, IF IN DOUBT ALWAYS "OVERWIRE", better safe than very sorry (showers are one /the one/ major dangerous appliances in your house, electricity meets water, tread with care, connect up, then check again)

 

[ban-all-sheds]

[
So I fear he may not be aware of what size cable to use - he didn't ask what he should use, or how to replace it, so either he wasn't planning to do anything about the cable, or he does know, and does plan to replace it. But wouldn't someone who knew how to replace the cable from the CU to the shower also know how to replace an MCB

as you said "never assume ANYTHING"

Yo - as I was typing it I was thinking, "am I assuming that he does know how to replace a cable, or deducing that he hasn't though of it?"

When does reasoned deduction become assumption?

I dunno...