32amp to 40 amp

[ZUNDAP]

Hi, i am looking for information regarding wiring in a shower, the last one i fitted used a 32 amp fuse in the consumer unit, but my new shower requires a 40 amp fuse, so my question is, Can i just replace the 32 amp fuse in the Consumer Unit with a 40 amp one?

Thanks in advance for any replies.

 

[ricicle]

No. You need to find out :-

Size of cable, length of cable, how it is ran and what type of protective device is used. Also whether or not you have existing 30mA RCD protection on the circuit.

 

[ZUNDAP]

Thanks for the reply recicle, could you tell me how i find out what size cable is required

And could you tell me how to find out what kind of RCD protection i have all ready?

My consumer unit does have trip out if there is a surge in power, or a short out. Are they all 30mA?

Thanks.

 

[ZUNDAP]

It is a Galaxy Serene 9.5 kw shower.

 

[PrenticeBoyofDerry]

It is a Galaxy Serene 9.5 kw shower.

What does the manufacturers instruction state as required cable size?
A 40A applaince would require at least 6.00mm T&E on full load, but there are other variables to take into consideration, such as cable length, method of installation such as trunking, conduit, within thermal insulation.
RCBO

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• PrenticeBoyofDerry
• 25 Apr 2012
• 5

RCCB

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• PrenticeBoyofDerry
• 29 Jul 2009
• 5

they have test button on and should state 30mA on them.
Have you got pictures of your set up as not all are 30mA, could depend on your earthing arrangement.

 

[ZUNDAP]

Thanks for the reply PrenticeBoyofDerry, the thing is that i bought the shower some years ago and have only just got round to fitting it and in that time i have lost the instructions that came with it.


The cable will run 20 meter's at the absolute maximum.

The cable will run up to the loft via cupboards, along the loft for about two metres and then the final metre will be under the plaster in the bath room, so there will be no trunking at all.

On the fuse for the old shower unit it says - M6 Type 1, 32amp and at the bottom of the fuse it says 321 QEB. On the face of the consumer unit it says.
MEM MEMEMER 21
Type tested to BS 5486 PT13
Total loading 80 amps maximum. - not be EXEEDED

It looks very much like the fuse in the top picture that you posted and there is a test button.

Does that help?

 

[ericmark]

Type 1 means its quite old now we have B, C, and D not 1, 2, 3, and 4. Which means it was in the era when ELCB-v were used these are now banned and have been replaced with ELCB-c better know as the RCD.

The voltage type did have a test button but no ratting like 100ma or 30ma marked on them as voltage operated not current operated often not built into the consumer unit but a stand alone unit which the earth wire went to.

The reason they were banned was earth bonding could short them out and stop them working. I would suggest posting a picture.

6mm sq cable can be anywhere between 23.5A and 58A according to insulation and route I would as rule of thumb consider it to be 34A that's Reference Method 100# (above a plasterboard ceiling covered by thermal insulation not exceeding 100 mm in thickness). So likely you would need to renew the cable to increase MCB size.

9.5kW is 41.3A and is unlikely to work for more than 5 mins on a 32A MCB and if the board is fitted with type 1 you may find new MCB's are just not available.

But if the house is protected by a ELCB-v that's far more important to correct than fitting any shower so step one get that photo up and lets see what you have.

 

[ricicle]

6mm sq cable can be anywhere between 23.5A and 58A

47A is the max. possible for 6mm² t+e.

 

[ban-all-sheds]

Thanks for the reply recicle, could you tell me how i find out what size cable is required.

• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
  

 

[securespark]

6mm sq cable can be anywhere between 23.5A and 58A

47A is the max. possible for 6mm² t+e.

47A is indeed the max. for clipped direct.

You can go up to 51A using free air or perforated cable tray installation methods, which would be highly unlikely in a domestic situation.

 

[ZUNDAP]

I have taken photo's, but i don't know how to post the photo's here, could anyone tell me how i do that? Thanks.



[/img]

 

[333rocky333]

//www.diynot.com/forums/viewtopic.php?t=129539

 

[ZUNDAP]

slips

 

[ZUNDAP]

6mm sq cable can be anywhere between 23.5A and 58A

47A is the max. possible for 6mm² t+e.

47A is indeed the max. for clipped direct.

You can go up to 51A using free air or perforated cable tray installation methods, which would be highly unlikely in a domestic situation.

Thanks for those links ban-all-sheds, they are very handy to have.

 

[ZUNDAP]

Here are the pics of the cu

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• ZUNDAP
• 19 Aug 2012
• 1

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