memera 2000 shower installation

[jona77]

Hi, looking for a bit of advice, I'm looking for a mem rcbo to cover a 10.8kw mira vie shower, now the manual states a 45 amp fuse for the 10.8kw, thats for a 240v supply. The uk is 240v, so 45 amp it is. I'm using about a 4 metre cable run at 10mm, of which about half will be behind plasterboard. Memera dont do 45 amp rcbos for some reason, so i'm looking at either a 40 amp or 50 amp, and i would think 50 amp would be the way to go, but then again, dont these CU fuses usually take a good bit more current than there rated capacity before they blow ? i've seen quotes they can take 1.8 times more than there capacity, which would make me think maybe the 40 amp rcbo would be better suited. Any advice would be appreciated.

Also, why does memera, or eaton, not do a 45 amp rcbo ? Is it that these boards are outdated, it seems kind of strange given theres a lot of these boards around, and there not exactly ancient. I mean i want to follow the shower manufacturers specs, but that is impossible to do.

 

[ban-all-sheds]

I'm using about a 4 metre cable run at 10mm, of which about half will be behind plasterboard.[

Check what installation method that equates to - 10mm² cable may not be rated at 50A for it.

Any advice would be appreciated.

• 
  
  
  
• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm (all subsections)
  
  
• http://www.tlc-direct.co.uk/Book/4.3.11.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
  
  
• http://www.tlc-direct.co.uk/Book/5.3.1.htm
  
  
• //www.diynot.com/wiki/electrics:mcb2
  
  
• http://www.tlc-direct.co.uk/Book/8.1.1.htm
  
  
• //www.diynot.com/wiki/electrics:part-p
  

 

[kai]

One way round the problem, is to use a B50 breaker to feed a separate one way consumer unit which is (B45 breaker compatible), complete with 30mA RCD as a switch - the safest and easiest way to solve the problem.
Using a separate RCD and B45 breaker may be better, as the RCD gives double pole isolation, and may be more economical too.