RCD or Switch First

2 Jan 2007
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United Kingdom
Just purchased new power shower and it states that a 30mA RCD and double pole fused 3 amp isolating switch should be installed, my question is;
from the ring circuit which do I fit first RCD or Isolating switch.
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What sort of RCD do you have? If you have an RCD FCU this may provide adequate protection. Depending where the pump is going, this work may be notifiable to your LABC under part p of the building regs.
Does your ring circuit not already have 30mA RCD protection?
Have not yet purchased the RDC.
Ring circuit does not have RDC only fused system.
The pump is internal in the power shower unit, which will be in the bathroom, Isolation switch and RDC will of course be outside of the bathroom, but I am not certain which one should be first in line from the Ring circuit.
Depends where you're going to mount the fused connection unit and how you run the cable to it. If the cable is going to be concealed beneath the plaster at less than 50mm from the surface then the cable itself will also require 30mA RCD protection. In this case it would be of benefit to install protection at the consumer unit if possible.
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RCD will be mounted on wall outside bathroom, as will isolating switch, cable will runn through partition wall 4 inches wide, so no problem with the cable run.
So the cable will end up concealed less than 50mm from the surface (one side or the other)?
Just chipping in - isn't a power shower meant to be on its own dedicated circuit rather than off a ring circuit? Or have I read this wrong? :oops:

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