Shower & RCB query

Discussion in 'Electricians' Talk' started by markf, Apr 21, 2004.

  1. markf

    markf New Member

    I've just fitted a new shower in my friends house, the problem is when I checked, there is no RCB in sight and since the old unit was soaking wet inside I guess there is not one. This is no great problem, I'll just fit a shower unit for it (baths only in the meantime). But my main query is why this was not picked up in the estate agent survey done about 18 months ago, as a shower without an RCD is potentially lethal.
     
  2. cpc

    cpc Member

    I've just fitted a new shower in my friends house,
    the problem is when I checked, there is no RCB in
    sight and since the old unit was soaking wet inside I
    guess there is not one. This is no great problem,
    I'll just fit a shower unit for it (baths only in the
    meantime). But my main query is why this was not
    picked up in the estate agent survey done about 18
    months ago, as a shower without an RCD is potentially
    lethal.
    BS7671 part 6 Section 601,please read fully and then tell me if you need an RCD on a shower.
     
  3. cpc

    cpc Member

    P.S estate agents DONT check the wiring.
     
  4. sparks

    sparks New Member

    There is no requirment in BS 7671 to fit an RCD device to a circuit suppling a shower, the bathroom or shower room is regarded as a special location and the earth bonding requirements for a special location must be met and the electrical equipment used within it must be suitable for use in such a location and correctly positioned so as to conform to the regulations. A shower will probably be fitted in zone 1 and therefore must have an IP rating ofIPX4 or IPX5 if it is to be hosed down, often the shower unit is marked with regard to its IP rating but often it is not. Having said all this some manufacturers recommend the fitting of an RCD to their product and this being the case it would be wise to follow their advice. As to the estate agent failing to spot this as someone else pointed out they do not inspect the electrical installation in a survey although some surveyors will recommend a periodical electrical inspection as a condition of the mortgage.
     
  5. Lectrician

    Lectrician Screwfix Select

    RCD not required (unless of course TT earthing :) )

    Aslong as the Zs is low enough to operate the protection (fuse or mcb) with in 0.4secs. Obviously beyond a diyer to test this, but the max pme Ze is 0.35ohm, and the max Zs on a 40amp B breaker is 1.2ohm i think, so you have plenty of length before there would be a problem
     
  6. The Trician

    The Trician New Member

    Go to the MIRA Showers website - I think they have one.
    They do a really handy guide to cable/length of cable run/cable types/volt-drop calcs etc etc.

    Write to them and ask for 'A MIRA Guide to electric shower installations (7.0KW - 10.8KW) 7th edition.
     
  7. eawr89

    eawr89 New Member

    There is no longer a requirement in BS7671 to disconnect this circuit within 0.4 seconds, 5 seconds is now permissible.
     

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