The article ‘Consumer demand’ by Colin McAhren in the February 2009 issue of EMC is very informative and interesting

However, there appears to be one point which is clearly overlooked within McAhren’s feature. In illustrations four and five, the shower, immersion heater and cooker all have sheathed heating elements and yet none of these are protected by a residual-current device.

If on a sheathed heating element a pinhole develops, this might allow a small leakage current which can then flow for a long time, particularly if it is on the neutral side, and therefore I doubt if it could be said to comply with the 17th Edition of the Wiring Regulations.

Conversely, refrigerators and freezers are known sometimes to cause nuisance-tripping of an RCD, which can often have rather expensive consequences to a householder.

For this reason, it might be prudent to have separate sockets for these as they are not protected by an RCD.

Edgar H Ring, Middlesex

Source

Electrical and Mechanical Contractor