I've just purchased a data cabinet which according to the manufacturer
needs to be earthed (or grounded).   I am aware that the sides and
roof etc should be connected to a common point but do I then need to
run a seperate cable from this earthing point to the premises
electrical earth?  Is it acceptable to run a length of earth cable to
the earth connector on a wall socket or even the metal back box or
does this cable need to be run back to the main electrical supply
(fuse box).  I've read somewhere that it isn't acceptable to earth the
cabinet just through a mains plug.  Please advise