I'm not sure what their thinking was when the policy was created but I doubt it was electrical safety. As it meant not having to consider PE/supplementary earth points at home locations it made my life easier. Our program has grown and as we are now getting more patients with access problems having to come in to dialyse the policy is being reviewed. From the four responses I've had so far all allow patients to treat at home on a line.
We have a policy that allows HHD patients to dialyse with a CVC, as we have been fitting equipotential sockets at our home installations to connect up the machine, RO and chair (where required).
The earth cable is taken back to the distribution board, wherever possible.
We are using CE sockets (16A) for machine and RO for discrimination.
The electrical installation is tested to BS 6061 as normal, with 30mA RCD feeding the dialysis equipment.