My former partner fitted my central heating system with push fit piping and used copper pipe for the all the mains going into the boiler. We had a CORGI gas registered engineer check it and link it to the gas and certified the system. However, a relative of mine has recently noted that none of the radiators or sinks are earthed. I remember my former partner telling me that the push fit plastic piping didn't need to be earthed.
Can anyone tell me what is correct and should I get an electrician or plumber to do whatever needs to be done?