I should have been a little more precise. What I want to do is remove the need for external earthing and use a triple with one of the cores being the bonding conductor. The screen/armour is on earthed at the control end, the device is also connected to pipework (which is earthed) and sometime...
Can anyone advise me if earthing a spare conductor in a multicore cable will casue me any concerns? The device is a PT having a 4-20mA signal. The screen is isolated at the device end.
Many thanks