I have just been involved in a situation where temporary loss of neutral on a TNCS system caused thousands of pounds worth of damage. It seems this loss of neutral situation, either within or outside the installation, is occurring more frequently. SPDs are now commonly fitted but at DBS and generally with a Up in the order of 860v, so giving no protection on loss of neutral in a three-phase and neutral system. Cost benefit analysis across the national spectrum might not support a compulsion but is it time designers should be raising the issue with clients and at least offering a solution. On the other hand, is there a packaged solution?
"Removing the main bonding won't achieve anything at all in an installation with internal conductive service pipes. The pipes throughout the installation would still import PEN voltage from other installations."
But the diverted neutral currents will only flow if the internal conductive pipes are extraneous conductive parts. Electrically isolated metal pipes will not invite external diverted neutral currents at all, or allow them to flow
"Removing the main bonding won't achieve anything at all in an installation with internal conductive service pipes. The pipes throughout the installation would still import PEN voltage from other installations."
But the diverted neutral currents will only flow if the internal conductive pipes are extraneous conductive parts. Electrically isolated metal pipes will not invite external diverted neutral currents at all, or allow them to flow
