Bonding 😣

[westward10]

In general terms the earthing system is not relevant regarding supplementary bonding.

 

[bennie]

In general terms the earthing system is not relevant regarding supplementary bonding.

Disregard the supplementary bonding question. If services are insulated from earth but still have a main bond in a TNCS system & have accessories that give a pathway surely that would be an issue & would need noting.

 

[Pretty Mouth]

Disregard the supplementary bonding question. If services are insulated from earth but still have a main bond in a TNCS system & have accessories that give a pathway surely that would be an issue & would need noting.

Not quite following you. Is your concern diverted neutral currents, or is it open supply neutral causing a rise in voltage on the earthing system?

 

[bennie]

Not quite following you. Is your concern diverted neutral currents, or is it open supply neutral causing a rise in voltage on the earthing system?

Open supply neutral

 

[Pretty Mouth]

Open supply neutral

Any metalwork connected to the MET could rise in voltage compared to true earth under an open supply neutral fault (on TN-C-S), and that would include the bonded pipework. However, in the property you're inspecting, the pipework is connected to the MET in numerous places, so removing the main bond isn't going to make a real difference.

Either way, the regulations permit the general use of TN-C-S, so it wouldn't be something you would code on an inspection. There are circumstances where TN-C-S is not permitted (eg caravan hookups) in which case you would code it