3 Legged Ring ???

[YT1969]

Hi guys, I have found a 3 legged ring main during an EICR, it’s 2.5mm TnE with a 16A MCB & no RCD Protection. As it measures a S a ring between any 2 of the 3 legs, can a 32A RCBO be Installed or should it remain at 16A ?

 

[Dartlec]

Hi guys, I have found a 3 legged ring main during an EICR, it’s 2.5mm TnE with a 16A MCB & no RCD Protection. As it measures a S a ring between any 2 of the 3 legs, can a 32A RCBO be Installed or should it remain at 16A ?

That doesn't sound like a correctly wired Ring Final Circuit if you are getting continuity between any 2 out of the 3 legs. Are the readings similar on each pair of legs and do they tally with the expected length of the circuit? R1+R2 also?

There is no such thing as a '3 legged ring', so you'd need to track down where the legs go and fully understand what's going on before increasing the protection. It may be a RFC but with a radial also installed to one point (for some weird reason). Or there may be a cable or wiring fault that is giving you an inaccurate continuity. Were the IR readings OK?

It may well have been placed on a 16A for a good reason, because of previous testing - or because the installer had no idea what he was doing...

 

[GBDamo]

Are you on the Isle of man?

Sounds iffy, would be wanting to break this down and know what and where every leg feeds.

 

[YT1969]

That doesn't sound like a correctly wired Ring Final Circuit if you are getting continuity between any 2 out of the 3 legs. Are the readings similar on each pair of legs and do they tally with the expected length of the circuit? R1+R2 also?

There is no such thing as a '3 legged ring', so you'd need to track down where the legs go and fully understand what's going on before increasing the protection. It may be a RFC but with a radial also installed to one point (for some weird reason). Or there may be a cable or wiring fault that is giving you an inaccurate continuity. Were the IR readings OK?

It may well have been placed on a 16A for a good reason, because of previous testing - or because the installer had no idea what he was doing...

Dartlec - great response , thanks very much