CPC ring on a radial

[Steve-S]

A great advantage of a final ring circuit is that there is a CPC fed from two ends. If the CPC is broken for any reason the continuity is maintained. So safer for sure. With a radial if the CPC is broken a whole raft of sockets can potentially dangerous. I saw a 4mm radial serving kitchen sockets. I noticed that a CPC wire ran right thru the backboxes not connected to anything in the backbox. So I looked deeper. At the end socket a CPC wire was run back to the CU with the 4mm cable forming a ring. So if the CPC is broken, say at a socket's terminals, there is always a CPC path. Quite responsible I thought. I have only seen this once.

 

[mickegh]

A great advantage of a final ring circuit is that there is a CPC fed from two ends. If the CPC is broken for any reason the continuity is maintained. So safer for sure. With a radial if the CPC is broken a whole raft of sockets can potentially dangerous. I saw a 4mm radial serving kitchen sockets. I noticed that a CPC wire ran right thru the backboxes not connected to anything in the backbox. So I looked deeper. At the end socket a CPC wire was run back to the CU with the 4mm cable forming a ring. So if the CPC is broken, say at a socket's terminals, there is always a CPC path. Quite responsible I thought. I have only seen this once.

I think the term for that is high integrity earthing

It was or is common on circuits feeding equipment that would have inbuilt or standing leakage

A shock hazard could then arise if the single earth is lost

 

[Steve-S]

I think the term for that is high integrity earthing

It was or is common on circuits feeding equipment that would have inbuilt or standing leakage

A shock hazard could then arise if the single earth is lost

Thanks. It is a CPC to be specific, but the same blanket word, earth, is used by us all. On a radial at the socket if two ends of a CPC wire are crimped into a ferrule that is screwed into a sockets CPC terminal then the integrity is far higher as there is no screwed connection to work loose on the CPC wire itself apart from at the breaker at the CU.

On a radial using a CPC wire from the end socket back to the breaker at the CU forming a CPC ring using ferrules or Wagos behind the sockets, gives about the best protection. I use similar on lighting circuits to ensure the integrity of L, N & CPC. Loose screwed connections at say a ceiling rose can mean L, N or CPC drop outs. A CPC drop out creates a dangerous situation.

Americans and our Continental neighbours tend to castigate final ring circuits as they really do not fully understand them. Selective amnesia emerges when it is pointed out to them the high integrity of the CPC and that appliance flexes are protected by a fuse in the plug. Two of the reasons why I am a fan of final rings.

 

[mainline]

Thanks. It is a CPC to be specific, but the same blanket word, earth, is used by us all. On a radial at the socket if two ends of a CPC wire are crimped into a ferrule that is screwed into a sockets CPC terminal then the integrity is far higher as there is no screwed connection to work loose on the CPC wire itself apart from at the breaker at the CU.

Ferrules are intended for use on Class 5 (flexible) and Class 6 (extra-flexible) cables, NOT on solid copper.

Also, testing is far more difficult.

2 x solid core into a single ferrule is a no no.

 

[Steve-S]

Crimped fittings can be used on solid copper conductors. They are used when lugs are needed that require a nut to secure the conductors end. They are also used extensively in control panels with cable numbers at the end of the conductor at a terminal. The crimped end of a conductor prevents the cable numbers from falling off the end.

Two solid conductors into one ferrule is quite common.

 

[mainline]

Crimped fittings can be used on solid copper conductors. They are used when lugs are needed that require a nut to secure the conductors end.

Lugs aren't ferrules, It's easy to tell the difference because they have different names.


A ferrule is a tinned copper sleeve which captures the individual strands of a STRANDED wire. By adding a ferrule to a wire termination, you are essentially giving a stranded conductor the properties of a solid conductor.

View: https://www.youtube.com/watch?v=Ia13o1I6DkM

 

[Steve-S]

A ferrule is a tinned copper sleeve which captures the individual strands of a STRANDED wire. By adding a ferrule to a wire termination, you are essentially giving a stranded conductor the properties of a solid conductor.

View: https://www.youtube.com/watch?v=Ia13o1I6DkM

We know that. Many if these conductors are solid copper. Many with two conductors into one ferrule.

 

[westward10]

We know that. Many if these conductors are solid copper. Many with two conductors into one ferrule.

View attachment 119408

Highly unlikely any of those are solid conductors.

 

[Steve-S]

Highly unlikely any of those are solid conductors.

Many are. I was only looking at it the other day hence the photo.
Lugs are crimped on.