I'm not sure if the Regs allowed separately bare earths.

[sham]

I've been on this job to do an inspection before fitting a new RCD OR RCBO board. In most of my career until now the CPC is inside the T+E cable. This property has a separate CPC all through out the building. Only where there has been modifications, modern wiring has been used. If I can prove the ZS is good, is it ok to connect to this system. It's seems to be mainly the lighting that is wired in single sheathed cable which has been ran in conduit. I am hoping if anyone has any information regarding the regs about separate bare earth running through the property. There is a risk of borrowed neutrals if changing to an rcd or rcbo board. The customer does not want a Rewire but wants spots fitted and sockets moving. I have convinced him to change the board, now I am worried about nuisance tripping. However if you could advice about the earth mainly would be a great help. Personally I feel the wiring was good for it's day.

 

[Andy78]

Where does the earth originate ? In my experience separate bare cpcs like this are often connected to lead water pipes as a means of earthing.

 

[MFS Electrical]

Sticking my neck out here I’d say of course Because regs are not retrospective as long as all the tests are good and you comply with the current regs regarding RCDs etc I don’t really see it as any different to connecting to Red and black PVC.

 

[MFS Electrical]

Where does the earth originate ? In my experience separate bare cpcs like this are often connected to lead water pipes as a means of earthing.

Never actually seen that but good point. As long as the earth does actually come from the CU/fusebox and not the water pipe and all of the tests are ok I don’t see a problem.

Obviously upgrading the bonding as well when replacing the board

 

[Andy78]

Never actually seen that but good point. Obviously upgrading the bonding when replacing the board

Seen it most where rubber twin (no cpc) was used, either VIR twin or TRS. Bare cpc was often taken from a lead pipe, either soldered on or clamped on, and taken individually to sockets.

 

[sham]

Where does the earth originate ? In my experience separate bare cpcs like this are often connected to lead water pipes as a means of earthing.

It appears to be connected to the earth on the board which is fed by TN-S

 

[MFS Electrical]

It appears to be connected to the earth on the board which is fed by TN-S

I’d be looking to just confirm that but I really don’t think there’s a problem...

 

[sham]

Seen it most where rubber twin (no cpc) was used, either VIR twin or TRS. Bare cpc was often taken from a lead pipe, either soldered on or clamped on, and taken individually to sockets.

Found this in the ceiling also was interfering just with my continuity test, traced the wire back to this . 1mm cable connected and two lead cables of 2.5. It was a stressful day lifting floor boards.

 

[MFS Electrical]

Found this in the ceiling also was interfering just with my continuity test, traced the wire back to this . 1mm cable connected and two lead cables of 2.5. It was a stressful day lifting floor boards.

View attachment 44941

Is that the guts of an old thorn 8ft brings me back to the first few months of my apprenticeship taking down these old lumps and replacing them with 6fts and I mean lumps just about a 2 man lift to get the bloody thing down

 

[sham]

I’d be looking to just confirm that but I really don’t think there’s a problem...

Because there are bare earthed in the board I have come to that conclusion, but to no for sure, there are so many limitations

 

[MFS Electrical]

Because there are bare earthed in the board I have come to that conclusion, but to no for sure, there are so many limitations

Are the main gas and water bonded?

 

[7029 dave]

It appears to be connected to the earth on the board which is fed by TN-S

Time gone by, bare earth was used for bonding services, and used as main earth lead.

 

[sham]

Is that the guts of an old thorn 8ft brings me back to the first few months of my apprenticeship taking down these old lumps and replacing them with 6fts and I mean lumps just about a 2 man lift to get the bloody thing down

Well, this is under the upstairs floor board and two cables come out, they felt cold and are metal, never seen anything like it. These metal cables go to the end of a roof end, loft. (It is a bungalow) they end up in junction boxes that go nowhere else. Diconnected

 

[MFS Electrical]

I’d disconnect the bonding and the bare earths from the board and do an R2 on the bare earth from the end at the board to ensure its complete and then again at the bit your going to connect into and to the board itself and then the pipes themselves just to rule out that the bare earth was coming from elsewhere I reckon if you do that you’ve pretty much proved beyond reasonable doubt that the earth is suitable and actually coming from the CU and not the pipes or anywhere else.

 

[MFS Electrical]

Well, this is under the upstairs floor board and two cables come out, they felt cold and are metal, never seen anything like it. These metal cables go to the end of a roof end, loft. (It is a bungalow) they end up in junction boxes that go nowhere else. Diconnected

Old lead cables probably wonderful stuff the rest of the cables in the house aren’t lead are they?

 

[sham]

Are the main gas and water bonded?

The water pipe by sink is bonded to the Earth bar but not to main stop tap. Nobody knows where stopcock is inside.
The Gas, I will investigate tommorrow, but boiler is cross bonded

 

[sham]

Are the main gas and water bonded?

The water pipe by sink is bonded to the Earth bar but not to main stop tap. Nobody knows where stopcock is inside.
The Gas, I will investigate tommorrow, but boiler is cross bonded

 

[MFS Electrical]

The water pipe by sink is bonded to the Earth bar but not to main stop tap. Nobody knows where stopcock is inside.
The Gas, I will investigate tommorrow, but boiler is cross bonded

I’m just wondering if the bare earth leaves the board swings by the pipes and then on to the circuits

 

[sham]

I’m just wondering if the bare earth leaves the board swings by the pipes and then on to the circuits

Every thing is boarded carpeted and plastered.

 

[MFS Electrical]

Seen it most where rubber twin (no cpc) was used, either VIR twin or TRS. Bare cpc was often taken from a lead pipe, either soldered on or clamped on, and taken individually to sockets.

What the h**l is TRS by the way?

 

[MFS Electrical]

Every thing is boarded carpeted and plastered.

I know you can’t physically trace it but if you test it like I say above you should be all good

 

[SparkyChick]

Tough Rubber Sheathed maybe?

 

[MFS Electrical]

Tough Rubber Sheathed maybe?

Don’t think I’ve ever seen that

 

[freddo]

and two lead cables of 2.5.

2.5mm Lead cables?!?

Don’t think I’ve ever seen that

There's many miles of the stuff still in use in Devon, some in terrible condition. Have some old magazines here that stated a safe working life of only 10-15 years

 

[sham]

Old lead cables probably wonderful stuff the rest of the cables in the house aren’t lead are they?

Now you mention it, how would I know if the lighting cables are lead. I just assumed they are copper. The system is mixed. The sockets are wired with stranded cables here and there, as long with the lights. There has been changed since.

 

[SparkyChick]

2.5mm Lead cables?!?

There's many miles of the stuff still in use in Devon, some in terrible condition. Have some old magazines here that stated a safe working life of only 10-15 years

Am I right in thinking freddo TRS is the thick black rubber sheathed stuff that's a real nightmare to cut?

And VIR is the cloth/cotton covered singles?

 

[MFS Electrical]

2.5mm Lead cables?!?

There's many miles of the stuff still in use in Devon, some in terrible condition. Have some old magazines here that stated a safe working life of only 10-15 years

Horrible stuff i remember a few years ago attending a fault that was caused by the lead sheath being compressed and nicking the cores couldn’t for the life of me figure out what it was as someone had replace the CU and Extended the lead with PVC

 

[SparkyChick]

Now you mention it, how would I know if the lighting cables are lead. I just assumed they are copper. The system is mixed. The sockets are wired with stranded cables here and there, as long with the lights. There has been changed since.

Lead cables have an outer sheath of lead.

If the conductors of the cables you're looking at appear silver, they are either tinned copper or if they feel very flexible but break easily, they could be aluminium.

 

[sham]

2.5mm Lead cables?!?

There's many miles of the stuff still in use in Devon, some in terrible condition. Have some old magazines here that stated a safe working life of only 10-15 years

Metal, I assumed they were frozen, cold.

 

[sham]

Horrible stuff i remember a few years ago attending a fault that was caused by the lead sheath being compressed and nicking the cores couldn’t for the life of me figure out what it was as someone had replace the CU and Extended the lead with PVC

It really messed up my continuity test.

 

[MFS Electrical]

Metal, I assumed they were frozen, cold.

Yeah if they felt frozen they’d be lead sheathed just wondering if the rest of the wiring was the same don’t think aluminium was really ever a viable conductor here except in SWAs but @SparkyChick is right on how to identify it

 

[sham]

Lead cables have an outer sheath of lead.

If the conductors of the cables you're looking at appear silver, they are either tinned copper or if they feel very flexible but break easily, they could be aluminium.

They are not weak, but because I scraped the bare end because it looked dirty it seemed silver underneath, is this an issue ?

 

[sham]

Lead cables have an outer sheath of lead.

If the conductors of the cables you're looking at appear silver, they are either tinned copper or if they feel very flexible but break easily, they could be aluminium.

They are not weak, but because I scraped the bare end because it looked dirty it seemed silver underneath, is this an issue ?

Yeah if they felt frozen they’d be lead sheathed just wondering if the rest of the wiring was the same don’t think aluminium was really ever a viable conductor here except in SWAs but @SparkyChick is right on how to identify it

All seem disconnected. That is the only lead I found.

 

[SparkyChick]

They are not weak, but because I scraped the bare end because it looked dirty it seemed silver underneath, is this an issue ?

It's hard to say from a distance.

It all depends on what you scraped.

 

[MFS Electrical]

Am I right in thinking freddo TRS is the thick black rubber sheathed stuff that's a real nightmare to cut?

And VIR is the cloth/cotton covered singles?

Not too sure on the TRS as I’ve never seen it but VIR is definitely the cloth cotton covered rubber kinda looks a bit like skanky iron flex but most of it that you’ve probably encountered has had the rubber completely disintegrate and fall off I worked for the council in my area years ago and encountered it in the town hall all crispy and horrid caused problems after problems but as far as I’m aware is still in service now because they didn’t want to pay to rewire it

 

[SparkyChick]

To add... aluminium cable is a nightmare. I've done a couple of jobs where the conductors have been nicely dressed into the back box, but just taking the socket off has snapped them.

I think the aluminium becomes work hardened by merely bending it (like copper will) but more quicker. Hard metal normally means brittle metal, so you have to be very careful working with it.

 

[MFS Electrical]

To add... aluminium cable is a nightmare. I've done a couple of jobs where the conductors have been nicely dressed into the back box, but just taking the socket off has snapped them.

I think the aluminium becomes work hardened by merely bending it (like copper will) but more quicker. Hard metal normally means brittle metal, so you have to be very careful working with it.

And if the sheath is damaged or there is any damp the Aluminium will sort of corrode (oxidise)and significantly reduce the conductivity and mechanical strength

 

[sham]

It's hard to say from a distance.

It all depends on what you scraped.

The wiring seems the old singles that go through galvanised conduits, the wires have grey sheath followed by red insulated wire. The red insulation seems good. The nuetrals outer sheath appears darker, could say black or like that because it's old followed by black insulation then bare wire. The cores are stranded and seem strong. And thicker than 1.5 mm.

 

[SparkyChick]

The wiring seems the old singles that go through galvanised conduits, the wires have grey sheath followed by red insulated wire. The red insulation seems good. The nuetrals outer sheath appears darker, could say black or like that because it's old followed by black insulation then bare wire. The cores are stranded and seem strong. And thicker than 1.5 mm.

Sounds to me like double insulated singles. Imperial size. The conductor is most likely to be tinned copper.

 

[sham]

Sounds to me like double insulated singles. Imperial size. The conductor is most likely to be tinned copper.

Is this an issue.

 

[SparkyChick]

Is this an issue.

Providing the cables check out fine then no, it shouldn't be.

Sounds like your biggest issue is potentially the earthing.

 

[westward10]

Aluminium conductors in this country is common for distribution cables but for small scale stuff it became popular when copper prices rocketed in the 70s/80s and yes SC I have some off cuts. BICC (British Insulated Calender Cables) is the most common manufacturer to be found and it can be hard to spot as the aluminium conductor was copper clad so it appears to be copper. The chances of a lead sheathed cabled produced for UK use having aluminium conductors is less than zero although they may appear to be as they will be tinned copper.

 

[SparkyChick]

All the ali stuff I've worked on here has been plain vanilla aluminium, didn't realise there was a copper clad version.

I remember seeing them putting new sub-mains in when one of my schools was being renovated. Big honking 3P+N SWA cables with quarter segments of aluminium in those oh so lovely colours.

 

[MFS Electrical]

Bring back red yellow and blue

 

[westward10]

Copper clad was generally restricted to the small scale T&E cables, it was made by placing an aluminium bar in a copper tube and stretching it to produce the conductor. Often only realised today when the conductor keeps breaking, common sizes were 1.5 solid and 4.0 stranded.

 

[freddo]

I have seen a few lengths of copper clad aluminium, I have some 7/.029 here somewhere. I have only once seen a house wired with solid aluminium cables, horrible stuff just breaks off when disturbed.

 

[westward10]

Some more of my samples from the garage SC, this is 1.5 copper clad aluminium T&E.

 

[westward10]

I have seen a few lengths of copper clad aluminium, I have some 7/.029 here somewhere. I have only once seen a house wired with solid aluminium cables, horrible stuff just breaks off when disturbed.

I suspect the 7/.029 is actually 4.0mm as I am pretty sure although not certain it was never produced under imperial sizes.

 

[sham]

Do I need to be careful is I was to do live ZS test as the earth is all over the place

 

[MFS Electrical]

I suspect the 7/.029 is actually 4.0mm as I am pretty sure although not certain it was never produced under imperial sizes.

I have not a clue what that means imperial is complete gibberish to me