Armoured Cable Question.

[westward10]

You really need the opinion of the second electrician as this may be possible to rectify.

 

[James Farrell]

Here is a picture of the Consumer Unit in the outbuilding. The condemned armoured cable is on the right. The live and neutral go to the 63A Fuse pictured left. The top of the cable cannot be seen but to my horror I saw a short length of earth wire (no more than 2 inches) not clamped in an Earth Terminal but hanging loose in mid air. Could this explain the high ohm reading reported. No other explanation was offered. I was not advised of this unclamped earth wire. There are many empty terminals and the earth cable could easily be clamped. As I am not an electrician I am taking no risks. I hope this assists the many kind electricians who have tried to help me. I am waiting for a visit from a recommended NICEIC Electrician.

 

[James]

We would love to hear the outcome of this,
I am wondering if the outbuilding is on its own TT supply and has its own earth rod.
I am further thinking that the 371 ohms is because the rod is no longer providing a good earth.

A good electrician should be able to explain what the issue is and come up with a solution to fix it.
I suspect that the distribution board in the picture may well need replacing.
the bus bar at the bottom looks heavily corroded and the 63A RCD on the left looks like it has heat damage on its upper right hand side.

 

[westward10]

A rod (TT) is a possible with that rather large conductor at the earth bar.

 

[brianmoooore]

the bus bar at the bottom looks heavily corroded

Looks like it's tinned to me. That would be a first.
No SWA gland or earth connection to the SWA, and a big earth cable that's either a bond (to what?) or to a rod. Has to be TT, surely?

 

[Rockingit]

View attachment 102718

I also suspect a TT / Divorced earth situation, however I'm finding this picture confusing because... Red/Blue conductors would normally indicate an old cols 3c cable yet I see no yellow, and we've two brown lives in the box (B10 and B16) yet only one blue neutral??? We also seem to have three circuit cpc's into the bus bar for four circuit??

 

[James Farrell]

We would love to hear the outcome of this,
I am wondering if the outbuilding is on its own TT supply and has its own earth rod.
I am further thinking that the 371 ohms is because the rod is no longer providing a good earth.

A good electrician should be able to explain what the issue is and come up with a solution to fix it.
I suspect that the distribution board in the picture may well need replacing.
the bus bar at the bottom looks heavily corroded and the 63A RCD on the left looks like it has heat damage on its upper right hand side.

The Consumer Unit is not old and looks like new and there is no corrosion and no heat damage. I really appreciate the kind responses I am getting and possibly only from experienced electricians. I am an elderly home owner and not an electrician and I am trying to understand but this is difficult as I do not follow much of the technical advice. I was told the armoured cable was non compliant and the only reason given was the alleged reading of 371 ohms which means nothing to me. I was told it was dangerous so the reply is turned off. By visual examination I discovered, to my horror, that the earth wire coming from the armoured cable is cut short and in mid air. It is not connected to any one of many earth terminals. I simply wondered if the earth wire is connected if this was likely to produce a safe reading? The electrician was recommending the replacement of the armoured cable. This would be a huge job over a distance of about 20 metres running underground below a concrete floor and a concrete slab adjacent to the outbuilding. It is an awkward sloping site and the cost will be very high but if it is true that it must be replaced to make it safe this is what we will do. If wiring to cut earth cable into an earth terminal makes it safe this will take minutes and minimal cost. I have an NICEIC Registered Electrician visiting in the next week. I will advise on the outcome.

 

[James Farrell]

If he knows his stuff he will fathom it out without us but we would like to know the outcome.

Does this help? The top of the armoured cable is behind the top plate so cannot be seen. The arth cable coming from the armoured cable is cut and can be seen in this picture. As I have stressed several times I am not an Electrician so I struggle with the technical responses so kindly given. I simply wonder if this is why the Electrician said the armoured cable was not compliant and should be replaced which would be at huge cost. I am hoping that once this earth cable is secured in one of many free earth clamps it will then be safe and a safe reading will be produced? Unfortunately the reported unsafe reading of 371 ohms means nothing to me. Questions have been raised about the condition of the consumer unit. It is metal clad and modern and to the untrained eye looks in new condition with no heat marks on any of the fuses as suggested. I hope this clarifies and helps. The good news is that are NICEIC Registered Electrician hopes to visit within a week and I can then report the outcome. Fingers crossed.

 

[UNG]

Do you have a picture of the cable a bit further up and / or a bit of a wider angle so we can see a bit more of how the armoured is installed

 

[James Farrell]

Good Morning Ung - There is no power on in the building following the advice the armoured cable is non-compliant and the serious risks. I used a torch last time which was not ideal. I may be able to use a light on an extension lead from our house and if I can then I ought to be able to get a better picture. I hope to send one later. Thank you for your continuing interest.

 

[Intoelectrics]

I also suspect a TT / Divorced earth situation, however I'm finding this picture confusing because... Red/Blue conductors would normally indicate an old cols 3c cable yet I see no yellow, and we've two brown lives in the box (B10 and B16) yet only one blue neutral??? We also seem to have three circuit cpc's into the bus bar for four circuit??

I agree it looks like a separate TT system. The missing yellow conductor is likely to be the conductor that has been cut back coming from the swa, and left disconnected (the "earth" that James is concerned about). Difficult to see but the missing blue could be terminated in the same terminal as the one shown, but hidden from view in the picture. There appear to be 5 cpc's a pair that appear to be part of a ring or possibly 2 radials also sharing the same breaker in one terminal, one terminated on its own and 2 that share another terminal.

Either way it needs some more investigation and improvement, so will be nice to see what the electrician who's going to take a look has to say about it.

 

[brianmoooore]

I think it's fair to say that something is wrong with this installation that needs investigation and sorting, but there's nothing that we've seen in the thread to suggest that the cable needs replacing.

 

[James Farrell]

I think it's fair to say that something is wrong with this installation that needs investigation and sorting, but there's nothing that we've seen in the thread to suggest that the cable needs replacing.

I PULLED DOWN THE ARMOURED CABLE TO TAKE THESE PICTURES. I HOPE THIS HELPS ALL THE KIND PEOPLE WHO HAVE BEEN TRYING TO HELP ME. Our electrician will be attending in the coming days. The electrician who condemned this cable hoped to replace it and it would be a major job at very high cost. I am hoping our NICEIC Registered Electrician will clamp this loose earth wire and be able to report a safe reading. The other armoured cables got to an external motor, an automatic underground pump and to external lighting. There is only the one incoming supply cable as pictured. This may help those of you who have been trying to help me.

 

[westward10]

There is a few issues here. The cable is not correctly glanded hence the armour is not likely to be effectively earthed. If the cable is readily accessible this can be rectified assuming other tests come back fine. If the electrician decides to maintain the TT system, which we are assuming to be in place then the cable will require correct installation to ensure the armour is earthed and that it is isolated from the TT earth. It probably isn't insurmountable.

 

[James]

That is probably not an earth cable.
it may well be an unused yellow cable.