Old rubber and stranded cables

[230volt]

Hi guys,

A customer wants an old re-wireable consumer unit upgraded.

Wiring is extremely old probably 1940's. Of the two power circuits, one is the old rubber cable and one is the old red and black stranded cable.

IR tests show ok L-N L-E N-E.

Problem is the cables have no cpc on the consumer unit side. I'm getting good zs on the sockets which are twin and earth radials on the socket end (so cables must switch via a jb or something under floorboards maybe).

But I have no idea where they are picking up an earth and there is no metal conduit either.

Should I go ahead and change the unit and sign it off even though I cant put the r1+r2 readings in because there is no cpc in the consumer unit?

 

[telectrix]

advise a full rewire. if customer does not want that, then walk away.

 

[Pete999]

advise a full rewire. if customer does not want that, then walk away.

What he said far to many customers think because it works it must be OK not a clue of the dangers

 

[Martin Kerr]

In a lot of older installations ,the CPC was run directly from the main earth Isco , possibly in an unsheathed cable and possibly served a few circuits , just teeing of where ever necessary

 

[Octopus]

Why do they think they need a new CU? New kitchen? new bathroom? extension?

 

[230volt]

It was put on ECR report done from another electrician. He has put r1+r2 readings but i cant see how that is possible with no cpc on the other end.

He told her it needs re-wiring as have I, but she says its too much money.

She wants to get it satisfactory to rent or sell, but I am worried to put my name to it if I do the consumer unit.

 

[Martyc]

I wouldn't do anything I couldn't be comfortable with taking responsibility for, not just electrical but any sort of work. There'll always be someone with no conscience that will do it. Alternatively see if you can pick up the t+e to bring it back to the board

 

[ruston]

Those rubber cables could be in any condition in the building fabric. They may be ok where they are not disturbed.
They could also be bare where they have been.
I would not be changing the board until I was satisfied wit the installation.

 

[Octopus]

It was put on ECR report done from another electrician. He has put r1+r2 readings but i cant see how that is possible with no cpc on the other end.

He told her it needs re-wiring as have I, but she says its too much money.

She wants to get it satisfactory to rent or sell, but I am worried to put my name to it if I do the consumer unit.

What readings do you get?

 

[Deleted member 9648]

It was put on ECR report done from another electrician. He has put r1+r2 readings but i cant see how that is possible with no cpc on the other end.

He told her it needs re-wiring as have I, but she says its too much money.

She wants to get it satisfactory to rent or sell, but I am worried to put my name to it if I do the consumer unit.

It's never going to be satisfactory with rubber cables still in service. It sounds beyond 'updating', rewire or stay clear.

 

[ipf]

It was put on ECR report done from another electrician. He has put r1+r2 readings but i cant see how that is possible with no cpc on the other end.

He told her it needs re-wiring as have I, but she says its too much money.

She wants to get it satisfactory to rent or sell, but I am worried to put my name to it if I do the consumer unit.

If she wants to make money she'll have to spend. Complete rewire for me. If you change the CU you'll have no idea what problems may lie ahead.

 

[Octopus]

Hi guys,

A customer wants an old re-wireable consumer unit upgraded.

Wiring is extremely old probably 1940's. Of the two power circuits, one is the old rubber cable and one is the old red and black stranded cable.

IR tests show ok L-N L-E N-E.

Problem is the cables have no cpc on the consumer unit side. I'm getting good zs on the sockets which are twin and earth radials on the socket end (so cables must switch via a jb or something under floorboards maybe).

But I have no idea where they are picking up an earth and there is no metal conduit either.

Should I go ahead and change the unit and sign it off even though I cant put the r1+r2 readings in because there is no cpc in the consumer unit?

How do you test for IR, L-E and N-E with no earth?

 

[230volt]

Highest zs readings recorded on each circuit

zs 0.82

zs 0.56

 

[230volt]

I tested to the main earth block as somewhere along the line it connects to the sockets i guess

 

[ipf]

How do you test for IR, L-E and N-E with no earth?

...not at the board, obviously:nono: