No earth... Zs and rcd

[james king]

Hello,

Just a quick q....

Went to change a cu and carried out a few test and visual inspections. Found a problam, I think the cable was micc but couldn't tell as none of ends were made off. All cables for all circuits where 2 core NO earth. Zs test on sockets came out with >99kohms....

No I am have a argument with another spark... I think there is no point in installing a rcd cu yet as it wouldn't make any differnce...

What do u all think?

 

[Engineer54]

Hello,

Just a quick q....

Went to change a cu and carried out a few test and visual inspections. Found a problam, I think the cable was micc but couldn't tell as none of ends were made off. All cables for all circuits where 2 core NO earth. Zs test on sockets came out with >99kohms....

No I am have a argument with another spark... I think there is no point in installing a rcd cu yet as it wouldn't make any differnce...

What do u all think?

I think you need a bit more explaining to do here?? lol!!

 

[james king]

No cct have an earth... But they are protected by mcb.

It's tncs supply.

It's a very old installation. The rcd will not work properly if there is no earth present correct?

At the sockets it's just 2 black cables coming through in to the back box..

Same as it enters the cu.

 

[Engineer54]

I was talking about the maybe MICC cable and the ends not being made of?? What about bonding conductors, are they in place??

 

[james king]

Yes 4mm to water. 6mm main earth.... 16mm tails.

No gas in property

 

[Geoffsd]

RCDs don't need a CPC to operate.

You can be the earth.

 

[rmdes]

Socket outlets must be earthed, tell them they have to be rewired if there not interested then don't touch it, it will come back to haunt you when something goes wrong and you've altered a potentially dangerous installation

 

[Deleted member 9648]

Hello,

Just a quick q....

Went to change a cu and carried out a few test and visual inspections. Found a problam, I think the cable was micc but couldn't tell as none of ends were made off. All cables for all circuits where 2 core NO earth. Zs test on sockets came out with >99kohms....

No I am have a argument with another spark... I think there is no point in installing a rcd cu yet as it wouldn't make any differnce...

What do u all think?

How can you not tell an MICC FFS?


If nothing at all is earthed.....either sort it and then change the cu, or dont touch it at all.

 

[tigerpaul]

If its MICC, then the sheath is the earth.
RCD's will make a difference!

 

[Sintra]

Think there is a bigger problem than just bunging an RCD on it. This installation needs to be checked properly.

 

[kingeri]

Are the sheaths terminated/connected to the earthing terminals in the CU/accessories?

 

[Clive P]

Hi,

Don't quite understand the 'ends not made off'. If all of the circuits are wired in micc with the glands earthed to the backbox, then you have your earthing and the two black wires are the line and neutral sleeved as they should be ' black' with an indication as to which is live and which is neutral. A lot of older installations would of been done like this, before the 'earthed pot' arrived on the scene. I would retest and check for your continuity, could be a loose gland on one of the backboxes, I can't see that they wouldn't have been glanded.

Regards.

 

[MDJ]

I expect the DB end of the system has just the phase conductors into the board and the gland not earthed at that point, if an earth was connected to that gland I bet it would all be fine, I love micc, wish my house had it, it would last for 70 years haha

 

[GLENNSPARK]

How can you not tell an MICC FFS?


If nothing at all is earthed.....either sort it and then change the cu, or dont touch it at all.

aye and upgrade that bondin n all....caus as it stands its an instant (2)...

 

[Engineer54]

I expect the DB end of the system has just the phase conductors into the board and the gland not earthed at that point, if an earth was connected to that gland I bet it would all be fine, I love micc, wish my house had it, it would last for 70 years haha

And then some!! lol!!