TN-C-S (PEN) RCBOs Discussion

[Rockingit]

You've a TN-C-S (aka PME) system and need to replace that 16mm T&E before worrying about anything else!

 

[Burnmenot]

You've a TN-C-S (aka PME) system and need to replace that 16mm T&E before worrying about anything els

oh ok, is there a problem with that wire?

 

[westward10]

The OP is in Southern Ireland where the TN-C-S is neutralised.

 

[Rockingit]

oh ok, is there a problem with that wire?

You'll need to consult with a reputable electrician to you, but in the U.K. that would not meet our regulations.

 

[Julie.]

oh ok, is there a problem with that wire?

Years ago it would be OK, now it either needs to be replaced by armoured, or surface/contained, depending on how far it goes it may need local protection (such as fuses etc), it also looks a little small - depends on your fuse size but it will be a maximum of 80A

 

[Burnmenot]

You'll need to consult with a reputable electrician to you, but in the U.K. that would not meet our regulations.

I will check, but just out of curiosity, why would they not comply? what is the problem?

 

[Burnmenot]

Years ago it would be OK, now it either needs to be replaced by armoured, or surface/contained, depending on how far it goes it may need local protection (such as fuses etc), it also looks a little small - depends on your fuse size but it will be a maximum of 80A

fuse is 63amp, so you mean that it would have to be on a metal earthed conduit? being concealed in the ESB box?

 

[Soi disant]

the last page of this Hager Tech datasheet mentions that RCCB is not permitted in PEN.

It is just as I suggested in #2. It's talking about PEN conductors - you don't have those in your system.

Your installation is not TN-C, it's TN-C-S. N & E become separate at the service head.

Aso this thread on the IET forum states that an RCD will not work on a PEN system: Electrical Blog - Electrical Advice | Free Electricians Advice Forum - https://electriciansforums.co.uk/discussions/viewtopic/1037/25035

regarding the comment you made about the type, being F perhaps more suitable for some circuits, I'd say that given all the modern equipment we have, (water pump, modern washing machines, dishwashers, and all the IT equipment) maybe even a type B may be more appropriated?

Unlikely - Type F will be OK for the sorts of loads you find in domestic installations, apart from EV charging points, but they're better off separated from the main house installation anyway.

 

[Julie.]

fuse is 63amp, so you mean that it would have to be on a metal earthed conduit? being concealed in the ESB box?

There are multiple options, much depends on how long the run is from the isolator to the cu, and where it is, if it is surface, that is different from concealed; but yes, if it is concealed one option is a metalic conduit.

This work is controlled in Ireland, so you need a fully qualified person to do the work, and they will cover this aspect as much as the actual cu replacement.

 

[Burnmenot]

There are multiple options, much depends on how long the run is from the isolator to the cu, and where it is, if it is surface, that is different from concealed; but yes, if it is concealed one option is a metalic conduit.

This work is controlled in Ireland, so you need a fully qualified person to do the work, and they will cover this aspect as much as the actual cu replacement.

I can see your point, the box was actually smashed to get the meter tails and the service cable, this is 1997... these houses were thrown together in a weekend, way overdue for an upgrade and an in-depth inspection, I will stop here, there are so many other aspects that would not be compliant with the latest regulations... I'm just afraid I'm going to have to rewire the whole house and it will cost me an eye and a leg ;-)

Thanks for your comments