Here we go - another meandering discussion

[ban-all-sheds]

522.6.101(v) & 522.6.102

The way that they are written, surface clipped cables which at some point pass through a wall >50mm thick would need RCD protection.

And that unless where they go into the wall is within 150mm of a corner or ceiling, they would also need an accessory there to create the zone running through the wall.


Or, would you argue that as you can see the cable entering the wall, no concealment is taking place?

 

[plugwash]

Or, would you argue that as you can see the cable entering the wall, no concealment is taking place?

Seems like a reasonable argument to me. A cable going straight through a wall and visible on both sides isn't really being concealed by the wall.

On a related note what do you make of trunking that doesn't look like trunking. I would consider the cables inside such trunking to be concealed because it's not obvious what it is.

 

[JohnW2]

Or, would you argue that as you can see the cable entering the wall, no concealment is taking place?

Seems like a reasonable argument to me. A cable going straight through a wall and visible on both sides isn't really being concealed by the wall.

Yes, it seems like a very reasonable common sense argument to me, too. Whether 522.6.101 (which may not understand common sense) would accept that it is 'not concealed' is perhaps not so certain - in as much as the length of cable in the wall clearly is not visible.

On a related note what do you make of trunking that doesn't look like trunking. I would consider the cables inside such trunking to be concealed because it's not obvious what it is.

Yes, (assuming you are not talking about earthed metal trunking) I've often thought about that myself. If one does regard them as 'concealed' (which, again in common sense terms, they essentially are), then there's presumably a big problem - since they are nearly always going to be non-compliant with 522.6.101, even if there is an RCD.

Kind Regards, John

 

[ban-all-sheds]

Technically they are not non-compliant, as they are not concealed in a wall or a partition.

 

[JohnW2]

Technically they are not non-compliant, as they are not concealed in a wall or a partition.

True. As you imply, 522.6.101 would not apply. I wonder if there are any more general regs about protection of cables from mechanical damage that might be invoked I'd have to have a read!)?

Kind Regards, John

 

[ericmark]

It would seem 522.6.101 is only in latest edition so can't comment on that but I did look at warning notice where something does not look to be low voltage. 514.10.1 seems to say nothing is required for 230 volt and I will admit I started to dismantle a lamp in my caravan and could not get a reading with meter yet it worked then realised it was 230vac not 12vdc so meter on wrong range.

Although in a house we assume items are 230vac in a caravan I had clearly assumed wrongly it was all 12vdc except for items clearly marked like fridge, and 13A sockets.

I am sure we have all made mistakes cutting a cable then finding it was an optical fibre was a mistake I made in a car.

Even in so called safe zones I never expected wires to run horizontal between switches on a staggered wall. I was wrong.

But the whole idea to hide cables is rather defeated if we then put labels on them saying danger 230v. In industrial premises we have colours for steam, water, gas and electric but painting items in either the office or home is not really what we want.

However in a office or home there is really no excuse for not using RCD protection and clearly only a valid question for a new installation so I can't think of a situation on a new install where cables will be run in something not looking like electrical and also not RCD protected.

It does raise the point are we really allowed any cables inside conduit or trunking without RCD protection where it is non metallic as mini trunking could just as well contain central heating pipes as cables so there are buried at less than 50mm. Metal earth trunking and conduit is OK but plastic trunking or conduit could just as easy carry water.

I do think common sense must prevail, but to the letter it would seem cables in plastic trunking need RCD protection unless it is marked with BS 5467, BS 6346. BS 6724, BS 7846, BS EN 60702-1 or BS 8436. I stand to be corrected but don't think any of them refer to plastic conduit or trunking.

 

[ban-all-sheds]

Yes, it seems like a very reasonable common sense argument to me, too. Whether 522.6.101 (which may not understand common sense) would accept that it is 'not concealed' is perhaps not so certain - in as much as the length of cable in the wall clearly is not visible.

The regulation talks about cables concealed in a wall or partition, not buried in, or enclosed in, or beneath the surface of etc., and my dictionary defines conceal as to keep from discovery; hide; to keep secret.

 

[JohnW2]

The regulation talks about cables concealed in a wall or partition, not buried in, or enclosed in, or beneath the surface of etc., and my dictionary defines conceal as to keep from discovery; hide; to keep secret.

I essentially agree with you, but I can see scope for discussion. I suppose one of the issues is that, once the cable disappears into the wall, the route is 'hidden' (i.e. one does not necessarily know what direction it goes in), at least when viewed from that side of wall. The common sense view of this situation is pretty clear, and I wouldn't mind arguing on that basis with anyone.

However, if anyone did challenge the common sense view (and argue that it was 'concealed'), then I presume that an RCD alone would not solve the problem, since it would not satisfy any part of 522.6.101.

I can think of at least one situation in my house in which this arises - a pair of ring final cables going from being clipped onto the utility room wall through a hole in the (very thick) wall straight into a socket on the other side of the wall (with both sides not really visible simultaneously from anywhere). Although RCD protected, those cables, if deemed to be 'concealed', would presumably not satisfy any of 522.6.101 - but I'm certainly not losing any sleep over that!

Kind Regards, John

 

[ban-all-sheds]

I essentially agree with you, but I can see scope for discussion. I suppose one of the issues is that, once the cable disappears into the wall, the route is 'hidden' (i.e. one does not necessarily know what direction it goes in), at least when viewed from that side of wall.

Exactly the same concern applies to a cable assumed to be running in a zone created by an accessory.

I can think of at least one situation in my house in which this arises - a pair of ring final cables going from being clipped onto the utility room wall through a hole in the (very thick) wall straight into a socket on the other side of the wall (with both sides not really visible simultaneously from anywhere). Although RCD protected, those cables, if deemed to be 'concealed', would presumably not satisfy any of 522.6.101 - but I'm certainly not losing any sleep over that!

522.6.101(v) states that accessories create a horizontal zone. It does not limit that zone to any particular plane.

 

[JohnW2]

Exactly the same concern applies to a cable assumed to be running in a zone created by an accessory.

Not really. Since the regs define the safe zone created by an accessory, the 'assumption' is that the cable does remain in that safe zone. The regs do not define any safe zone associated with 'a hole in a wall' - so there's no regulatory basis on which to make any assumptions as to where the cable goes after it disappears into the wall.

522.6.101(v) states that accessories create a horizontal zone. It does not limit that zone to any particular plane.

I realise that - so there's no problem from the socket side of the wall. However, as I said the situation is such that one cannot see both sides of the wall at once so, if there were going to be an issue, it's where the cables disappear into a hole in the wall on the non-socket side of the wall.

Kind Regards, John

 

[ban-all-sheds]

Sorry - I didn't read your post properly - I thought you had a socket both sides.

My point was that if you are not happy that a cable visibly entering a wall is not secret and hidden, have an accessory there.

The way that they are written, surface clipped cables which at some point pass through a wall ... would also need an accessory there to create the zone running through the wall.

 

[JohnW2]

It would seem 522.6.101 is only in latest edition so can't comment on that ...

If you have the BRB (i.e. BS7671:2008), rather than the BGB, 522.6.101 and 522.6.102 appear as 522.6.6 and 522.6.7.

However in a office or home there is really no excuse for not using RCD protection and clearly only a valid question for a new installation so I can't think of a situation on a new install where cables will be run in something not looking like electrical and also not RCD protected.
It does raise the point are we really allowed any cables inside conduit or trunking without RCD protection where it is non metallic as mini trunking could just as well contain central heating pipes as cables so there are buried at less than 50mm. Metal earth trunking and conduit is OK but plastic trunking or conduit could just as easy carry water.
I do think common sense must prevail, but to the letter it would seem cables in plastic trunking need RCD protection ...

That's all true in terms of compliance with regulations, but the issue raised by plugwash goes further than the regs in questioning whether complaince with the regulations is adequate in terms of safety. One could easily argue that cables 'hidden' in something disguised to look like skirting board, dado rail or whatever are at least as vulnerable to penetration damage as are those buried <50mm deep in a wall. If the regs took that view (and hence applied similar requirements to these 'concealments' as to buried cables), RCD protection would not be enough, since there would also be a requirement to satisfy the equivalent of 522.6.101 (i.e. earthed sheath, mechanical protection or whatever).

Kind Regards, John

 

[JohnW2]

Sorry - I didn't read your post properly - I thought you had a socket both sides. My point was that if you are not happy that a cable visibly entering a wall is not secret and hidden, have an accessory there.

As I said, I am perfectly happy with it as it is. I did think about an accessory, but I don't need another socket and it would seem crazy to introduce 'unnecessary joints' in the circuit simply to satisfy someone who took a less than common sense view of the regs.

Kind Regards, John