Safe Zones, 230yr Old Cottage

[GPHouse]

Hi

New here and hoping someone may be able to provide some advice. I'm not a novice from a wiring perspective but from a regs perspective I haven't got a clue.

I will also be engaging an electrician for a load of works but need to do some prep work as part of renovation and route planning.

I have a 230yr old cottage with rubble walls and lime plaster (60mm) which is a little fragile. There is some existing working circa 10yrs old running ring mains to a consumer unit.

I am currently looking at adding some sockets and in part of the building I am doing some work... BUT....

Given non standard joist sizes and the fragility of the plaster I cant run new cabling though the flooring, or in the traditional safe zones (from the roof down) without compromising the structure or the original features / plaster.

Are Safe zones a recommendation or a requirement when working with LABC?

There is a natural void behind the skirting - If a method of trunking cables behind the skirting, and affixing the skirting in a regularized (and obvious way) would this be acceptable as risk mitigation? If so could I get away with 1" rectangular trunking (plastic as lime and metal dont play well) or would I need to go for stainless steel conduit?


Any help gratefully received!

G

 

[hightower]

Zones are a requirement, not a recommendation. There are ways around them, however, most useful probably being the use of earthed metal containment such as steel conduit or SWA cable.

 

[GPHouse]

Thanks. So from a zone perspective, If I ran stainless conduit behind the skirting with clear, regular affixings for the skirting in that region to minimise risk (skirting will have to be attached to wooden wedges into the rubble wall), Do you think this would be satisfactory ?

Sockets and Switches would then be vertical from the steel conduit.

 

[Andy78]

I would engage an electrician at the earliest possible juncture. They will advise as to potential routes for cables, the level of involvement they are willing to have you partake in, and other regulations queries.

In this instance a first hand view of the situation will be invaluable, but be braced for disturbance of the plaster as this may be unavoidable.

 

[westward10]

Zones are a requirement, not a recommendation. There are ways around them, however, most useful probably being the use of earthed metal containment such as steel conduit or SWA cable.

Can you still get cables to BS8346 which incorporates it's own aluminium sheath suitable for use without additional protection or containment.

 

[Andy78]

Can you still get cables to BS8346 which incorporates it's own aluminium sheath suitable for use without additional protection or containment.

I believe so. Never used any myself though, or had occasion to.

 

[westward10]

I believe so. Never used any myself though, or had occasion to.

Just wondered, I've never used or seen it, but seems a good solution.

 

[Lucien Nunes]

And another cable choice that might solve some of the problems is MICC, with LSZH oversheath so that it can be run in contact with lime plaster. Requires bulkier terminations than BS8346 but in some cases the cable itself will be smaller.

 

[GPHouse]

Thanks. Looked at Pyro/MICC as both an intra mortar and external option but didnt look at the LSZH sheath options. Pricey.

I was trying to avoid visible cables and was hitting a bit of a wall re the reactions between lime and Copper.

The ALU option would be a risk with lime as it's particularly susceptable to alkaline environment and degrades rapidly.

 

[westward10]

BS8346 cables have an overall non metal sheath.

 

[Pete999]

Hi G

Probably opening up for some abuse here in my response, any electrical work in a dwelling of that age, is, in my opinion, some may disagree, is a skill in it's own right, not the sort of work for your average House Basher.

Whilst I applaud you for suggesting you do some of the work yourself to help with the costing is laudable, it really isn't as simple as running conduit for the Electrician, the job needs care and consideration, some Guys have suggested using various sorts of cable, all good advice, my advice would be engage the Electrician at the onset of the work, and choose the Electrician wisely, don't go for the cheapest and quickest as these types usually cock up the work, and you could be faced with expensive rewiring, is the building listed? you may find if the answer is yes certain restrictions applied, in any case good luck, let us know how you get on. My tin hat and flak jacket are firmly in place.

 

[Midwest]

Concur with Pete re DIY electrical work.

That aside, have you considered installing a stud wall in front of you actual finished surface, not withstanding any building regs re these of old walls, sufficient depth to add your additional sockets. Then you would have a suitable smooth wall finish, unless that's against the projects strategic/planned aims?

 

[yellowvanman]

Just wondered, I've never used or seen it, but seems a good solution.

Used it a number of times on really old buildings, I'd recommend. Not too difficult to use and no overly expensive.

Only limitation is that the MCB should be more than a 32A Type B. Not really a limitation in domestic.

 

[markythesparky]

My brother lives in a tudor house in kent and although there are very small voids under some of the floor boards they are not continuous and cannot be relied upon for cable routes. as for coming down walls, none of the cables are concealed but run next to the beams and then painted the same colour. this actually is surprisingly invisible! there is not much in the way of options for this type of property I'm afraid.