Minor electrical work/general house question

hatt55

After a bit of advice/reassurance. This probably highlights my lack of knowledge about house construction but I’m still quite new to all this!

Essentially I moved in to a terraced house about 6 months ago and had an electrical safety (can’t remember the exact term) done soon afterwards. This highlighted that everything was fine except the circuit with the downstairs sockets on. The electrician has suggested cutting off part of the circuit and running new cabling to the back of the house, through the kitchen and to the back to bypass the section of the circuit where the fault has been identified. They have suggested this approach as we don’t know where the current cabling goes, so this avoids taking up kitchen units and flooring etc. and uses short sections of trunking. At this stage I’m not too bothered about the aesthetics so trunking is fine.

They have explained that the approach would involve drilling and running the cable diagonally through the quite thick wall which separates the kitchen and utility room at the back of the house. Part of this wall is a redundant chimney breast, and there are a few slightly strange patches of damp/bubbling paint on the wall and in the doorframe. The boiler is mounted at head height on the utility room side, so there is water pipework in the vicinity but not immediately adjacent to any of the damp bits (I say ‘damp’ – that’s the easiest way to describe them).

This is something that I need to look into in the longer term, but at the moment I just want to get this bit of the electrical work sorted. So my question is, are there any potential issues with drilling through the wall that has these damp patches in? My (entirely non expert) opinion is that it isn’t rising damp and is instead associated with the chimney in some way. They’re isolated patches and as such don’t have an obvious source, but they’re also not at the bottom of the wall where the cable would go. What I don’t want to do is introduce any other problems by putting a hole through the wall I suppose.

I feel almost slightly foolish for asking this question, because there must be holes through loads of the walls in a house. But there is seemingly something not quite right with this dividing wall between the kitchen and utility and I don’t want to make anything worse.

Any advice appreciated!

TheBiggerPicture

My husband is an electrician, says... If you still want power to the sockets in question, assuming this is a ring circuit you can always disconnect one of the cables at the fuse box and at the end where the fault is, and down rate the breaker size, if you dont want to install new cabling and can manage on 16 amp of current.
Its quite common for damp on chimney breasts - most probably rain coming in chimney pot - you may require a chimney pot cap and it should dry out naturally. If you do get the cabling in trunking at the bottom of a damp wall, its quite safe as itll be inside the trunking, assuming you dont have water litterally running down the walls - damp patches are fine.

TheBiggerPicture

P.s. my husbsnd said get an electrician to do as suggested above, would be far cheaper, then fix the damp problem

Heedtheadvice

Hmmmmm.
Did you give your hubby full information?

There is nothing wrong with having a star rather than ring circuit and derating it down to 16A ......but for the whole of the downstairs? Presuming it includes the kitchen/utility area, at times 16amps might not be enough current carrying capacity.
Most of the time probably ok until the kettle, toaster, possibly a small heater, vacuum cleaner or iron are all on at the same time. That could be 12+4+6+++ already exceeds 16A.

Calculations do allow for diversity (likelyhood of appliances being on at the same time) but if the above presumptions about areas fed by the circuit there could often be more than 16A demanded with consequential tripping. Not good design practice.

Far better to reinstate as a ring circuit.

hatt55

Thanks all.

It's just damp patches, and infact having posted this I went and had another look - for the most part the cabling will be away from them. I was just concerned that putting a hole through the wall might somehow makes things worse. Presumably that depends on the source of the damp; I'm not 100% sure its due to the chimney, but it does sort of make sense. So fixing that is another thing on the list!

The utility room has the washing machine, fridge freezer and microwave in it, as well as occassional use of the kettle and a dehumidifier. So its a well used circuit that I'd like to have working properly.