How would you repair this?

[RF Lighting]

That Lower Grey Cable looks like it's mauled quite badly. Sounds a bit daft given some insulation is stripped back to bare minimum but I think I'd have to do an IR Test on individual circuits to determine if it's safe. Ideally replace, Self amalgamating tape might help as would a type of Wrap around Heat Shrink Tape but it could be a Fire Hazard or have Nuisance tripping in future. Is that a Cooker circuit, sockets and Lighting or is there anything else?

The building needs to be sealed better from Rodent infestation. They must have insurance?

I’m not sure what the lower cable is, I haven’t invested much time in this. The large cable is the cooker, and the other cable is a lighting feed.

A good section of the building has previously been rewired in pyro following previous rodent damage. Unfortunately it’s virtually impossible to keep rodents out of the void. It’s a wooden scout hut on the edge of a park

 

[JohnW2]

Now here’s the problem. There are only 2 or 3 mini traps to the floor void for fishing cables through etc. The vast majority of the building is plywood boarding nailed on top of the floor boards, and then carpet / Lino glued to the plywood. I’ll try my best to look under the floor with mirrors etc.

I suspected that might be the case. Maybe an 'endoscope'/'snake camera'/whatever would help?

However, it's definitely a problem, with no particularly practical/realistic solution. In the case of the rodent-damaged cable I found in my house (as illustrated above), I did lift a small number of boards in the vicinity, and found no other similar damage. However, to have inspected all of the underfloor cables throughout my (very large) house was essentially 'unthinkable', so I just repaired the damage I had found and ever since (many years) have 'lived with' knowledge of the fact that there might be similar damage to other cables in the house (despite IR testing of all circuits being OK). One may feel that the situation is different in a 'public building' but, certainly in the case of my own house, I don't think there was any other realistic option.

Good luck.

Kind Regards, John

 

[JohnW2]

... but I think I'd have to do an IR Test on individual circuits to determine if it's safe.

As I said (e.g. per the rodent-damaged cable I illustrated above), IR testing is not an effective way to identify such damage or to confirm 'that it is safe', and hence can easily result in a feeling of false confidence/reassurance. Unfortunately, nothing other than visual inspection of all cables can give true reassurance - and, as I've said, that certainly wouldn't be done in the course of a standard EICR inspection.

Kind Regards, John

 

[JohnW2]

A good section of the building has previously been rewired in pyro following previous rodent damage.

As a matter of interest, how resistant is pyro to the attention of rodents? I've certainly seen very significant rodent damage to 'minibore' CH pipework (albeit falling short of 'penetration'). If I wanted to be 'sure', I think I'd have to use SWA or steel conduit!

Kind Regards, John

 

[RF Lighting]

As a matter of interest, how resistant is pyro to the attention of rodents? I've certainly seen very significant rodent damage to 'minibore' CH pipework (albeit falling short of 'penetration'). If I wanted to be 'sure', I think I'd have to use SWA or steel conduit!

Kind Regards, John

It seems to have been successful. It’s been in a good few years, and had it sustained any damage we’d certainly know about it by now

 

[DetlefSchmitz]

This seems rather knee jerk. No one is suggesting that they have any intention to leave their building unsafe. That is why I’m there installing a new fire alarm in the first place.

Yeah, I have a history with them. It involves them stating locally that they would not accept disabled people (Asperger's) as cubs.

 

[333rocky333]

As a matter of interest, how resistant is pyro to the attention of rodents? I've certainly seen very significant rodent damage to 'minibore' CH pipework (albeit falling short of 'penetration'). If I wanted to be 'sure', I think I'd have to use SWA or steel conduit!

Kind Regards, John

I heard once that the French add a chemical in there cables to repel rodents

 

[sparkwright]

I’ve been to start a job today and upon lifting a piece of floor, I’ve found some gnawed cables.

I am on this job to install a new fire alarm system. I have some new cabling to run very near this location and for my own protection want to repair the cabling before I start work near it.

The job is in a scout and guide hut, so funds are limited as always.

Obviously replacing the cable would be the ideal situation but is not really practicable. I realise there may well be other damage elsewhere and I will be taking precautions to keep myself safe.

What would you do in this situation?


View attachment 202446

Presumably you don't want to spend much time on it.

Besides some form of taping/sleeving the cables, you could then fit a plastic enclosure or trunking over the lot, if only to hide and protect the 'repair'.

 

[RF Lighting]

I’ve had a chat today with the chap from the scout hut and he’s obviously keen to get this repaired, but without spending more money than necessary as there are plans for a major refurbishment in 5 to 10 years when this can be properly resolved for good.

Here’s what I’m up against in regards to access below the floor

I’ve had a look around with the mirror today and I honestly can’t see any further damage as all the cables look to be running over the dwarf walls and are a bit more up and out the way.

I think this has been used as a route from the main hall in to the store room for the rodents which has had all the food removed and bait put down some time previously.

The bottom cable in the original picture has sustained more damage than the others. Perhaps because it’s on the neutral side?

 

[JohnW2]

... The vast majority of the building is plywood boarding nailed on top of the floor boards, and then carpet / Lino glued to the plywood.

.... Unfortunately it’s virtually impossible to keep rodents out of the void. It’s a wooden scout hut on the edge of a park

Here’s what I’m up against in regards to access below the floor

Hmmmm!

For the future reference of someone designing such a place (or, at least, it's electrical installation) is it perhaps the case that, with such a building, in such a location and with the prospects of that sort of flooring, even though having cables under the floor might be the simplest and cheapest initial approach, it may well not be the wisest?? Traditionally, one might expect wiring to be in surface-mounted conduit in such a building.

Kind Regards, John

 

[RF Lighting]

Hmmmm!

For the future reference of someone designing such a place (or, at least, it's electrical installation) is it perhaps the case that, with such a building, in such a location and with the prospects of that sort of flooring, even though having cables under the floor might be the simplest and cheapest initial approach, it may well not be the wisest?? Traditionally, one might expect wiring to be in surface-mounted conduit in such a building.

Kind Regards, John

Yes I agree!

The hut was built in the 50s, extended in the 60s and had a bit of a refurb around 2000. The electrical installation very much reflects the evolution of the building with things like only a single RCBO for the sockets, and unfortunately we are at the moment stuck with it! I was involved with the refurb of the toilets about 10 years ago which was all wired in steel tube and as far as I know has never had an issue.

Having spent a lot more time working on big commercial projects, and if I’m still involved in the next phase, surface steel trunking and tube will definitely be the preferred option.

 

[bernardgreen]

As a matter of interest, how resistant is pyro to the attention of rodents?

They have been known to attack it.

Why they do it is explained HERE

I recall that they may be less interested in lead pipes, The Austrian PTT found that old sheathed telephone cables suffered less rodent damage than the plastic sheathed cable used to replace the ancient lead cables. These were the main cables installed along the walls of the city sewer system which was home to thousands of rats.

 

[conny]

That was a very interesting read.
Thanks Bernard.

 

[bernardgreen]

That was a very interesting read.

Something to get one's teeth into......?

 

[blup]

No, your not supposed to dismantle the installation for an EICR, let alone the building.

But to the extent that the building was already dismantled, by lifting the floorboards, would an EICR not have to address this?

Blup