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Topic Title: Why do mice\rats chew cable.What is best method of prevention.
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Created On: 07 February 2013 09:23 PM
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 07 February 2013 09:23 PM
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antric2

Posts: 1148
Joined: 20 October 2006

Evening all,
What draws vermin to chew on twin and earth and alarm and phone cable.
What is the most effective preventative method any of you have used especially when there are anumber of cables grouped together.
Regards
Antric
 07 February 2013 09:35 PM
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AJJewsbury

Posts: 12774
Joined: 13 August 2003

I was told they like the texture of the PVC to sharpen their teeth on - so they're not really bothered that it doesn't have any nutritional value or taste particularly good. A bit of steel trunking or conduit would seem like a solution - but make sure there aren't any holes - to make sure it doesn't turn into a cosy mouse nest box!

- Andy.
 07 February 2013 10:02 PM
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slittle

Posts: 3674
Joined: 22 November 2007

Probably the best method is plenty of bait, however this does provide an increased risk for us sparkies if we have to work near it.

I hear the ultrasonic units work quite well too.

Bear in mind if you are considering trunking or conduit that it needs to be done properly, a mouse will get through a hole about the size of a biro pen and as Andy has said, once in there they will spend their time chewing.


Stu
 07 February 2013 10:03 PM
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eclectica

Posts: 63
Joined: 16 August 2010

I'm not sure what draws vermin to chew on T&E cables - maybe they get bored and need some excitement

Seriously though, it is a total nightmare especially in rural areas and properties with old hollow middle stone walls set directly on the earth - as soon as the weather turns cold, in come the mice.

Trying to block up any entrance holes from outside is obviously the first thing, and then bait around the outside of the house (bait safely contained in rat bait boxes), followed up by a barrage of traps inside the loft spaces and anywhere they run set with chocolate spread and peanuts (don't get any chocolate spread on the cables!!).

Red bromadiolone baits seem to work well all round (especially where there is resistance to poison), but sometimes are rejected by mice, so be prepared to use the blue difenacoum baits if there is not much take. Keep monitoring the take of bait and replace when necessary especially as a cold snap sets in.

Sounds a bit morose but, hopefully any mice that do come in die before doing any serious damage.

Ensuring internal holes are properly filled where services run between loft spaces etc. is always good practice, but often neglected.
Because a favourite trick for rats especially, is to open up holes where any services run if there is any air leakage between the areas. Cables, and plastic water/heating pipes, are easier to chew than building materials generally, and soon there are stripped cables or pin-prick leaks to contend with.

Hope this helps!

-------------------------
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The meaning of life is a blank sheet; write on it wisely. ~ M.Cutler.
 07 February 2013 10:19 PM
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stateit

Posts: 2410
Joined: 15 April 2005

Out in the sticks here I've noticed one reason rodents chew cables:

The cables are in the way.

If it's going through a hole in a joist, they'll want to get through that hole and gnaw the obstruction away.

They'll happily run across cables pinned to the top of joists without stopping and nibbling.

They'll happily run across cables layed over insulation without stopping and nibbling.

You can tell where they run over them by the 'mouse/rat grease' they leave over the cables.

As for rodents needing to gnaw to keep their teeth down: That's very true, but they'd much rather gnaw on a piece of wood or similar.

If you see a cable gnawed that's not through a joist it'll be because it interferes with their otherwise straightforward run. Think a loop of cable sticking up,

As you can tell, I've given it much thought: I come across it on a weekly basis on my beat.

They certainly don't chew cable for the sake of it - only if it's in their way or an intruding on 'their' run.

And you can bait and block holes as much as you want...

-------------------------
S George
http://www.sg-electrical.com
 07 February 2013 10:29 PM
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slittle

Posts: 3674
Joined: 22 November 2007

Yes, I'd agree. There tend to nibble to get past things but I have opened trunking where they've nest built and pretty much everything is stripped in there.

The other option to keep the little beast at bay is to leave a few live wires about that they can contact

Stu
 07 February 2013 10:33 PM
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stateit

Posts: 2410
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I've previously posted here a link to a piccy of a Wylex 3036 board with 2 fried mice in it...

At least it was good being able to show the customer the reason for their problems!

-------------------------
S George
http://www.sg-electrical.com
 07 February 2013 10:45 PM
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slittle

Posts: 3674
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I've got loads of pics like that.

I took the lid off a board and length of trunking on a farm last year. We counted about 30 in there including babies... Needless to say they were asked to leave.

Stu
 08 February 2013 12:00 AM
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Dave69

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The PVC makes great bedding for them.

Remember that the new regs will say that trunking must not have more than a 1mm gap in lids, etc.
 08 February 2013 07:31 AM
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dbullard

Posts: 1166
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I get a few every year,

Found them in flush plastered in light switches with flat channel, the good old round J'B curled around the L&N terminals when side by side, again in wylex boards, etc etc.

I haven't yet found any on newer jobs, i'e with newer colour cables and they have been in a few years now.

I also used get a fair bit of squirrel damage on one site, but when I re -wired it a couple of years ago moved everything inside the unit mounted in tube on the ceiling, no trouble after that apart from "rat" damage to the main equipotential bonds to the incoming oil line.

Regards

Daren


Daren

-------------------------
..... Dont pee in my pocket and tell me its raining ......


www.quest-electrical-sw.co.uk
 08 February 2013 08:21 AM
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broadgage

Posts: 1557
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Yes, well installed steel trunking or conduit is the way to deter rodent damage.

And as for WHY the pests chew cables, one theory is that these days a lot of food is stored in plastic containers, and that rats have learnt that by chewing through plastic that food might be found.

I dont remember rats chewing the old rubber twin or or twin with earth cables, and food is not often stored in rubber containers, so it sounds possible.
 08 February 2013 11:31 AM
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patt2

Posts: 526
Joined: 05 December 2005

I agree with stateit that it is mainly because the cables are in the way.

They seem to love pipe insulation though , and the neoprene type insulation they use in some cars.
I had a really badly mice infested bungalow loft where every accessible pipe had been completely stripped of insulation, but the alarm cables and T +E had not been touched.

I used two sonic devices and they cured the problem .
 08 February 2013 03:10 PM
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rocknroll

Posts: 9027
Joined: 03 October 2005

Unlike human beings the front teeth of rodents grow throughout their life, hence to trim them they chew soft materials like PE & PVC cables, wires, pipes, allied polymer products, to keep their teeth within size.

For sometime now the major manufacturers of pvc building products pipes, containment systems and cables have been adding non-harmful chemicals to the mix such as one of the denatonium compounds to eliminate the damage caused by rodents and hole boring insects.

Wood is also treated in the same way although that is an injection process, rodents gnaw at wood although the main concern here is anobium punctatum (woodworm).

There are also brush on non-harmful coatings if you have a problem

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------

Edited: 09 February 2013 at 12:05 AM by rocknroll
 08 February 2013 03:14 PM
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OMS

Posts: 20482
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There are also brush on non-harmful coatings if you have a problem


And of course, there's always that bloody cat - but then you have the dillema of opening the box -

OMS

-------------------------
Let the wind blow you, across a big floor.
 08 February 2013 03:22 PM
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rocknroll

Posts: 9027
Joined: 03 October 2005

Originally posted by: OMS

There are also brush on non-harmful coatings if you have a problem


And of course, there's always that bloody cat - but then you have the dillema of opening the box -

OMS




Thats right, send the cat in we have to maintain the balance.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------
 27 April 2015 09:59 AM
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Zoomup

Posts: 1425
Joined: 20 February 2014

To control mice invest in the "Z Zapper". This new innovation comprises a small box containing two holes suitable for mice ingress and egress. The floor of this amazing device has a cattle grid type conducting metallic surface. This H.V. grid is connected through a timer that has an on/off cycle of just 10 seconds. When the mouse enters the Z Zapper it sits pondering what to chew on, as little bits of food and PVC and wood are offered as bait. Then the timer connects the H.V. electrical supply and the grid painlessly atomises the beast. An automatic vacuum cleaner system then extracts the remains and the dust is shot out into space with an efficient "whoosh" sound, thus indicating to the householder that another efficient cremation of a pest has been successful. The Z Zapper has worldwide patents.

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Buy yours today whilst stocks last.
 27 April 2015 04:29 PM
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Jaymack

Posts: 5051
Joined: 07 April 2004

I have had a nest of mice in the sound proofing of a car bonnet, parked at the rear of the property. I don't know how long it had been there, but fitted one of those plug in pest deterrents on the outside of the garage, no problems after that. It had only chewed a hole in the padding and left the wiring alone.

I have had rats inside floor standing panels during installation, when they had chewed the insulation from the wiring, probably for nest material. Every works I was in had their works cats, hence the expression "More hours than the works cat", applied to those who worked a lot of overtime, but cats can also be a problem. One company where I was a young engineer, had steel tube rolling mills one of these had a cat which was in the open windings of a D.C. generator for a Ward Leonard set, when it was started up, this caused a fire which closed the mill down for 6 weeks while a rewind was underway. I've also had a moggie across the busbars inside a substation, when the contractor in their wisdom, had wedged open the cover to install a temporary power cable.

On the smaller scale, ants and spiders can also cause problems, hence the need to stick to IP ratings, and improve on them if possible.

Regards
 27 April 2015 08:25 PM
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mikejumper

Posts: 1935
Joined: 14 December 2006

Originally posted by: stateit
Out in the sticks here I've noticed one reason rodents chew cables:
The cables are in the way.
...

I've come across T&E chewed in a kitchen midway between joints.

Very old house with varnished floorboards, when the owner hung wet washing above the range she was getting a hissing noise from under the floor.

T&E was back to the copper for most of the length between the joists.
 27 April 2015 09:41 PM
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slittle

Posts: 3674
Joined: 22 November 2007

I'd always been told that rats wouldn't chew "blue" water pipe because of the texture.
From some pictures I was sent at the weekend, that's wrong !! which makes me think pvc containment could also be at risk if the rats are looking to cause trouble.

So much safer with mice


Stu
 27 April 2015 10:40 PM
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sparkingchip

Posts: 7365
Joined: 18 January 2003

Originally posted by: slittle

Probably the best method is plenty of bait, however this does provide an increased risk for us sparkies if we have to work near it.



I hear the ultrasonic units work quite well too.



Bear in mind if you are considering trunking or conduit that it needs to be done properly, a mouse will get through a hole about the size of a biro pen and as Andy has said, once in there they will spend their time chewing.





Stu


Mice have flat skulls and can shimmy through a 10mm slot, which is why mouse guards on bee hives have 10mm holes, not gaps or slots.

Andy
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