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Rodents chewing through cables

Rodents chewing through cables

Rodents chewing through cables

(OP)
I am having problems with mice/rats chewing through wires.  Our unit sits flush with ground level, and has several sealed, removable compartments.  The wiring harness running between these compartments is being chewed through.  Rigid conduit is not an option since we need to be able to disconnect the various components.

As for other pertinent information; the cables range from CAT5e cable to #6 AWG four conductor cables.  The run lengths are 2-6ft, and space if very limited, so flexibility of the wire is important.

I know this is not a unique problem, but haven't been able to find a feasible solution that fits our applications.  Right now I'm looking for some sort of armored cable.  The problem will be trying to transition from this to our water tight connectors.  

Short of completely redesigning our entire system so that the mice can't get, is there anything that you have used or could recommend?  

Thanks in advance.
 

Engineering is the art of modelling materials we do not wholly understand, into shapes we cannot precisely analyse so as to withstand forces we cannot properly assess, in such a way that the public has no reason to suspect the extent of our ignorance.
-A R Dykes
 

RE: Rodents chewing through cables

From looking up cable sheath rodent protection I get:

http://www.ricelake.com/docs/browse.php?categoryID=1514

http://www.procentec.com/products/productdisplay.php?index=37

http://www.datapacksystem.com/data/draka/e11dq.pdf

Surely there is a product a bit like the flexible tubing/houses often used on domestic sinks etc?  Maybe you could even use that if you need to retroit.

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RE: Rodents chewing through cables

A few underfeed cats could do the trick for you.

RE: Rodents chewing through cables

Lots of rat poison

RE: Rodents chewing through cables

Tabasco.

Mike McCann
MMC Engineering

RE: Rodents chewing through cables

Cats chew wires too.

- Steve

RE: Rodents chewing through cables

Tabasco mightn't work if they are South American rats.

RE: Rodents chewing through cables

Our natural gas engines for oil rigs are wired with aluminum braid armored cable and epoxy sealed gastight connectors.  

Relatively flexible.

Probably rat- resistant.  

Bring your wallet.


 

Mike Halloran
Pembroke Pines, FL, USA

RE: Rodents chewing through cables

Well, then it's back to stainless braid, I guess.

Buy some braided hose, pull out the hose, use the braid.

 

Mike Halloran
Pembroke Pines, FL, USA

RE: Rodents chewing through cables

(OP)
Right now we are debating between stainless braid and Kevlar braid.  Has anyone used either of these specifically for rodent gnawing?  If so, what were your results?  The hardest part will be testing.  I'm not sure that I could swing the straight forward test of getting a few test subjects from the pet store and putting their food inside the braid, and waiting to see if they get in or starve.(the boss may not like that approach).

My first suggestion was a snake (Middle Eastern desert environment), as the cat may not do well in the desert.

The Tabasco sauce may work, but then I would have to figure out how often they need to reapply, and what if the rats developed a taste for it.  I did read somewhere that dielectric grease seemed to turn them off, but then it comes back to constantly having to put more on, and as soon as you forget, the system is down.
 

Engineering is the art of modelling materials we do not wholly understand, into shapes we cannot precisely analyse so as to withstand forces we cannot properly assess, in such a way that the public has no reason to suspect the extent of our ignorance.
-A R Dykes
 

RE: Rodents chewing through cables

In my opinion, SS will substantially outperform aramid fibre (Kevlar is DuPont's brand name for aramid, but there are other suppliers) in this application as aramid is prone to fibrilation on compression.

I feel nothing short of SS braid will work. I would retain the liner as an extra layer to better spread the point pressures over the cable or the occasional tooth penetration between the braid fibres.

Waterproof by encapsulation inside and out with epoxy or polyurethane "potting resins" at the joints.

Regards
Pat
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RE: Rodents chewing through cables

Stainless, for the same reason many 'bullet proof vests' aren't knife proof I suspect the same will be true of aramid & rats teeth.  For this application hardness, not just strength, is important.

As to the testing.  Try and find out the bite strength of your suspected rodents, Bite force measurement in awake rats for instance.  Then go from there.  

You could build a simulated rats jaw with hydraulic ram or similar (maybe pneumatics) and cycle it a few times to simulate gnawing (I've seen this on discovery channel etc when they compar different animals bit force etc).  Or you could just do a single test with a rat tooth sized 'chisel' or similar and see how much force it takes to penetrate, if this is a lot higher than a rats force you may be onto something.  You also may want to take the relative hardness of the rats teeth into consideration.  You may be able to calculate or simulate some of this but where's the fun in that.

(Mike - braided hose that's what I meant in my first post, couldn't remember the name)

Another idea, you oviously have power so how about one of those ultrasonic pest deterant devices?

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RE: Rodents chewing through cables

We had a mouse problem after remodelling.  The rodent control expert we hired plugged holes/gaps in the floors with copper wool.  Surprisingly effective.  Dunno if it would work for rats, esp. if they are already chewing through copper wires...

RE: Rodents chewing through cables

I've heard steel/wire used for the samae.

Another use of steel wool is in rodent control. Small holes are plugged with steel wool which if gnawed on by rodents causes sharp pain in the mouth, and if ingested, severe internal damage, leading to death.  http://en.wikipedia.org/wiki/Steel_wool

I did think yesterday of suggesting he wrap the cables in wire wool but that didn't sound right somehow.  I got the impression plugging the equipment may not be practical either.

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RE: Rodents chewing through cables

Might be squirrels...  My next door neighbor had much of the wiring eaten out his old clunker pickup truck.  They have eaten through my lead bathroom roof vents, outdoor aluminum light fixtures and even the inground lawn sprinklers.

Not sure why the baby squirrels don't have six legs or two heads --- but they keep coming as much as I shoot or poison them..

RE: Rodents chewing through cables

Mike, you just need a good squirrel dog.  They don't even come into our neighbors yards any more.

Patricia Lougheed

******

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RE: Rodents chewing through cables

Yagonyonok,

   Kevlar has a low elastic modulus, which makes it resistant to impact loads.  This is probably not a problem with rats.  I agree with the comments about stainless steel, above.

   Some cats chew on wires because they perceive them as playtoys.  If the cables are heavy enough and/or properly tied down, they will not be attractive to the cat.  Cats are more voracious than snakes, they are cuddlier, and they are much safer to handle than a lot of desert snakes.  They can be a distraction sometimes.  

   Can you modify your modules so that they slide in and engage connectors at the rear like with a VME or cPCI rack or an ARINC box?  This eliminates the need for flexible cables.  

               JHG

RE: Rodents chewing through cables

We've had rats in our garage.  They've chewed through PET juice bottles and containers as if they were paper.

I think that anything that's softer than tooth enamel will be at risk...

TTFN

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RE: Rodents chewing through cables

(OP)
Kenat,
I just ordered some of that to try.  Thanks for all the advice.

Engineering is the art of modelling materials we do not wholly understand, into shapes we cannot precisely analyse so as to withstand forces we cannot properly assess, in such a way that the public has no reason to suspect the extent of our ignorance.
-A R Dykes
 

RE: Rodents chewing through cables

Good looking stuff!

That will slow them down severely -- but may not stop them.

Depending on the rats' determination, you may need to put some nasty sticky stuff (same goo they put on glue traps for mice) on your cable, then a sacrificial wrap on top of that.  Direct-bury coax cable can be bought with this feature already in there.  The animals can start to chew, but they're repulsed by the taste and texture of the sticky stuff.

My rat experience involved instrumenting rat cages for temperature monitoring for a VA hospital laboratory years ago.  Stainless 316 probes, 16 ga wall thickness, lasted about three weeks between replacements. The rats would gnaw all the way through, my 4" probes would be in two completely separated pieces.

I'm not sure where to get the goop -- perhaps a local pest control company?  Don't know where to buy the coax I mentioned either, but it's what the local cable company in Memphis originally put in.  Even the raccoons won't bite all the way into it when it's sitting out above grade for their chewing pleasure...

Good luck with it, and please let us know what works!

Good on ya,

Goober Dave

RE: Rodents chewing through cables

Have you looked at the flexible conduit systems from the likes of Kopex, Adaptaflex and so on? http://www.kopex.co.uk/productpage.asp?a=2 They do a few stainless options.

UK rats don't normally carry hacksaws. Gyppo's - a close relative of rats, but able to walk upright - usually do. smile
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: Rodents chewing through cables

Scotty,
I do believe that is an ethnic slur, be careful, you will offend the rats.

Some years ago, we would wrap data cables with one pound sheet lead strips, the rats would chew on this for a while, then lose interest.
B.E.

RE: Rodents chewing through cables

Now that would be risky today: either the rodents would sue you for heavy metal poisoning, or someone would pinch the lead for scrap value!

No offence intended to any rodents reading this. smile
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

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