Are rodents considered a form of physical damage ?

ritelec

Senior Member
Location
Jersey
I replaced some nm cable damaged from squirrels with thei lighter mc cable.
Think they would eat through it or move along?

In the code when they say exposed to physical damage, would something like squirrels or mice entering be considered that ? I mean how would you know if they were going to decide to sojourn there ?
 

petersonra

Senior Member
I replaced some nm cable damaged from squirrels with thei lighter mc cable.
Think they would eat through it or move along?

In the code when they say exposed to physical damage, would something like squirrels or mice entering be considered that ? I mean how would you know if they were going to decide to sojourn there ?
I would not consider it that way.
 
As ill defined as exposure to physical damage is in the NEC I don't think damage from rodents is in the scope of it.

Two feet of dirt is blessed by the NEC as adequate protection of direct bury conductors yet annually we dig up and repair irrigation pivot wires that have been chewed by varmits.
 
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ptonsparky

Senior Member
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
Electrical Contractor
As ill defined as exposure to physical damage is in the NEC I don't think damage from rodents is in the scope of it.

Two feet of dirt is blessed by the NEC as adequate protection of direct bury conductors yet annually we dig up and repair irrigation pivot wires that have been chewed by varmits.
And some of those deep tillage implements will get them if the sand has moved around a bit.
 

ptonsparky

Senior Member
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
Electrical Contractor
I replaced some nm cable damaged from squirrels with thei lighter mc cable.
Think they would eat through it or move along?

In the code when they say exposed to physical damage, would something like squirrels or mice entering be considered that ? I mean how would you know if they were going to decide to sojourn there ?
I would not count on AL MC being safe from rats or squirrels, but I am not going to work that into an NEC interpretation of exposed to physical damage.
 

gadfly56

Senior Member
Location
New Jersey
When I was a wire jockey we occasionally worked in horse barns. For whatever reason, the critters than normally call such a space home really loved the FPLP we'd install. My boss had us run everything in EMT for that sort of location.
 

growler

Senior Member
Location
Atlanta,GA
I replaced some nm cable damaged from squirrels with thei lighter mc cable.
Think they would eat through it or move along?

Could a squirrel eat through MC cable? They probably can but I haven't seen any that was damaged by squirrels.

From talking to an exterminator ( professional squirrel terminator ) I learned that squirrels don't really eat the insulation of wire they chew on it when young (teething ring type thing). The thing is this, would young squirrels use the Al covered MC to chew on like the soft outer covering of MN ? Maybe some of those genetically modified squirrels.

The real way to protect a house from squirrels is to make sure it's sealed properly to make sure they can't get into the attic or crawl space to raise their young.
 

kwired

Electron manager
Location
NE Nebraska
When I was a wire jockey we occasionally worked in horse barns. For whatever reason, the critters than normally call such a space home really loved the FPLP we'd install. My boss had us run everything in EMT for that sort of location.
EMT isn't even safe from 500 - 2500 pound animals. I run RMC if it will be expected to be in direct contact with such beasts, and they still damage that at times.

Keeping it out of reach period is the best, but occasionally that just doesn't work out. Like when the ground is frozen and the underground line to the water tank heater has failed - you run RMC in as best protected location as you can to get by with.
 

gadfly56

Senior Member
Location
New Jersey
EMT isn't even safe from 500 - 2500 pound animals. I run RMC if it will be expected to be in direct contact with such beasts, and they still damage that at times.

Keeping it out of reach period is the best, but occasionally that just doesn't work out. Like when the ground is frozen and the underground line to the water tank heater has failed - you run RMC in as best protected location as you can to get by with.
The critters I was referring to were the family rodentia, not equidae. Typically the damage was found in the storage spaces above the stalls, tack rooms, etc.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
It is my opinion that damage by animals, either of the 4 legged type or the 2 legged type, is physical damage that the code requires us to protect our wiring methods from.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Pretty broad statement.
Just like the requirement that we shall not install some wiring methods where the wiring method it subject to physical damage.

If the "physical damage" envisioned by the code is not damage caused directly or indirectly by "animals" than what is it caused by?
 

GoldDigger

Moderator
Staff member
Bay Area Rapid Transit (BART) direct buried hundreds of miles of signal and data cable only to find that the sheath was irresistible to gophers. Big money lost.
No idea whether BART's insurance or designers' E and O covered any of the cost of rewiring.
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
I would think that you would be remiss in not finding a better way to do it if you knew there was a chance such as in a barn or shed. I got lucky and had rats in our attic, but they never bothered the wiring, but I've found dead mice, on fire blocks, half way down the wall, in other houses, where they chewed through the cable. As I was told by an old watch seller one time, "cheap is expensive."
 

ptonsparky

Senior Member
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
Electrical Contractor
I would think that you would be remiss in not finding a better way to do it if you knew there was a chance such as in a barn or shed. I got lucky and had rats in our attic, but they never bothered the wiring, but I've found dead mice, on fire blocks, half way down the wall, in other houses, where they chewed through the cable. As I was told by an old watch seller one time, "cheap is expensive."
We have been in places where space is the only insulation left. Rats chew thru the wire as well, if the CB trips.
 

romex jockey

Senior Member
Location
Vermont
Imho, the code for physical damage has to remain interpretational , simply due to it's inability to detail every element in the physical universe.

That said , i understand there was some past concern about soy inclusive in romex manufacturing ....?

Not sure about the details....


~CS~
 

Carultch

Senior Member
Location
Massachusetts
I replaced some nm cable damaged from squirrels with thei lighter mc cable.
Think they would eat through it or move along?

In the code when they say exposed to physical damage, would something like squirrels or mice entering be considered that ? I mean how would you know if they were going to decide to sojourn there ?


The wiring in this house was "subject to physical damage" too. But we don't expect that contractor to run rigid RMC encased in concrete for this hopefully unlikely event.
 

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