http://www.cableorganizer.com/abrasi...tant-sleeving/

sleevings will protect cables from cuts, scratches and other abrasions.
Several types are available, including stainless steel, Nylon and Kevlar
examples, but all feature woven designs that allow for flexibility while
keeping cables, wires, and hoses free from damage, and most are expandable
to allow for maximum versatility. We offer both side entry wrap-around and
feed-through installation options. Metal Braided Sleeving - Our flexible
tin-coated copper sleeving shields cables against electromagnetic and radio
frequency interference while protecting them from abrasion and gnawing
animals.

http://www.instructables.com/id/Rabb...xtension-cord/

Protect extension cords by keeping them off of the floor, running them
through PVC pipe and sealing the ends with duct tape or wrapping them in
duct tape. Rats don't like the sticky glue on the tape and will not chew
through it.

http://www.ehow.com/how_8796229_ratproof-wiring.html

http://www.ianrpubs.unl.edu/pages/pu...blicationId=23

Physical Abilities of Rats and Mice
To prevent rodent entry, their capabilities must be understood. For example,
rats and mice can:

a.. run along or climb electrical wires, ropes, cables, vines, shrubs, and
trees to gain entry to a building;
b.. climb almost any rough vertical surface such as wood, brick, concrete,
and weathered sheet metal;
c.. crawl horizontally along pipes, augers, conveyors, and conduit; and
d.. gnaw through a wide variety of materials, including aluminum sheeting,
wood, rubber, vinyl, plastic, and concrete block.
In addition, rats can:

a.. climb the outside of vertical pipes and conduit up to 3 inches in
diameter, climb the outside of larger pipes attached to buildings by bracing
themselves against a wall, and climb the inside of 1½- to 4-inch vertical
pipes;
b.. jump up 36 inches vertically and 48 inches horizontally;
c.. drop 50 feet without serious injury;
d.. burrow straight down into the ground at least 36 inches;
e.. reach up to 13 inches along vertical walls; and
f.. swim half a mile in open water, dive through water traps in plumbing,
and travel in sewer lines against a substantial current.
The paired front teeth (incisors) of rats and mice curve slightly inward,
making it difficult for them to gnaw on round surfaces larger than 7/8-inch,
flat, or harder than iron (such as steel). Thus, when given a rough surface
or an edge, they can quickly gnaw into most materials. Take special care to
locate and secure all structural crevices. Rats only need slightly more than
a ½-inch gap to enter; mice only need slightly more than a ¼-inch gap
(Figure 2). Don't ignore smaller crevices as rodent gnawing can quickly
enlarge them.