Direct answer: If rats chewed an exterior light wire, shut the circuit off before touching anything. Exposed or nicked conductors outdoors can arc, trip breakers, shock you, or keep taking on moisture until the damage spreads.
Most likely: Most often, the visible damage is at the fixture whip, socket leads, or wire insulation right where the cable enters the light. If the wall cavity wire was chewed too, that moves out of simple fixture repair and into electrician territory fast.
Start by figuring out whether the damage is limited to the light fixture itself or reaches into the house wiring behind it. That split matters more than anything else. Reality check: if you can see bare copper outdoors, this is not a 'watch it for now' problem.
Don’t start with: Do not tape over chewed wire and turn the light back on. That is the common wrong move, and it leaves damaged copper and outdoor moisture in play.
The exterior light will not turn on, but the breaker is not tripped and other lights on the circuit may still work.
Start here: Start with a visual check at the fixture after shutting power off. Dead light with a stable breaker often means the chewing damaged fixture leads, the socket, or the lamp holder area.
The breaker trips right away or shortly after the switch is turned on.
Start here: Treat that as likely conductor damage or moisture at exposed wire. Do not keep resetting the breaker. Shut it off and inspect only with power isolated.
There are tooth marks, missing insulation, or loose wire strands near the light or where the cable enters the fixture.
Start here: Assume the damaged section is unsafe until proven otherwise. Your next job is to tell whether the damage stops at the fixture or continues into the branch wiring.
The light comes on intermittently, especially in damp weather or when the fixture is bumped.
Start here: Intermittent operation after chewing usually points to nicked conductors, loose wire connections, or moisture getting into damaged insulation. Shut power off before opening anything.
Rats often work on the softer insulated leads inside the fixture canopy or right at the entry point where the wire is easiest to reach.
Quick check: With the breaker off, remove the fixture enough to inspect the short fixture wires and look for tooth marks, missing insulation, or broken strands.
If the chewing happened inside the head of the fixture, the bulb may stay dead even though the house wiring in the box is still intact.
Quick check: Look for brittle, blackened, or chewed wires at the socket area and signs of heat or arcing around the bulb base.
If the rats reached the house cable itself, you may see damage on the insulated conductors or the outer cable jacket where it enters the box.
Quick check: After power is off, inspect the cable entering the box. If the house cable sheath or individual branch wires are chewed, stop DIY.
Outdoor fixtures fail fast once damaged insulation lets water into splices or onto exposed copper, especially after rain or heavy dew.
Quick check: Look for green corrosion, rust streaks, water marks, or a breaker that trips more often in wet weather.
Chewed exterior wiring is a live-shock and fire problem until you prove otherwise. You want the circuit dead before you touch the fixture, bulb, box, or mounting hardware.
Next move: The fixture stays dead and the breaker remains off, so you can move to a careful visual inspection. If you cannot identify the right breaker, the breaker will not stay set, or you are not sure the fixture is de-energized, stop here and call an electrician.
What to conclude: You need a known-safe starting point before deciding whether this is fixture damage or house-wiring damage.
This is the main split. Fixture-only damage may be a manageable repair. Damage to branch wiring in the box or wall is not a good DIY gamble outdoors.
Next move: If the house cable looks intact and the damage is limited to fixture leads, socket wiring, or the fixture body, you can keep diagnosing the fixture. If the house cable sheath is chewed, the branch conductors are nicked, or the damage disappears back into the wall, stop and call an electrician.
What to conclude: Visible damage limited to the light fixture points toward fixture repair or replacement. Damage on the branch cable means the problem is beyond the fixture boundary.
Once rodents chew insulation, loose strands and moisture can burn up the socket area. A dead or flickering light may be more than just cosmetic wire damage.
Next move: If the damage is confined to the socket area or fixture leads and the mounting box wiring is sound, the fixture can usually be repaired with the right fixture-specific part or by replacing the fixture. If the damage is widespread inside the fixture, the metal body is scorched, or moisture has been sitting inside for a while, replacing the entire exterior light fixture is usually the cleaner fix.
Guess-buying is how people end up with the wrong part and the same unsafe wiring. Match the repair to what you actually found.
Next move: You have a clear next move: replace the damaged fixture part, replace the fixture, or escalate for branch wiring repair. If you still cannot tell where the damage stops, keep the breaker off and bring in an electrician rather than energizing a maybe-safe repair.
The job is not done when the wire looks better. You need the fixture reassembled, protected from weather, and stable under normal use.
A good result: A steady light, no breaker trip, and no heat or buzzing point to a successful fixture-side repair.
If not: If the breaker trips, the light flickers, or the fixture gets warm in the wiring area, shut it back off and call an electrician to inspect the circuit and box wiring.
What to conclude: A stable test run in dry and damp conditions helps confirm you fixed the actual damage and not just the obvious bite marks.
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No. Tape is not a proper repair for chewed conductors outdoors. If copper is nicked, strands are broken, or moisture has gotten in, the safe fix is replacing the damaged fixture part, replacing the fixture, or having the branch wiring repaired by an electrician.
After the breaker is off, remove the fixture enough to inspect both sides. If the chewing is only on the short fixture leads, socket wiring, or inside the fixture body, that is fixture damage. If the cable entering the box from the wall is chewed or the damage continues into the wall cavity, stop DIY and call an electrician.
Chewed insulation can let hot and neutral touch, let a hot wire contact metal parts, or let moisture bridge damaged conductors. Any of those can create a short or ground fault and trip the breaker.
Replace just the exterior light socket when the damage is limited to the lamp holder area and the rest of the fixture is clean and sound. Replace the whole exterior light fixture when several internal wires are chewed, the socket area is burned, or corrosion and moisture have gotten into multiple parts of the fixture.
Yes, if there was visible chewing on the house wiring, any sign of heat or arcing, or the light flickers or trips the breaker afterward. A light that comes back temporarily after moving damaged wires is not a trustworthy repair.