When you see cute rodents scurrying along the ground, they appear
If there's a small opening, rodents will get in. If an enclosure is improperly sealed, the critters will gnaw through wood, plastic and cables in search of food. Any soft material such as wire insulation will not endure the razor sharp bite of mice, rats & squirrels.
Don't get me wrong, I like rodents and will always remember my pet hamster from when I was a child. But electrical equipment must be protected from their never-ending forage. And, as electrical consultants, we sometimes recommend rodent-proof enclosures that can protect equipment and increase safety for both humans & mice.
Vermin are not attracted to the protective cable shield nor to the electric charge of the wire but will chew through any non-metallic barrier to get to their destination. As their furry & conductive bodies come into contact with energized components, they case phase-to-phase or phase to ground short circuits.
Breakers usually handle the over-current situation but sometimes the amount of energy released can damage equipment, especially at the higher voltages.
Poor Fukushima Daiichi. After getting swamped by a tsunami in March 2011, they were hit with a 30 hour power outage in March 2013 that was suspected to be caused by a rat in the switchgear.
"We have deeply worried the public, but the system has been Rat in the Fukushima Daiichi nuclear facility restored," Tepco spokesman Masayuki Ono was quoted as saying by AFP news agency.
The power outage at the nuclear facility shut down the cooling systems for four spent fuel ponds, although the cooling systems for the reactors were not affected. The spent fuel ponds contained highly radioactive nuclear fuel rods and the incident became another international PR disaster for the facility. All because of a rodent.
During our electrical distribution assessments, we've encounter rodent ingress in electrical enclosures, panel boxes and even distribution boxes (we found their feces).
These spaces offer shelter & possibly warmth. Since we usually deal with circuits under 600V, the circuit breakers have done their job by tripping and thus, protecting the equipment.
But as circuit breakers age in the Canadian weather, they may seize and fail to break the over-current condition. This dangerous condition poses a shock & fire hazard that can escalate into lost revenue, large repair bills & an immeasurable PR disaster.
How to Protect Electrical Equipment from Rodents
To protect you & your facility from rodent damage:
- Learn what rodents are in your area. Skunks can dig under security fences. Raccoons can climb chain-link fences. What are the threats to your electrical system?
- Climate change is affecting migration routes. We"re seeing racoons in Calgary and more marmots in Kelowna! Are unfamiliar creatures moving in to your area that you were not previously guarding against?
- Assess the worst case scenario. For instance, gophers pose a danger to buried cables not in conduit but they also attract hawks which may be a bird-strike hazard near airports.
- Close up all small holes where cables enter & leave rooms and exterior walls.
- If liability is large, then secure equipment in a rodent-proof enclosure. This may require additional heating & cooling systems for the equipment.
- Temporary electrical equipment have new scents to be discovered by rodents. As what may have happened in Japan, temporary equipment needs to be rodent-proof as well.
Contact ICS Engineering to increase the reliability of your electrical distribution system.