Quote Originally Posted by Saint-Just View Post
1) because there usually is lighting, and a short circuit created by a gnawed wire could lead to a fire that would remain undetected until it sipped below

2) in my case because that is where the boiler is.

You are quoting what you, yourself have fitted, not what regulation requires.

Gnawed wiring will generally (almost all) cause the RCD (if fitted of course) to trip. I appreciate that not all houses have RCDs covering all circuits.