Example of a burnt out roof-top DC isolator
Poor earthing (between earth shim and fixing). The indicator should be at the extreme left!
This is the reading one would normally expect.
safety
These are examples of some of the issues that can (and do) go wrong when components are not installed to manufacturer’s specifications.
Often it makes little difference whether the switch is a high-quality one or not; if the installer/licensed electrician does not install it to the correct standards then they can fail, and lead to arcing and fire.
Images provided below approved by relevant customers.
An ABB DC isolator from a commercial install
Moisture penetration led to the failure here.
Benedikt & Jaeger isolator
Evidence of the water line.
Benedikt & Jaeger isolator
Penetration incorrectly sealed.
Incorrect adaptors and glands used
Silicone is not an approved means for achieving IP ratings.