Why does the bucket in a bucket truck need to be solid to maintain grounding?

Question

I’m watching this arborist on YouTube and they have a truck with a bucket on an arm so they can reach heights without climbing. On/after a rainy day the bucket will accumulate water and they mentioned they can’t drill a hole to drain because it will compromise the grounding.

My understanding of grounding/electricity doesn’t explain this. Can someone help me understand why this would make a difference?

Edit: I get it, I/he should have said “electrical isolation” instead of “grounding”. Either way, a hole allowing a stream of dirty water seems to be the answer here. Thanks 🙂

In: Physics

Answer 1

“The purpose of the solid bucket is to maintain electrical isolation, not grounding. People just confuse the two.”

This really sums it up.