Floating on air? Sulphur Hexafloride

I liked the third comment about advanced technology looking like magic.

Pressurized SF6 is used as an insulating medium in high voltage switchgear. You can walk up to 500 kv and put your hand within ~ 3 feet of the live conductor. John T.

It's not magic and it's not advanced technology. It's voodoo, pure and simple.

It's also used to replace vitreous fluid for eye operations like macular hole repairs. It eventually is absorbed and replaced with fluid. The downside is it can hasten cataract formation.

It's a little weird as it is replaced and you regain partial vision. The retinal image is upside down so what you see isn't what you would expect from the fluid filling in from the bottom.

SF6 has a relatively low resistance in an arc, which means relatively low heat when a high voltage switch opens. And it rather abruptly transitions from plasma to an insulator when the switch opens. That is a couple more reasons it is good in a high voltage utility switch. A switch may have a huge insulator and the switch enclosure is tiny, although part of having a large insulator is to have a long surface leakage path.

I thought it was fairly ugly as a chemical, but that may be temporary breakdown products in the arc when opening.

Yep - but not temporary - a residue is left behind after arcing which requires some care during the 10 or 20 year maintenance cycles. John T.