[masraum]

Originally Posted by mjohnson

"rubber" as you get it from a petro-plant or from a tree is an insulator. It's also kind of crap on its own for tires, so for that and other reasons we load it with carbon black (basically soot). Hence your black tires. It's better for its use and a little more electrically conductive. Now, load it with more conductive things and you can dissipate the static charge. No charge buildup = no electrical sparks.

In some workplaces that really, really care about static electricity - like with flammable liquids/gasses and propellants/explosives - you wear dissipative footwear and even make sure that your "rubber" tired furniture conducts enough electricity to the floor so as to prevent a charge buildup.

I've been places where you had to stand on a mat and get measured - if you weren't dissipative enough (i.e. "grounded") you couldn't even insert your access card to open the door.

And, now thinking about this, I finally understand why lots of vehicles like ambulances might have loose chains dangling and jingling. Thank you! Now I realize that I kind of knew but didn't really ponder it...

In addition to dangerous situations (around inflammable explosive materials) working with sensitive electronics often also has a requirement for folks to be grounded (wrist straps, mats to stand on, etc...).