I've recently put on a new Cat and the bung for the downstream O2 sensor has the wiring about 1mm from the cat heat shield on the bottom of the car. It's close enough that it'll definitely burn threw the wires without protection so I wrapped the sensor and wires in several layers of aluminum foil as a temporary solution just for a few days. It works as far as heat transfer goes, but since I've done that I keep blowing one of my fuses and I'm almost positive its because the body of the O2 sensor is now grounded against the bottom of that heat shield it's pressed up against because of the aluminum foil. The best solution would be just to relocate the sensor. But other than that, is there some heat wrap/insulation I can put over the wires that'll stand up to the heat AND is not electrically conductive?

 

https://www.designengineering.com/cool-tube/

 

Do you know if that is electrically conductive?

 

I don't, but I'd imagine the inside isn't. Send them an email or give them a call - they're very good folks. They have other heat protective products as well which do not have the reflective outer shell.