Best to get a "canning" element - sturdier, sits up a bit higher than the normal burner above the stovetop. Designed to hold oversized pots...
I always line the reflector pan with fresh, bright aluminum foil if the old stuff is crusty or dark, and often cover the stovetop under the pot with foil as well - more for drips, but will also help with overheating somewhat.
Something like 15 years of doing it this way, no problems.
As for inside the pot wort/extract scorching (even though that is not your question), I take the pot right off the stove (I have a metal typing table I use to move the pot across the kitchen so I don't have to walk with boiling-hot wort when I'm headed for the sink at the end of the boil) and stir in the extract, then put it back on the burner after it's well-mixed. Could also just move it sideways to a cold burner for that step.