Hello, Carnage !
I hope this finds you and yours well !!
I only use 12awg extension cords in the Shop for all equipment, including the Metrovac Vacuum, the Metrovac Master Blaster, the Steamer, and the Extractor.. I want the bigger gauge wire and the thicker insulation..
My small air compressor, which I only use for airing up the tires, etc., I use the same 12awg extension, because I have several of them and they are easier to use.. Because they are heavier, if they are wound up in large coils, they will uncoil easier and lay flat better.. For a bigger air compressor, it would only be best to use a heavier extension cord if you had to use one..
I would
never use a 6-outlet strip
anything... This puts all the heat on that strip and as you found out, it is the weak link and will be dangerous if it catches on fire...
No Air Conditioner should ever be run on 14awg or smaller wire... Notice how thick the electrical plug wire is from that machine?? Yeah, it is like that for a reason.. It Needs more juice to run and not overheat itself and implode on you.. Especially since this machine will run for hours on end cooling the room, right ?
The only adapter I have ever considered using to power up more than 1 machine on the same extension, would be this --
https://www.amazon.com/Yellow-Jacke...&refinements=p_n_feature_keywords_browse-bin:
This is a 12awg adapter, but you still have to watch it, and not just trust blindly that it will never fail.. Especially if it is made in China..
It will always be best to have a few dedicated electrical circuits if possible, so that you can plug different items into each of these, and they run through 12awg wires directly to separate circuit breakers on the Power Panel..
If this is not possible, you have to be mindful of how many things are running on that 1 circuit breaker.. It will usually break the circuit if it gets overloaded, then gets too hot.. You don`t want this to be the normal ever..
Yeah, I have seen a lot of Shops with those extension cords all over the place !! Drives me crazy!!

Eventually they all get damaged, the wires get creased, start to break, and then blows the breaker in the panel..
Then, they probably just throw the extension cord away and get a new one from the cabinet..
I will never do this ! But that`s just me..
Dan F