Here's the reasoning. The 15/20-amp thing is especially confusing...
The original poster wanted to use a Surge Protector for his 20-amp trailer, and RV surge protectors are only available in 30 or 50 amp versions. That's why there needs to be a 20- to 30-amp plug conversion somewhere.
Surge Protectors are notoriously leaky and can cause nuisance tripping of a GFCI. (read the link above) which is why you generally don't want to plug them into a 20-amp GFCI outlet.
However, all 20-amp pedestal outlets in campgrounds are GFCI protected per Code.
And finally, NEMA 5-15p 15-amp plugs are actually rated at 20-amps. The only difference between a 15-amp and 20-amp plug is the orientation of one of the blades. As long as there's 12-gauge conductors on the 5-15p plug, then it's rated for 20-amps.
So every adapter you find will have a 5-15p plug, which plugs into a 5-20r receptacle on the pedestal and is rated for 20-amps.
Here's the reasoning. The 15/20-amp thing is especially confusing...
The original poster wanted to use a Surge Protector for his 20-amp trailer, and RV surge protectors are only available in 30 or 50 amp versions. That's why there needs to be a 20- to 30-amp plug conversion somewhere.
Surge Protectors are notoriously leaky and can cause nuisance tripping of a GFCI. (read the link above) which is why you generally don't want to plug them into a 20-amp GFCI outlet.
However, all 20-amp pedestal outlets in campgrounds are GFCI protected per Code.
And finally, NEMA 5-15p 15-amp plugs are actually rated at 20-amps. The only difference between a 15-amp and 20-amp plug is the orientation of one of the blades. As long as there's 12-gauge conductors on the 5-15p plug, then it's rated for 20-amps.
So every adapter you find will have a 5-15p plug, which plugs into a 5-20r receptacle on the pedestal and is rated for 20-amps.
https://www.rvtravel.com/rv-electricity-jam-15-amp-bonding-plug-20-am-generator-outlet-rvdt-1976/