The cleanest way to make up a pig tail for the 24 volt outlets is to buy a molded Italian Type L wire and cut off one end. The last one I made up used this from ebay:
DELL 6FT 3-PRONG TYPE L 10A 220V ITALY CHILE AC POWER ADAPTER CORD CABLE 23322
that costs only $5.39 including shipping. It cheaper than a Btinico Italian Type L plug and because the plug is molded to the wire, there is no issue with moisture. The cigarette lighter plugs are easy to find everywhere, I have purchased 12 volt extensions and cut off the male plug ends so both ends of the pig tail are molded and weatherproof.
"Sabbatical III" SM419, Wickford, Rhode Island