What kind of extension cord should I get for my RV?

Get a 30-amp or 50-amp cord designed specifically for RVs, not a household extension cord. Most travel trailers use a 30-amp cord with a TT-30P plug, while larger motorhomes use a 50-amp cord with a NEMA 14-50P plug. Never use a standard 15- or 20-amp extension cord—the wire gauge is too thin, risking voltage drop, melted plugs, or fire.