Do not assume you can put two rated cables together to extend your length.
Length and wire size are tied together to give you minimal line loss.
The L5-30 is the most commonly supplied outlet for portable generators.Two smaller wire sizes although rated at a specific amperage will not be big enough and you can see significant voltage loss. The important aspect is to use rated connectors and then match a length of wire that has appropriate wire size to minimize voltage losses.When determining the wire sizes we recommend Paige Wire Calc or Wikipedia for wire gauges that go into this in detail needed to size your wire.Here are some of the top sellers and quality cords: L14-20 Power Cords Reliance Controls PC2010 10-Foot 20 Amp L14-20 Generator Power Cord For Up To 5,000 Watt Generators Conntek 20591 Generator Extension Cord 25-Foot 10/4 20 Amp 125/250 Volt 4 Prong Extension Cord Conntek 1.5-Feet, 20-Amp L14-20P 125/250-Volt to (4) 15/20-Amp Female Connector, 4 Prong Generator Locking Extension Cord L14-20P to L14-20R Extension Power Cord, 50 Foot – 20A, 125/250V, 12/4 AWG L14-30 Power Cords L14-30 Generator Power Cord – 50 Foot, 10/4 Wire, 30 Amps, 125/250V Conntek 20601-020 20-Feet, 30-Amp 125/250-Volt L14-30P/R , 4 Prong Transfer Switch Cord/Generator Extension Cord Reliance Controls PC3010 10-Feet 30-Amp L14-30 Generator Power Cord for up to 7500-Watt Generators Coleman Cable 01934 3-Feet Generator Power Cord Adapter, 10/4 Splitter Y Adapter, L14-30P to (2) 10/3 Lighted 5-20R The 14-50R appears with the larger units, it is not a locking outlet primarily due to the expense at this rating in making the receptacle.If you have a unit equipped with this size outlet you will need to ensure you clip it and protect it against pull out. Camco 55195 50 AMP 30′ Extension Cord with Power Grip Handle Generac 6389 25-Foot 50-Amp Generator Cord with NEMA 1450 Male End and CS6364 Female Locking End (Back to Top) Both the L6 and L10 is for 240V in a three prong configuration. The one thing that does occur is the TT and NEMA 10 are sometimes confused. The NEMA 10-30 is typically used for electric dryers.