This AC WORKS brand adapter SS2630-018 is heavy-duty and very durable..5FT 50A 125/250V SS2-50P/CS6365 Plug to 30A 250V 6-30R Commercial HVAC Adapter Cord This adapter is frequently used to power HVAC from a twist-lock 50A outlet. The adapter is a NEMA SS2-50P to NEMA 6-30R.