The 200 will have a 6-50 plug on it...if it's a ST model at least. The 6-50 should be the ONLY choice for you as it is the approved/designated welder plug in the US and is the best way to ensure compatability with other welding/cutting devices in the future. The red wire won't be present on the 200. It isn't 3 phase. You need to just go with a 50 amp. That'll give you enough power in most cases if it is a dedicated circuit. Home Depot does carry the receptacles around where I live.