The straight  240-volt  Welder Service. 

The 30 and 50-amp 240-volt 2 pole 3 wire Grounding

Not for RV



The straight 240 volt 30 and 50-amp Service looks like this. It uses a 30 OR 50-amp Double pole Breaker with Two Hot leads and a Ground. NO NEUTRAL

Welder Service is not the same as the OLD Appliance Service. Both are 3-wires but the OLD Appliance use 2 Hot and Neutral the Welder use 2 Hot and Ground. NEMA 6-30R or 6-50R

In a straight 240-volt circuit like an electric hot water heater or a welder there is no need for a neutral return. All of the energy is absorbed and used up by the elements and the welder. The Ground is VERY important for a welder to work. In case of a short in the welder's transformer/rectifier the current would quickly go straight to ground and hopefully trip out the 30 or the 50 amp breaker from overload.

The above straight 240-volt would also work on the electric stove and dryer except they need the 240-volt for the dryer and stove's heating elements and the 120-volt to run the dryer motor and the controls on the stove so they need the neutral wire. (See the Appliance Service on the left) 

DO NOT ATTEMPT TO MAKE AN ADAPTOR to plug into a 6-30R or 6-50R Welder Service. There is NO NEUTRAL in this service.  

Converting the Welder (6-30R or 6-50R) service over to a 30-amp 120-volt RV service  Remove the Double pole breaker and replace it with a Single pole 30-amp breaker. This service requires 3 wires 1 Black (Hot lead) 1 White (Neutral) and 1 Ground. One of the hot wires will have to be made into Neutral wire. Use white tape to identify it for future reference. Install a TT-30R receptacle and its ready to go. 

Converting the WELDER 6-50R (50-amp) 240-volt Service to a 14-50R 50-amp RV outlet. Since the welder service comes with 3 wires (2 HOT 1 Ground) an extra wire for the Neutral must be pulled for a 50-amp 120/240-volt 3 pole 4 wire grounding Service for an RV. The 50-amp breaker is the same, install a new 14-50R 3 pole 4 wire grounding receptacle and the extra WHITE wire. 

Converting the WELDER 6-30R (30-amp) 240-volt Service to a 14-50R 50-amp RV outlet the wire size must meet the 50-amp requirements. Replace the 30-amp double pole breaker with a 50-amp double pole breaker. Follow the direction above for the rest. Both of the above 50-amp conversions will supply 2 - 50-amp lines or 12,000 watt power to the RV.

 If the 30-amp 240 Welder Service wire size doesn't meet the 50-amp wire size ALL new wires must be pulled or make it into a 30-amp 120/240-volt service. This is the SAME service as the 50-amp Service above with 4 wires except it will have 2 - 30-amp lines or 7200-watt power to the RV. This service would be preferred in a 50-amp coach to the single line 120-volt 30-amp service. Use the 30-amp Double pole breaker already installed. 

14-30R Install a new 14-30R 3 pole 4 wire grounding receptacle and the extra WHITE wire. A home made dog bone can be made with a 14-30 PLUG and a 14-50 receptacle in order to use the 50-amp RV cord.  
ALWAYS check out new installations. Anyone can and will make a mistake.