I am installing a 240v outlet in my garage. I want this outlet to be multi functional. I want it to run my current 100a 120v Welder and be ready for me upgrading to a bigger 240v welder when I want to. I also want to plug in my 30a RV plug into and be ready for my newer RV with a 50a plug. Of course I don't want these all running at the same time. Just one at a time. I am planning on using a 4 prong 14-50R outlet. Which is what is used for 50a RV plug. I plan on using adapters to fit any other 240v or 120v needs. 3 or 4 adapters should handle just about any plug combination I run into.

Are there any flaws to this plan?


skeeter

 

No such thing.

MANY flaws. You can't connect your 30A RV cord to a receptacle protected at 100A.
Connecting any 120v devices to an adapted 240v receptacle is asking for trouble.

You will need a sub panel there with several breakers and the correct receptacles.

 

PJmax,
I respect your knowledge on this site but 50a RV campsites use the 14-50R outlet. It provides 50amps on each 120v leg. When using an adapter for 30a campers it uses only one leg for the 120v and the camper is protected by a 30a main circuit breaker in the camper. I myself have done it many times. So what is so unsafe about this standard practice?

skeeter

 

A 50A motor home plug and cable would be connected/protected by a 2P50A breaker.
Still not correctly protected by a 100A breaker.

 

Ok, am I missing something here? A normal 4 prong 240v 50a 14-50 socket is essentially only protected by a 2P50a breaker. Not a 100a breaker? Am I thinking this wrong?

skeeter

 

Yes...... it is a 2P50 breaker. 50A per leg.

 

Is the 100 amp of the welder the output? What is the duty cycle.and what does the cord end look like?

 

My Lincoln 100amp DC welder, 20% duty cycle uses 120v 20a plug. But 240v welders use several types of plugs, the most commonly the 10-50 or 10-30.


skeeter

 

The 14-50R seems to be the newest style plug that includes a ground for an added safety factor, otherwise the same as the 3 prong.

skeeter

 

So why wouldn't it be ok to have the best safest receptacle and use adapters to bump down to the different types of 3 prong outlets?


skeeter

 

Unlike what you might see at a boat marina, the rules for homes won't allow similar "conversions". If you breaker at 50Amps, then the wire plugging into the 240V recept must be good for 50 Amps.
If, what you want, is a "universal" system of 120V/20A, 240V30A, and 240/120V-50A, then will need to have upstream breakers of those values, and have independent feeds.
What you might consider is a subpanel, with a 50 or 60A feeder, and have various receptacles feed from this new panel, each with its correctly sized breaker.

 

I would also recommend installing a small sub panel and run a 50 or 60 amp 120/240 volt feeder to the sub panel. Then next to the panel install all the different outlets you need for the equipment you want to connect to it.

A 50 amp RV receptacle will work fine for the RV(s) and welder if you change the plug configuration of the welder cord to match the RV. That would make more sense then changing the RV cord as that would mess you up when camping with hookups. Just wire the welder cord cap without the neutral connection. For the smaller welder a standard 120 volt, 20 amp receptacle should work fine.

A small sub panel and material will only cost an extra $50-$100 but will give much more flexibility the just a single 50 amp receptacle.

 

Think you might be right. Why have different adapters to fit. Just change what ever equipment cord end to match the 14-50 receptacle. Not like I am going to have a dozen pieces of equipment to run.

Toljn,
You mentioned wiring the welder plug without the neutral. Wouldn't you use the neutral but not the ground?

skeeter

 

No. You always use the ground as it is there for safety and does not carry current. Every welder I have seen use straight 240 volts, not 120/240 like you have on an RV (or dryer and range) so there is no need for the neural.

 

Interesting.... guess when I get to that point I will verify with the manufacturer the correct wiring procedure. Thank you

skeeter