240 Plug Type

[shubox56]

Hi GJ,

I will be adding a 240 circuit to my breaker panel in Feb and have a question about plug types. The addition of this 240 outlet is forward looking, something I will use in the future. Things like an air compressor, or maybe a small welder. Not knowing what the plug requirement will be at this time, is this something I could address with adapters regardless of the outlet installed? Are there adapters to convert most all plug types?

Many thanks!

 

[brownbagg]

you got four type of 240 plugs,

one is a round locking plug, its only use in industrial, so that out
two are four prong
one is three prong

if you have an aplliance that has a 110 circuit like a clock, its use four prong because it needs a netural ( stove range, dryer, etc)

no 110 circuit, three prong, that the welder plug which is the same for air compressor

that it, you need a three prong

 

[shubox56]

you got four type of 240 plugs,

one is a round locking plug, its only use in industrial, so that out
two are four prong
one is three prong

if you have an aplliance that has a 110 circuit like a clock, its use four prong because it needs a netural ( stove range, dryer, etc)

no 110 circuit, three prong, that the welder plug which is the same for air compressor

that it, you need a three prong

So something like a NEMA 6-20P? If I go with a 20 amp breaker? Have not looked at the 30a plugs yet.

 

[Stuart in MN]

Without knowing the ampacity of what you may plug in to the receptacle, you'll just be guessing on what to install. Also note that there's a limitation on how big a motor (in horsepower) that you can plug into a standard type of receptacle.

 

[u2slow]

Hi GJ,

I will be adding a 240 circuit to my breaker panel in Feb and have a question about plug types. The addition of this 240 outlet is forward looking, something I will use in the future. Things like an air compressor, or maybe a small welder. Not knowing what the plug requirement will be at this time, is this something I could address with adapters regardless of the outlet installed? Are there adapters to convert most all plug types?

Many thanks!

Tell you what I did....

My welder and compressor both use a 20A 240V circuit. I put three 6-20R receptacles around the shop. Also made up my own 6-20P to 6-50R cord (about 10') for my welder. Use one at a time of course.

 

[justinthurn]

If you want to be certain you can run things you don't know u want, wire in nema 14-50 with 6gauge wire. You can use adaptors to go down from there.

Sent from my SM-G960U using The Garage Journal mobile app

 

[sberry]

If you want to be certain you can run things you don't know u want, wire in nema 14-50 with 6gauge wire. You can use adaptors to go down from there.

Sent from my SM-G960U using The Garage Journal mobile app

No, you cannot or should not use adapters. If a tool comes with a 20 or 30 end then that's the circuit limit it is to go on. 20 to 50 for a welder is no problem but no adapters for 50 down with one exception for rv which this isnt.

 

[matt_i]

Some small welders come with a 6-50 straight blade "oven plug".

You can easily go to a box store and buy an "appliance whip" or "appliance cord" which is a male plug with a cord attached which is about 3ft long. Buy the one with the same end, then you can wire this to your air compressor.

There are some specific rules for air compressors due to the potential for unplugging the motor under load and generating an arc flash, you will find out them in the Electrical section of the forum.

As suggested above I would wire #6 THHN in conduit, then you are never going to be short of amperage.

 

[shubox56]

No, you cannot or should not use adapters. If a tool comes with a 20 or 30 end then that's the circuit limit it is to go on. 20 to 50 for a welder is no problem but no adapters for 50 down with one exception for rv which this isnt.

I'm not sure that I follow. Why couldn't a 20A compressor (or whatever) run on a 50A circuit with an adapter (going down in amperage, not up)? The breaker is matched to protect the wire and the device is pulling what it needs which will be far less than 50A.

BTW, thanks for the education.

 

[shubox56]

Some small welders come with a 6-50 straight blade "oven plug".

You can easily go to a box store and buy an "appliance whip" or "appliance cord" which is a male plug with a cord attached which is about 3ft long. Buy the one with the same end, then you can wire this to your air compressor.

There are some specific rules for air compressors due to the potential for unplugging the motor under load and generating an arc flash, you will find out them in the Electrical section of the forum.

As suggested above I would wire #6 THHN in conduit, then you are never going to be short of amperage.

The whip idea is something I was considering. Thanks for the input.

I don't want to add a 50A circuit to my 100A breaker box, but I could add a 30A circuit. It's not likely that I will exceed 30 amps. Better idea? And which outlet would be best overall to install?

I hate 240! The lack of 110-like uniformity is frustrating.

 

[MushCreek]

Hmmm- I have three different types. A 6-20p for the compressor (that's what it came with), a 50A RV-type plug for the welder, because that was the cheapest way to get a big cord for the welder (it didn't have one), and several twist-lock 3 phase outlets for, well, three phase equipment. I don't see the problem with different plugs for different equipment. The compressor circuit is way too light for the welder, the welder circuit is way too big for the compressor, and the three phase is self-explanatory.

 

[shubox56]

Hmmm- I have three different types. A 6-20p for the compressor (that's what it came with), a 50A RV-type plug for the welder, because that was the cheapest way to get a big cord for the welder (it didn't have one), and several twist-lock 3 phase outlets for, well, three phase equipment. I don't see the problem with different plugs for different equipment. The compressor circuit is way too light for the welder, the welder circuit is way too big for the compressor, and the three phase is self-explanatory.

Maybe I'll just focus on the compressor to simplify things. Install a 6-20P outlet on a 20A breaker and call it a day. Worry about the welder in the future *if* I add a welder.

 

[shubox56]

Hmmm- I have three different types. A 6-20p for the compressor (that's what it came with)

Out of curiosity, what compressor are you using. Because I'm looking for a good 240V compressor that can run on a 20A circuit. Moderate use, nothing industrial. Something that would use a 6-20P plug.

 

[sberry]

I would be interested it seeing which welders come with a "oven" plug. But you could add a 10 wire 30 breaker for future welder. Modern welders now run on 30A service but come with 50 ends to allow them to be used on 50A circuits and are designed for it.
The reason you do not run 20 on a 50 for other equipment is that it isn't designed for it, equipment that runs on 20 may have as light as a 16 cord, limited to 20 breaker, 14 cord limited to 30. The internals of the machine are not rated to be connected to larger circuits.
There is no reason you need a number 6 wire circuit and highly unlikely you will ever need a 50A breaker unless you add a buzz box or 250 mig welder, a buzzer will run from 10 cable 50 circuit as will a 250 under limited circumstances found in home type shops. Given the changes in modern welders I wouldn't have either unless I had to.

 

[sberry]

If you want to future proof for compressors use a piece of 8 cable. New welders can run 12 cable 30 breaker. There are comps run from 20 but they are pretty wimpy, a 10 cable would be better but so many are now 5 hp and call 8 in cable,, if this is pipe then they can use a size smaller. Many are now coming with motors listed as "special" of some type to get around the horsepower rating requirements which allows them on 10 cable circuits.

 

[sberry]

If you used 10 wire could use a 20 or 30 breaker. If you use 12 will be limited to 20 if it is cord and plug connected.

 

[shubox56]

If you used 10 wire could use a 20 or 30 breaker. If you use 12 will be limited to 20 if it is cord and plug connected.

Which makes sense to me. Pull a 10G wire regardless if I go with a double-pole 20 or 30A breaker. Swamping a breaker is the easy part.

 

[CraigStu]

Which makes sense to me. Pull a 10G wire regardless if I go with a double-pole 20 or 30A breaker. Swamping a breaker is the easy part.

Exactly. I'd run the 10G wire and install a 20A breaker. If it ever starts popping, once you verify all is well you can swap in a 30A breaker. Maybe 20 yrs ago I was talking w/ an electrician about this type situation and he said one thing I have always remembered.
You don't want your romex inside the wall to be your fuse.
As we all know it's easy to replace a breaker. I am sure there have been 1000s of 20A breakers replaced by a 30A but wire is sized for the 20A. You will not have that problem starting w/ the 10G wire.

 

[sberry]

I am waiting so this is piecemeal. Copy and paste is something I need to master from phone. But from above,, fuse in the wall is good but it's rather simplistic. Really true for general circuits, some dedicated like a heater that might have the potential to run continious.
The breakers main function.on dedicated and single outlet is for short circuit interuption, both

 

[shubox56]

I am waiting so this is piecemeal. Copy and paste is something I need to master from phone. But from above,, fuse in the wall is good but it's rather simplistic. Really true for general circuits, some dedicated like a heater that might have the potential to run continious.
The breakers main function.on dedicated and single outlet is for short circuit interuption, both

Wrong thread I'm guessing.

 

[sberry]

Ok, back. Short circuit both in the circuit wire but for the cord and any/many internal components until there is additional if any further protection.

 

[sberry]

All the listed equipment designed to plug in to general circuits is designed this way as are fixtures. Limited to 20A for fault protection which is different than thermal overload,, overheating the wire.

 

[matt_i]

It looks like a lot of the newer welders are 120/240vac and auto-range with a variety of cord ends that adapt.

A 120vac machine while simpler to power, does limit you.

 

[sberry]

Only ones they come with are 5-15 and 6-50. Auto range and DVI are different. Its been a while since I went thru it,,, so,,, fwiw I think the others don't even come with ends, some might be with cords. But don't quote it as gospel.

 

[u2slow]

Out of curiosity, what compressor are you using. Because I'm looking for a good 240V compressor that can run on a 20A circuit. Moderate use, nothing industrial. Something that would use a 6-20P plug.

I have a Speedaire 1NNF7...
( https://www.grainger.com/product/SPEEDAIRE-3-0-HP-1NNF7 )
Campbell Hausfeld and others make the same thing. Also stationary uprights available in 3hp. They put out about 10cfm.

My Millermatic 211 works on the same 20A/240V circuit.

 

[sberry]

Yes, the welders seem to work on 20A breakers. Not sure how long of duty cycle they might tolerate. I had a 140 in the shop and could turn it up to 23 or 24A and didn't trip up a 20. I didn't run it long, it was just a test. The 180-210. 22 to 24A input peaked right out with 030 solid.
My tailor made home circuits for them are 10/30 for the 240v.

 

[sberry]

I was wiring something for the neighbor. He had an idea for the outlet but I can see the future, put 8t here and I gonna have this big ole cord. I added another one. He had 100 ft of 12 AC and I split it and home ran it to a 30A breaker. He seems to think it all can be wired after the fact behind the walls. But he has modern machines, a 175 feeder and a 200 synch or multi, something like that.
But for most people the only branch circuits most would need is electric range and 50RV if they have one. Most the rest of a comfy life can live from a 10 cable unless they have a 5 hp comp or 250 wire feed and even then it wouldn't burn the place down.

 

[sberry]

I was wiring something for the neighbor. He had an idea for the outlet but I can see the future, put 8t here and I gonna have this big ole cord. I added another one. He had 100 ft of 12 AC and I split it and home ran it to a 30A breaker. He seems to think it all can be wired after the fact behind the walls. But he has modern machines, a 175 feeder and a 200 synch or multi, something like that.
But for most people the only branch circuits most would need is electric range and 50RV if they have one. Most the rest of a comfy life can live from a 10 cable unless they have a 5 hp comp or 250 wire feed and even then it wouldn't burn the place down.