Alkin W31 Compressor question

[Doc Harry]

The plug we use is the NEMA 6-15 or 6-20 plug. That is the standard single phase 220v-250v, male 15 amp plug or the 20 amp plug. This plug is exactly the same size as a 110v-120v plug but the hot wires are horizontal on the 220v instead of vertical as on the 110v-120v plug. You do not need a 50 amp dryer plug for a compressor that draws 12.7 amps or less running.
That is a very common outlet here in America and if you have a special need just let me know prior to the sale and we will help you with it.
The other manufacturors do not put a plug on there at all. We include the plug, on / off switch, hour meter and cord at no charge and we will put pretty much any plug you want on there if you just tell us what you want.

Most of the confusion was in one of the original posts there was a picture of some foreign plug and definatly NOT what we use. look up NEMA 6-15 plug and I may try to post a picture of one tommorow. Most of you have one of those plugs in your garages already.

Bruce

Thanks for the answer, Bruce! Sorry I am new to all of this stuff.

I was unable to find a photo of the appropriate NEMA plug on the Internet, hence the next best thing was the photo in my OP.

I addressed my question about the plug to "technical support" at AireTex. Did I get a compressor meant for Europe? No, AireTex told me they installed the NEMA plug in Texas for the USA market.

My next question was: "Where in the USA is this plug commonly used? Is the outlet common in industrial or commercial settings? Is this something that a dive shop would be able to just "plug and play" in a commercial space?"

The answer was, "no," they couldn't think of anywhere this plug is commonly found. You had to install a NEMA outlet or get an adapter to use it in your dryer outlet.

My next question was, "If you're going through all the trouble to install a plug, why not install a plug that everyone can use right out of the box?"

You see, I don't know anyone who has a NEMA 6-15 or 6-20 outlet readily available in their home, but I know that just about everyone has a regular ol' dryer outlet ready to go.

I understand the part about the 15-amp versus the 50-amp outlet. Makes sense now that you explain it. But if you're going through all the trouble to install a plug, why not install a plug that everyone can use right out of the box without buying adapter or installing a new outlet? Do most people install a new circuit breaker in their electrical box and run wires to their garage to install a 15-amp NEMA outlet?

I've got my compressor up and running now, so it's just curiosity now.

Thank you.

 

[rcontrera]

All good questions and probably why neither Bauer nor Coltrisub install plugs as a standard measure on their compressors. The little 115 VAC compressors draw about 29 amps so they can't use a standard household outlet since they are usually rated only for 15-20 amps. When I get a 220 from Europe, they have the "Schuko" Euro plug installed and it has to be cut off so something else can be wired in. Bruce is just going one step further than I am and installs something on the end of the cord that is probably standard in his neck of the woods.

By the way, if you buy a dryer from our local Sears, they have a choice on which 220 power plug you want with it.

So, there really isn't a national "standard" when it comes to anything but lamp cords!

Just my $.02

 

[pescador775]

Since 2002, building codes have required a four wire (four prong) "dryer" plug. This is a new national standard. Older installations are three wire and are grandfathered. The four wire setup is an attempt to make the installation idiot proof or lightning proof or something. Good thing, probably. Anyway, in the three wire, the dryer box is grounded by a strap which connects to neutral. The four wire uses a dedicated ground wire separate from neutral to do pretty much the same thing.

 

[The Curly One]

The NEMA 6-15 or 6-20 plugs are the most common lower amperage plugs. The dryer plugs are 50 amp and not really the same or reccomemended.
You want the breaker to be sized small enough to trip and protect the house in case of a problem. If you put a small motor (10-20 amps) on a 50 amp dryer plug with a 60 or 70 amp breaker it would not give you any protection. What if something happened and the motor burns up or shorts out? If you have the correct size breaker it kicks off quickly and shuts off power to motor. if you have too big of breaker then it will not trip breaker and could cause big problems or a fire.
While you are right that most people have a dryer plug in their house and you could easily make an adaptor for it. The right way to do it is to use the correct plug, wiring and breaker.
The correct and most common plug for a 12.7 amp 220v motor is NEMA 6-15 or 6-20 with a 20 amp breaker. Putting a 6-50 amp plug with a 60 amp breaker is not reccomended by us.
I will talk to my people and explian it again as maybe someone talked to one of my new guys and they did not know. Thanks, Bruce

 

[skippy31]

The plug you use should be rated to at least the size of the breaker used. Using a plug rated higher than the breaker would be OK, it usually just means your paying more for the plug and wire.

The breaker MUST be rated appropriately for the device being used (or as recommended by the manufacturer). Using an inappropriately sized breaker on any load is just plain dangerous.

Skippy31

 

[pescador775]

For those just joining here are pics of the "mystery plugs", NEMA 6-15 and 6-20. This discussion prompted a check of my own system; 5hp motor, dryer plug/socket and 30 amp breaker. Been awhile since I thought about this stuff so it is good to hear what other folks are doing. If a breaker is deemed too large it should not be a big deal to pop in a smaller one. Be mindful that electric motors may have a startup surge requirement.

 

[Doc Harry]

Okay, a doctor I AM. An electrician I AM NOT.

I think I REALLY get it now. The issue is not the amps of the PLUG - the issue is the amperage of the CIRCUIT BREAKER in the electrical box. A regular dryer plug is not installed because the 50-amp dryer circuit breaker is too high. Why didn't someone tell me?

I removed the cord from my compressor and installed a regular dryer plug using wire rated for 15 amps. The dryer outlet wasn't connected to anything in the electrical box, so I had the electrician install a 15-amp circuit breaker for the compressor. So I did the right thing without even knowing why?

Pray for me. If you hear a loud explosion or see flames lighting the night sky - it's probably me and my compressor.

 

[pescador775]

Relax, Harry, all kinds of appliances with different ratings are plugged into sockets every day. The breaker is there mainly to protect the house wiring, including extensions, from melt down. In other words, to prevent a sustained current in excess of the ability of the wire to carry it without smoking. That includes the wire connection to the appliance (eg compressor). A heavy wire such as 50 amp rated dryer plug has less resistance and is less likely to be damaged regardless of breaker size. A smaller breaker, one slightly above the motor rating, is usually recommended to protect the motor. A short circuit in the motor windings could smoke the motor but even with a 60 amp breaker is not likely to cause a larger fire unless the motor is located near a flammable substance like curtains, drapes or volatile substances. Boat engine compartments may contain various electric motors and these are fuzed with values close to the motor rating to prevent heat or fire in the bilge area. You know, gas fumes and all.

 

[The Curly One]

Harry, It appears you did the right thing although maybe taking a longer, more expensive route to get there.
I did talk to my people out in the shop and they said they remember something on the phone call. They said your electrician had never seen a plug like the 6-15 and did not want to use it? Wow! That is a common plug and every Home Depot or Lowes has them in stock and every electric supply house stocks them and has a chart on the desk showing all of the NEMA plugs....... I have bought 2 different small welders from different manufacturors and both had that plug on there from the factory. That is the outlet that is in my garage and one of the outlets in my shop when we moved in there.
Every plug is identified with the NEMA number and a quick internet search would take him right to it. look up NEMA plugs and then choose your amp rating and that is the plug it brings up. More important than the plug size is that you got the right size breaker on there and the wiring in the wall is the correct size or atleast above minimum requirements.
This thread already had 5 pages before I knew about it or I would have joined in the discussion earlier. A very long drawn out discussion simply to say use the correct plug, wiring and breaker to protect your interests.
Pescador and Skippy- Thanks for your help. Maybe the picture helps everyone to understand it is a common American plug and used for that amperage. The original posting picture was of a completely different European plug. You are also correct in that you can use larger wire but should not use larger breaker.
Harry, you are right about the issue being the breaker more than the plug.

All of this is exactly why we use the NEMA 6-15 and do not put a 50 amp dryer plug on there. I do not want someone plugging a 12 amp appliance into a 50 amp circuit as you could have very big trouble before it would ever trip breaker. Plus there are actually many different dryer plugs used.
One other reason we use the 6-15 is because the female outlet for the 6-20 is designed to use the 6-15 and the 6-20 but the 6-20 plug will only fit the 6-20 outlet. (see the picture Pescador posted)
Now that you have the correct breaker I am not concerned about which plug you use. whatever works best for you as long as it is safe.

We put the NEMA plug recommend on there at no charge. You may use a different plug if you desire but should still have the correct breaker for it regardless of plug you choose.

Thanks, Bruce

 

[stammster]

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