20 amp plugs

[Dave Zellers]

Is it possible to buy a plug rated for 20 amps that has the normal configuration of 2 vertical prongs? All the ones I'm seeing have one vertical and one horizontal.

[Mike Henderson]

I think that pretty much defines a 20 amp plug.

Mike

[Dave Zellers]

OK. Since this is for 110 and not 220, I was hoping.

Follow-up question- my drum sander is 110v but supposed to be on a 20 amp circuit. Would it be a problem to use a 12 ga extension cord with a 15 amp plug to extend the 20 amp circuit? I'm making the extension box and the 2 duplex receptacles are rated 20 amp with the 15 and 20 amp configuration but if I use a 20 amp plug I won't be able to ever use this on a 15 amp circuit. Not a huge deal but I like things to be as multi purpose as possible. So would a 15 amp plug really cause any problems?

[Mike Henderson]

An appliance or tool the requires more than 15 amps will usually come with a 20 amp plug so you don't plug it into a 15 amp circuit and pop the breaker.

If you have 20 amp breakers and wire that will handle up to 20 amps, I would not be afraid to use a regular two or three prong 120V plug on the appliance or tool. But if you plugged it into a 15 amp circuit, the appliance or tool would pop the breaker.

Someone who came after you would not be put on notice (because of the lack of the 20 amp plug) that the appliance or tool required a 20 amp circuit.

Mike

[Most outlets that are 20 amp will accept either a 20 amp plug or a 15 amp plug. It's the male plug on the appliance or tool that signifies that the tool requires 20 amps. Put 20 amp outlets on your extension box and you can plug either into it. And that way you can keep the 20 amp plug on the tool.]

[Bruce Wrenn]

The 20 amp recepticals accept the 15 amp plugs. They have the advantage of gripping plugs tighter. All the 110 recpt. in shop are 20 amp, along with the ones in our kitchen. Buy hospital grade plugs, as they are the best. Unfortunately they COST a LOT MORE.

[Dave Zellers]

OK this all makes sense. The drum sander does not have a 20 amp plug on it but they recommend running it on a 20 amp circuit. I guess they are just being cautious in case other things are running on that circuit at the same time. I'll use a regular plug and not worry about it. All the wire is 12ga- the romex and the stranded extension.

[Mike Henderson]

My guess, Dave, is that the sander will draw very close to (or maybe even a bit over) 15 amps when it's bogged down and that could pop a 15 amp breaker. But under normal conditions, it probably draws less than 15 amps.

Mike

[Dave Zellers]

My guess, Dave, is that the sander will draw very close to (or maybe even a bit over) 15 amps when it's bogged down and that could pop a 15 amp breaker. But under normal conditions, it probably draws less than 15 amps.

Mike
Probably right on. Logical.

[Rod Sheridan]

My guess, Dave, is that the sander will draw very close to (or maybe even a bit over) 15 amps when it's bogged down and that could pop a 15 amp breaker. But under normal conditions, it probably draws less than 15 amps.

Mike

That could be accurate Mike, they also may have an issue with locked rotor current and needed larger overcurrent protection to start the machine.........Regards, Rod.

[Mike Henderson]

That could be accurate Mike, they also may have an issue with locked rotor current and needed larger overcurrent protection to start the machine.........Regards, Rod.

Good point. I forgot about startup.

Mike

[Art Mann]

You guys should really study up on breaker behavior. If you are familiar with using graphs, download the "trip curve" for the breaker you are using. Actually, they all behave about the same. First of all, the actual trip current of a normal breaker could be 10% or even 20% higher than the specified trip point. These are not very accurate devices. Second, most breakers will sustain twice the rated current for 20 to 40 seconds and ten times the rated current for 4 or 5 seconds. One should never oversize a breaker to compensate for startup current. That is already designed to the breaker itself. Also, momentary load peaks in excess of the trip current will seldom cause a breaker to open unless conditions are really bad - like locked rotor for an extended time.

Here is a link to some information I found doing a quick search that looks pretty good. There are dozens of references on line.

https://www.schneider-electric.us/en/download/document/0600DB0105/

[Myk Rian]

All my outlets are 20 amp, so I have no problem what I plug into them.

[Rollie Meyers]

All my outlets are 20 amp, so I have no problem what I plug into them.


But you can't plug a appliance that requires a 20A plug into a 20A branch circuit, because if it draws more then 50% of the branch circuits rating then it requires it's own circuit.

[Jim Becker]

Rollie, that's true...and also probably one of the most ignored rules, particularly in kitchens. :) My espresso machine requires a 20 amp connection (and has the plug to prove it), but the nature of such things is that it uses the regular branch circuit because that's what's there. But it also isn't operating when something else might need to use that same circuit.

[John Bullock]

I was a hospital manager for over 40 years in hospitals and as a department head was responsible for complying with safety rules and subject to sport inspections. Every hospital manager is responsible for assuring that hospital quality plugs are installed and that they meet OSHA and electrical standards. Hospital grade receptacles and plugs can easily be identified by a green dot embossed in the body of the plug or receptacle. In addition to have the identification, records are maintained certifying that such plugs require a minimum effective tension to be removed from their receptacle. This guarantees that a loose plug won't be accidentally withdrawn or fall out of its corresponding receptacle. If a receptacle does not meet the minimum standards for withdrawal of the plug, it must be replaced, even though it is otherwise working appropriately. The last thing that should ever happen is for a patient to be endangered by having a plug accidentally fall out of a receptacle

[Chuck Wintle]

I was a hospital manager for over 40 years in hospitals and as a department head was responsible for complying with safety rules and subject to sport inspections. Every hospital manager is responsible for assuring that hospital quality plugs are installed and that they meet OSHA and electrical standards. Hospital grade receptacles and plugs can easily be identified by a green dot embossed in the body of the plug or receptacle. In addition to have the identification, records are maintained certifying that such plugs require a minimum effective tension to be removed from their receptacle. This guarantees that a loose plug won't be accidentally withdrawn or fall out of its corresponding receptacle. If a receptacle does not meet the minimum standards for withdrawal of the plug, it must be replaced, even though it is otherwise working appropriately. The last thing that should ever happen is for a patient to be endangered by having a plug accidentally fall out of a receptacle

That would be very tragic indeed!

[John K Jordan]

Hospital grade receptacles ... require a minimum effective tension to be removed from their receptacle. This guarantees that a loose plug won't be accidentally withdrawn or fall out of its corresponding receptacle.

That's good to know. For the curious I found this which gives references: https://www.ul.com/wp-content/uploads/2014/04/ul_HospitalGradeReceptacles.pdf

It makes me wonder if there are also "hotel grade receptacles" made on purpose with low tension specifications. :) Several hotels I've stayed in, including a recent stay at an expensive Marriott, have had receptacles that barely held the plugs. I had to delicately support the cable of my phone charger so the little plug/power supply wouldn't just fall out of the socket from it's own weight.

JKJ

[Matt Marsh]

But you can't plug a appliance that requires a 20A plug into a 20A branch circuit, because if it draws more then 50% of the branch circuits rating then it requires it's own circuit.

A 20 amp receptacle can accept a maximum cord and plug connected load of 16 amps (table 210.21(B)(2)). I know of no other NEC article that requires an individual branch circuit for an appliance with a full load amp rating over 50% of the branch circuit rating.

[Mike Henderson]

That's good to know. For the curious I found this which gives references: https://www.ul.com/wp-content/uploads/2014/04/ul_HospitalGradeReceptacles.pdf

It makes me wonder if there are also "hotel grade receptacles" made on purpose with low tension specifications. :) Several hotels I've stayed in, including a recent stay at an expensive Marriott, have had receptacles that barely held the plugs. I had to delicately support the cable of my phone charger so the little plug/power supply wouldn't just fall out of the socket from it's own weight.

JKJ

I took a vacation to Cuba and stayed at the famous Hotel Nacional in Havana. They had the standard American 120V outlets - EXCEPT that the power was 220V. That was not a problem for my computer, which can operate on either voltage. But the outlets were so worn the plug would not stay in the outlet. Not just one outlet - all the outlets in the room.

If you go to Havana, avoid the Hotel Nacional unless you just want to experience the history of the hotel. It's ancient and badly needs renovation. There are some modern and really nice hotels in Havana.

Mike

[Jim Koepke]

That's good to know. For the curious I found this which gives references: https://www.ul.com/wp-content/uploads/2014/04/ul_HospitalGradeReceptacles.pdf

It makes me wonder if there are also "hotel grade receptacles" made on purpose with low tension specifications. :) Several hotels I've stayed in, including a recent stay at an expensive Marriott, have had receptacles that barely held the plugs. I had to delicately support the cable of my phone charger so the little plug/power supply wouldn't just fall out of the socket from it's own weight.

JKJ

Yes, "hotel grade receptacles" are the cheapest ones that can be found in the aisles of the big box and discount stores.

In home use a receptacle doesn't have many full cycles of something being plugged in and then unplugged on a regular basis. In our kitchen at most the toaster gets unplugged when its regular receptacle is needed for a mixer or Crock Pot. This is usually less than 3 or 4 times a month.

In a hotel the receptacle is likely used by most guests for charging a phone or using a laptop. When vacated the room service staff will likely use it to plug in their vacuum cleaner. If the hotel is doing well, this means the receptacle in some rooms may go through a few cycles every day. Though there may have been a few dollars saved during the construction, it may end up being a more expensive maintenance problem.

jtk

[Carlos Alvarez]

The last thing that should ever happen is for a patient to be endangered by having a plug accidentally fall out of a receptacle

Then why not use twist-lock or other more secure methods?

[John K Jordan]

Then why not use twist-lock or other more secure methods?

I suspect it is because the devices they plug in come with standard NEMA 5-15P plugs.

[Rod Sheridan]

Then why not use twist-lock or other more secure methods?

In almost 40 years of industrial experience, I've found that we have the most failures with locking receptacles/cord caps compared to straight blade devices.

I've found that "non trades" users fail to adequately rotate the locking cord caps resulting in high resistance connections and failures. Straight blade devices can be verified for proper insertion visually, by non skilled operators..........Regards, Rod.