# Name for these electrical plugs?



## Aaron_W (Jan 30, 2022)

I'm trying to find replacements for the plug on a watch  makers lathe. Simple 2 prong plug but with round pins instead of flats. 120v AC and allows the foot pedal speed control to be connected to the lathe. The ones on it work, but are quite old and I'm concerned it is just a matter of time for them. I'd also like to have the option of using a dial type speed control in the future so would need a compatible plug to do that.

Plugs are about 1" long and 1/2" in diameter with two 1/8" round pins with matching round sockets on the other half.




I've tried 120v two pole plug, 2 pin plug, round in various combinations. The closest I've been able to find are trailer plugs. I'm sure this is just a matter of knowing the right search terminology.


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## erikmannie (Jan 30, 2022)

What would happen if you replaced both of those with a more common male & female receptacle? Aren’t they just conducting electricity?

Edit: this discussion discourages that idea!









						Can I splice a standard AC power plug onto a 2-pin DIN table lamp cord?
					

I've acquired a table lamp with a 20W 12V bulb (possibly from IKEA?). The cord terminates with a female 2-pin DIN (41529) connector that I do not have an adapter for. Am I correct to assume that it...




					electronics.stackexchange.com
				




If that won’t work, you could try *taking a picture head on*, and then doing a Google image search.


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## sdelivery (Jan 30, 2022)

Check allied electronics or gallon or wolf automation. 
More then likely you will need to buy both sides the obsolete existing connector will probably be unavailable


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## matthewsx (Jan 30, 2022)

Don’t know if you’ll find it here but it‘s an interesting website.






						Museum of Plugs and Sockets: home page
					

Annotated display of 1000 domestic electrical plugs and sockets from all over the world, including classic and obsolete types.



					www.plugsocketmuseum.nl
				




John


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## Eddyde (Jan 30, 2022)

I suggest converting it to a twist lock plug and receptacle with 3 prongs, so you can add a ground wire.








						McMaster-Carr
					

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.




					www.mcmaster.com


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## jeffkash (Jan 30, 2022)

Those were used on sewing machines back in the 1960's. Maybe check your local appliance repair store.


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## Cadillac (Jan 30, 2022)

The three prong plugs in the size are called a xlr plug used in the music industry and in  battery power connections these days. They might offer in a two pin never checked.


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## francist (Jan 30, 2022)

It’s the size of the OP’s items that is curious to me. A lot of the plug connectors on my old sewing machines do indeed have a two or three pin style but they’re quite a bit larger. The OP’s are only 1/2” diameter — that’s only slightly larger than a TV co-ax cable. I did find “LEMO” connectors that are kind of close but I don’t think correct. Back to the sewing machine idea — few makes are interchangeable so a Bernina machine has to have a Bernina cord, a Pfaff pin configuration is different than a Singer, etc. I’m wondering if they weren’t a similar proprietary design for that particular power supply.

-frank


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## jeffkash (Jan 30, 2022)

francist said:


> It’s the size of the OP’s items that is curious to me. A lot of the plug connectors on my old sewing machines do indeed have a two or three pin style but they’re quite a bit larger. The OP’s are only 1/2” diameter — that’s only slightly larger than a TV co-ax cable. I did find “LEMO” connectors that are kind of close but I don’t think correct. Back to the sewing machine idea — few makes are interchangeable so a Bernina machine has to have a Bernina cord, a Pfaff pin configuration is different than a Singer, etc. I’m wondering if they weren’t a similar proprietary design for that particular power supply.
> 
> -frank


I was a sewing machine repair technician back in the 60's. My boss used to import "generic" sewing machines from the far east and mate them with US made motors. We had the two pin connectors (male and female) in bulk. My memory of 60 years ago is that they were between 1/2" and 3/4" in diameter.


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## markba633csi (Jan 30, 2022)

Proprietary design.  You might want to replace with a small Hubbell twist lock type 
Check Mouser, Digi-Key, Newark


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## RJSakowski (Jan 30, 2022)

You might try auto parts stores, farm supply stores, and marine equipment suppliers.  I have used those connectors for many years .  They come in polarized and non polarized versions.


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## Aaron_W (Jan 30, 2022)

I've tried most of the local hardware stores, but didn't think about Tractor Supply, they might have something the hardware stores don't. Might be worth a drive to Ace as well, they tend to have some more oddball stuff.

Closest I've found are aircraft plugs but they are designed for one side being fixed into a panel. It is a Bodine motor, but they don't seem to offer a motor like this anymore or any support for them. Sewing machine / appliance is the closest and they still do offer similar connections but now mostly flat plastic connections that are disposable, not replicable (surprise surprise, throw it in the trash and buy a new one).



erikmannie said:


> What would happen if you replaced both of those with a more common male & female receptacle? Aren’t they just conducting electricity?
> 
> Edit: this discussion discourages that idea!
> 
> ...



I think this would be an option, 120v on both sides so not the issue in the link where the other side was a low voltage application. Edde's idea of a twist lock would probably work to, there are some 2 prong twist locks. Aesthetically kind of clunky, like putting Super Swampers on a Jaguar but it should work if I can't find something closer to the existing.


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## matthewsx (Jan 30, 2022)

Cadillac said:


> The three prong plugs in the size are called a xlr plug used in the music industry and in  battery power connections these days. They might offer in a two pin never checked.


XLR connectors are available in different configurations but I’ve never used one for ac line voltage.

John


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## T Bredehoft (Jan 30, 2022)

The European electrical connectors are two pin, but smaller diameter pins, longer. I dunno if you want to change to something like that.... I guess I don't know what you're asking....


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## Eddyde (Jan 30, 2022)

XLR connections are for balanced audio signal, not for line voltage.


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## CluelessNewB (Jan 30, 2022)

I would guess the wires are as old as the connectors.  Replace the wires and use new connectors.   If it's all 110V AC, I would use standard NEMA 5-15  style connectors.


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## matthewsx (Jan 30, 2022)

Eddyde said:


> XLR connections are for balanced audio signal, not for line voltage.


There are many different applications, including some low voltage charging like on my dads scooter and 4 or 5 pin for clearcom headsets.

Wouldn’t want to run line voltage through one though.

John


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## Bi11Hudson (Jan 30, 2022)

You should avoid audio connectors, as mentioned above they don't handle line power very well. The connector should be rated for 150 volts or better. . . My older laptops have a 2 conductor power cable, the newer Dells have the third wire. They are recognised by some regulating authority. I don't know the exact size but they are 1/4 the size of normal line plugs. The best I can offer is to browse Allied Electronics, actually the great grand daddy of Radio Shack back in the early '60s. 



			https://www.alliedelec.com/view/search/?category=3%7C2510412%2F2816017%2F2813025&pg=6
		


I didn't look any further than page 6, there are many more. There is also listed a "fan connector" that is about the size of a lamp cord plug under the name 'Orion'. They are scattered around before and after the page given. There are many other sources that aren't "mainline" suppliers, serving some esoteric industries. As well as surplus houses, but they tend to be hit and miss one shots.

I would suggest building a 'normal' size distribution center somewhere on the backplane. With a duplex receptical where the shorting band is cut. That way, the lathe motor could plug into the speed control and a lamp into the other 'line power' plug. Way back when, I had a UniMat set up that way. Of course, the caps and plugs I used are 'outlawed' today. But the idea still serves.

.


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## Dabbler (Jan 30, 2022)

If you need to keep the compact nature of the connector, try Digi-Key electronics for a 300V or 600V connector for above the rated current.  If size doesn't matter use a UL listed domestic plug set.


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## erikmannie (Jan 31, 2022)

Eddyde said:


> XLR connections are for balanced audio signal, not for line voltage.



I use XLR connectors to connect my 36V DC eBike batteries to their 110V AC charger.


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## matthewsx (Jan 31, 2022)

erikmannie said:


> I use XLR connectors to connect my 36V DC eBike batteries to their 110V AC charger.


Yes, and you’re charging at ~39V DC, the 110V AC is the input side of the transformer.


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## matthewsx (Jan 31, 2022)

We also used XLR connectors for speaker connections in a pro audio system.


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## Eddyde (Jan 31, 2022)

erikmannie said:


> I use XLR connectors to connect my 36V DC eBike batteries to their 110V AC charger.


Sure it will work for that and a lot of other low voltage applications, but I doubt they are good choice for 120v AC. The McMaster site says 50v AC/DC @ 7A.


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## Bi11Hudson (Jan 31, 2022)

This line cord is fairly common on computers, or was at one time. It may be found by 'scrounging' for it or ordering new. It is quite inexpensive, probably cost more for shipping than the cable. It contains both connectors needed, just cut it and splice in as needed. The way I do things is to order several in case such a situation comes up in the future. That is not to recommend, just comment.  .  .

My search parameters were a little more specific this time. And the cable should be available from any number of sources.




RS Pro by Allied 1373334​
*Mfr. Part #: 1373334*
Allied Stock #: 71174033


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## John281 (Jan 31, 2022)

In addition to what's already been said, remember not to allow power on exposed pins when the connectors are unplugged from each other.  This would mean pins on the foot pedal cable.  But also consider what would happen if someone were to plug that into a standard receptacle.  For that reason, it's a good idea to use a keyed or non-standard connector.


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## Aaron_W (Jan 31, 2022)

I could have sworn I've seen this type of connector before, but it does appear to be an obsolete type. I'll take a look at the Allied Electric site, Radio Shack is where I would have gone in the past, but the local one closed a couple years ago, not sure they even exist anymore. 

I was hoping to stick with a similar look but there are modern options if I have to go that way and it is operational currently, just old and will eventually have to be replaced. The wiring is new, I already replaced the ancient dry and cracked cord.



John281 said:


> In addition to what's already been said, remember not to allow power on exposed pins when the connectors are unplugged from each other.  This would mean pins on the foot pedal cable.  But also consider what would happen if someone were to plug that into a standard receptacle.  For that reason, it's a good idea to use a keyed or non-standard connector.



Sockets end is attached to the cord and wall socket, the pins on the motor side so only energized when plugged in to the cord. Good point on not just using a standard plug though to help prevent mishaps.


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## Aaron_W (Jan 31, 2022)

For those following this I'll just ask here. I think the foot pedal is just a rheostat, what would be an appropriate switch to use to give me the option of a manual speed control if I want to set the speed and leave it rather than the foot switch. 

It is only a 1/15hp AC motor but I assume I should use something more robust than a household light dimmer switch. A lot of the dial type switches I see seem to be intended for DC.


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## jpg366 (Jan 31, 2022)

Try an image search on a PC using Google Images. Good for rounding up sources.


Sent from my iPad using Tapatalk


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## matthewsx (Jan 31, 2022)

The Edison connectors @Bi11Hudson recommended would be a good choice for your application since they are cheap and easily obtained.

The “dimmer” you’re looking for is called a variac. Here’s an inexpensive one from Vevor:









						Variac Transformer Variable 1000va Ac Voltage Regulator 110v 1kva 60hz Pro  | VEVOR US
					

Discover Variac Transformer Variable 1000va Ac Voltage Regulator 110v 1kva 60hz Pro, Pure Copper Coil and 0 - 130V Adjustable at lowest price, 2days delivery, 30days returns.




					www.vevor.com
				




John


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## Aaron_W (Jan 31, 2022)

I found these on Amazon, not a perfect match but at least they look techy. These are rated at 125v 7A, but the motor is only rated as 1.45A so thinking these should be ok?

2Pin 16mm Waterproof Female/Male Wire Panel Power Chassis Metal Fittings Aviation Connector


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## Forty Niner (Jan 31, 2022)

A bit off topic...but since you are talking about powering a watchmakers lathe, I would like to point out that the motor for your watchmaker's lathe is a "universal" type motor.  It will run on AC or DC.   I have found that these motors run much better on DC.  I have 4 watchmaker's lathes that I power with DC.   The low speed torque is especially improved using DC power.   The speed controller that is used on treadmills works fine for the application.  Treadmill motors run on DC.  There are plenty of options for converting AC to DC with speed control.


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## matthewsx (Jan 31, 2022)

Forty Niner said:


> A bit off topic...but since you are talking about powering a watchmakers lathe, I would like to point out that the motor for your watchmaker's lathe is a "universal" type motor.  It will run on AC or DC.   I have found that these motors run much better on DC.  I have 4 watchmaker's lathes that I power with DC.   The low speed torque is especially improved using DC power.   The speed controller that is used on treadmills works fine for the application.  Treadmill motors run on DC.  There are plenty of options for converting AC to DC with speed control.


Yep, I have a cutter/grinder that I actually run with a lamp dimmer. A variable voltage dc power supply might be an excellent choice.

John


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## tq60 (Jan 31, 2022)

Eddyde said:


> Sure it will work for that and a lot of other low voltage applications, but I doubt they are good choice for 120v AC. The McMaster site says 50v AC/DC @ 7A.


Common for wheel chair chargers, 3 pin, plus, minus and the other shorted to one or the other tells controller that charger is plugged in.

Sent from my SM-G781V using Tapatalk


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## Aaron_W (Jan 31, 2022)

Forty Niner said:


> A bit off topic...but since you are talking about powering a watchmakers lathe, I would like to point out that the motor for your watchmaker's lathe is a "universal" type motor.  It will run on AC or DC.   I have found that these motors run much better on DC.  I have 4 watchmaker's lathes that I power with DC.   The low speed torque is especially improved using DC power.   The speed controller that is used on treadmills works fine for the application.  Treadmill motors run on DC.  There are plenty of options for converting AC to DC with speed control.



Here is the tag, it looks like you are right it is a universal motor.





Are you suggesting something like this to run it?

3V - 24V 1.5A 36W Adjustable DC Power Supply Kit AC Adapter Speed Control Volt Display


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## matthewsx (Jan 31, 2022)

I don’t know how many volts for how many rpm, might be worth some research there.


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## matthewsx (Feb 1, 2022)

If you have an old laptop power supply you can find out what 19 volts does.


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## CluelessNewB (Feb 1, 2022)

A router speed control would probably work just fine for that.  The cheapest is probably the one sold by Harbor Freight at $15, better ones are available for more money.  I have one I built from an EICO kit back in high school in the 1970s.  It still worked last time I used it a couple of years ago.


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## CluelessNewB (Feb 1, 2022)

Although personally I would not use it, the "COLE HERSEE M-121-BP" connector is similar to your original.  It's sold by many marine supply stores.  

Here is one source: 
https://www.defender.com/search.html?q=M-121-BP


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## Shiseiji (Sep 11, 2022)

Late, but the sewing machine reference = what was called a General Electric connector used on some Singer cabinets so the foot pedal could be removed and stored in a drawer. One was an art-deco cabinet that was also a writing desk complete with an ink well in a drawer. Have one in my collection.

Ron


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## Bi11Hudson (Sep 12, 2022)

Not having read the entire thread, there may have been a solution presented that I am not aware of. Many older types of connections have been "obsoleted" for safety reasons. Cords with metal covers will be very difficult to find new.

Might I suggest something of the nature of a "dime store" 2 wire lamp extension cord with a "non-standard" plug-cap configuration. Most modern sewing machines use a series universal motor with an electronic gizmo to control speed. An "old style" resistive foot pedal is rare today. What you are looking for will be on the order of an automotive trailer connector that has 2 conductors and is *rated for 120/240 volts*.

I include a couple of links to suppliers of electrical or electronic components. The big issue with them is that they carry many *connectors not rated* for 120 or 240 volts. Care should be taken that most "audio" devices are not so rated. Motor current will probably not be an issue, a small motor such as yours will not draw much, 2 amps at the outside. 









						5' 2 prong ac power cord | MPJA.COM
					

5-1/2ft,18-2AWG IEC Class II type power cord. 250VAC/6A Max. 2 blade Non-polarized molded plug on one end, 2 socket,  rounded edges with dimples on 2 sides, female notebook/laptop/Audio/TV equipment plug on other. Black jacket.



					www.mpja.com
				









						Circular Connectors, Circular Cable Power Connectors - Allied Electronics & Automation, part of RS Group
					

Search results for Circular Connectors, Circular Cable Power Connectors - Allied Electronics & Automation, part of RS Group.




					www.alliedelec.com
				






			https://www.digikey.com/en/products/filter/pluggable-connectors/443?s=N4IgjCBcoBwAwWiAxlAZgQwDYGcCmANCAPZQDaIAzDAOwxhwhHU0Cc9IAukQA4AuUEAGU%2BAJwCWAOwDmIAL5EAtACYooVJDEBXQiXIgArFzkmgA
		


.


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## pontiac428 (Sep 13, 2022)

Jeez, all you need is a plug that can carry the max amperage that the motor can draw.  Mouser, DigiKey, McMaster, pick whoever you want, and find a M/F pair of adequate plugs.  It's not a restoration or a rocket ship, right?  You can get Canon/ITT/Deutsch plugs with 3/8" solid pins that can power a 260-series International truck starter.  You can literally open any number of catalogs and pick something that will work.  I chose Speakon connectors for my stepper motors because they are cheap, common, and adequate for the load.  I didn't start a thread on it, because it's as mundane as finding a bolt to fit a threaded hole.  Does it fit?  Is it adequate?  Great! Next project!

Sorry in advance to @Aaron_W.  I'm playing the devil's advocate/reality check guy here, and I'm at a loss to being constructive.  I have every confidence you will find what you need to provide disconnectable power to your sub-1.5A motor. Lots of companies supply parts to connect two wires together.  My constructive advice is to get out and look.


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## Bi11Hudson (Sep 13, 2022)

The "big issue" involved here is to avoid a connector for anything, such as a lamp or appliance, that can plugged into the female end. It won't cause a short, just putting something is series with the motor. But will possibly cause a great deal of confusion when it happens. In a *worst case scenario*, using a piece of wire across the cap will cause the motor to run at full speed.

.


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## pontiac428 (Sep 13, 2022)

I would certainly be confused if I plugged my table lamp into my soldering iron and it caused music to come out.  I mean, the garden hose sure fits in the oil fill cap on my car like it was meant to, but I'm not putting the two together.  Now, I don't know how to prevent anyone from plugging my HAM radio into my sewing machine by way of my wife's Mixmaster, but that's just one too far.  Better hard wire it.


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## Aaron_W (Sep 13, 2022)

pontiac428 said:


> Jeez, all you need is a plug that can carry the max amperage that the motor can draw.  Mouser, DigiKey, McMaster, pick whoever you want, and find a M/F pair of adequate plugs.  *It's not a restoration or a rocket ship, right?*  You can get Canon/ITT/Deutsch plugs with 3/8" solid pins that can power a 260-series International truck starter.  You can literally open any number of catalogs and pick something that will work.  I chose Speakon connectors for my stepper motors because they are cheap, common, and adequate for the load.  I didn't start a thread on it, because it's as mundane as finding a bolt to fit a threaded hole.  Does it fit?  Is it adequate?  Great! Next project!
> 
> Sorry in advance to @Aaron_W.  I'm playing the devil's advocate/reality check guy here, and I'm at a loss to being constructive.  I have every confidence you will find what you need to provide disconnectable power to your sub-1.5A motor. Lots of companies supply parts to connect two wires together.  My constructive advice is to get out and look.



It is sort of a restoration.  Lots of options for functional, but it is for a 100+ year old watch makers lathe so I was initially hoping for something that looked at least sort of period correct. At this point I think I'm down to functional and aesthetically pleasing. 

I've barely been home since the beginning of April so I haven't gotten anywhere on this yet, but there have been many possible solutions suggested.


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## Dabbler (Sep 13, 2022)

Aaron, I think is a great idea to make it right for you and consistent for the type and period.  You might try antique stores.  If the wires are frayed, you can often get electrical tidbits at low prices, and might look quite authentic.  Most plugs before the 50s were just brass or bronze, and not nickel plated.  These are easy to clean and reset for proper contact.


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## Aaron_W (Sep 13, 2022)

Dabbler said:


> Aaron, I think is a great idea to make it right for you and consistent for the type and period.  You might try antique stores.  If the wires are frayed, you can often get electrical tidbits at low prices, and might look quite authentic.  Most plugs before the 50s were just brass or bronze, and not nickel plated.  These are easy to clean and reset for proper contact.



I did have to replace the wiring, but the old wiring was just lamp cord, dry and brittle, it was certainly not original to the lathe either. Modern lamp cord was nearly identical, to the old, just not dry and brittle. 
This lathe came from the estate of the owner of a local but long out of business jewelry and watch repair shop so it is in pretty decent shape other than sitting for who knows how long.


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## Eddyde (Sep 14, 2022)

pontiac428 said:


> I would certainly be confused if I plugged my table lamp into my soldering iron and it caused music to come out.  I mean, the garden hose sure fits in the oil fill cap on my car like it was meant to, but I'm not putting the two together.  Now, I don't know how to prevent anyone from plugging my HAM radio into my sewing machine by way of my wife's Mixmaster, but that's just one too far.  Better hard wire it.


It is a legitimate issue. That's why electrical connectors come in so many configurations, to prevent accidents. It might be obvious to the current user not to plug something else into it but machines usually outlive their owners and who knows what will happen to it in the future. IMHO it's good practice to make things mistake proof as possible, especially electrical connections.


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