NEMA 10-30R

[Little Bill]

Can you use the "W" (3rd wire) of a NEMA 10-30R receptacle for an EGC?

 

[Little Bill]

Can you use the "W" (3rd wire) of a NEMA 10-30R receptacle for an EGC?

To add to this, I don't know what is intended to be plugged into this outlet, someone sent a message and picture of the outlet wanting it installed. I'm just trying to see if it can be used if whatever is connected to it only needs 240V with no neutral, using the 3rd connection for an EGC.

 

[iwire]

Nope, a NEMA 10-30 is really only good for existing electric dryers. 2 hots and a neutral. No EGC.

 

[Little Bill]

Nope, a NEMA 10-30 is really only good for existing electric dryers. 2 hots and a neutral. No EGC.

What about a welder or plasma cutter?

 

[iwire]

What about a welder or plasma cutter?

Would it work? Sure.

Would it be code compliant? IMO no.

For the items you list you should use a NEMA 6-30

Here is a 'dryer' plug NEMA 10-30, 125/250 Volt, 30 amp

Here is a NEMA 6-30, 250 Volt, 30 amp

Notice the dryer plug has a neutral not a ground and the other one has a ground but no neutral.

 

[Little Bill]

Would it work? Sure.

Would it be code compliant? IMO no.

For the items you list you should use a NEMA 6-30

Here is a 'dryer' plug NEMA 10-30, 125/250 Volt, 30 amp

Here is a NEMA 6-30, 250 Volt, 30 amp

Notice the dryer plug has a neutral not a ground and the other one has a ground but no neutral.

Yes I knew the 10-30R was made for a neutral. I have a prospective customer that wants a receptacle installed for a 3 in 1 plasma cutter. I believe it is a tig welder, arc welder, and plasma cutter. Apparently, he has this recep. and wanted it connected. I had to drill him to get the info from him as to what he was going to plug into it. I was pretty sure that was the wrong recep. but need to prove to him. I will try and get the nameplate ratings and post them for some input there.
Thanks

 

[Little Bill]

Here is the info that I came up with on the welding/plasma cutter.

[FONT=Arial, Helvetica, sans-serif][FONT=Arial, Helvetica, sans-serif][FONT=Arial, Helvetica, sans-serif][/FONT][/FONT][/FONT]

Technical Details​

Input Voltage(V)​

Input Capacity(KVA)​

No-load loss(W)​

AC220V/110v+15%50/60HZ​

7.1​

40​

Efficiency​

Class of Insulation​

Case Protection Degree​

85​

B​

IP21​

Current Range(A)​

No-load Voltage(V)​

Working Voltage(V)​

TIG: 15-200 MMA: 15-200 CUT: 20-50​

TIG: 62 MMA: 62 CUT: 250​

TIG: 18 MMA: 28 CUT: 135​

Weight(kg)​

Rated Output Current(A)​

Arc-leading​

18​

TIG: 200 MMA:200 CUT:50​

TIG: HF MMA: Touch CUT: HF​

Rated Duty Cycle(%)​

Power Factor​

Cut Thickness(mm)​

60​

0.93​

CUT: 1-16​

Input Current(A)​

​

​

TIG: 21 MMA: 32 CUT: 28.6​

​

I may have this wrong, but it looks like I would need conductors for 25-30A and up to a 50A breaker. Is this anywhere close?

 

[kwired]

Would it work? Sure.

Would it be code compliant? IMO no.

For the items you list you should use a NEMA 6-30

Here is a 'dryer' plug NEMA 10-30, 125/250 Volt, 30 amp

Here is a NEMA 6-30, 250 Volt, 30 amp

Notice the dryer plug has a neutral not a ground and the other one has a ground but no neutral.

Similar problem we run into on farms around here involves 10-50 receptacles. Virtually few of them actually have any neutral load involved and really should be 6-50 receptacles. Some really old stick welders are still around and they actually have a 10-50 plug on them.

It was common practice many years ago to use 10-50 receptacles to plug in portable augers for loading or unloading grain. Now when they build a new bin whether on site with existing bins or on a new site they want to use the same portable auger at multiple sites. If you put in a 6-50 receptacle you are an idiot for doing so because now the auger will not plug in at all sites where it will be used. If you tell them they need to change the receptacles at all other sites you will be told how many years the other one worked, never with a problem.

I don't worry about it too much though. The only thing I can ever recall seeing actually use the third wire as a neutral on one of these is an electric range. I have never seen an electric range used at a grain storage bin. For the welder outlet scenario I usually make sure I'm not using a metal raceway as sole EGC just in case, but can't recall ever seeing a range in a shop either unless in a separate room with a kitchen type area.

 

[Little Bill]

Similar problem we run into on farms around here involves 10-50 receptacles. Virtually few of them actually have any neutral load involved and really should be 6-50 receptacles. Some really old stick welders are still around and they actually have a 10-50 plug on them.

It was common practice many years ago to use 10-50 receptacles to plug in portable augers for loading or unloading grain. Now when they build a new bin whether on site with existing bins or on a new site they want to use the same portable auger at multiple sites. If you put in a 6-50 receptacle you are an idiot for doing so because now the auger will not plug in at all sites where it will be used. If you tell them they need to change the receptacles at all other sites you will be told how many years the other one worked, never with a problem.

I don't worry about it too much though. The only thing I can ever recall seeing actually use the third wire as a neutral on one of these is an electric range. I have never seen an electric range used at a grain storage bin. For the welder outlet scenario I usually make sure I'm not using a metal raceway as sole EGC just in case, but can't recall ever seeing a range in a shop either unless in a separate room with a kitchen type area.

I may be wasting my time all together as this guy seems to be fishing for a "cheap" install. I found what I think is a picture of his welder with the plug attached. From the info on most of the ads for that unit, it doesn't come with a plug. What I see looks more like a L6-30R which makes more sense. He just tried to look at it and found what he thought was it and sent a picture, which was the 10-30R. Does the sizes for conductors/breakers I came up with go along with the unit's nameplate info that I posted earlier? I used Table 630.11(A).

 

[kwired]

I may be wasting my time all together as this guy seems to be fishing for a "cheap" install. I found what I think is a picture of his welder with the plug attached. From the info on most of the ads for that unit, it doesn't come with a plug. What I see looks more like a L6-30R which makes more sense. He just tried to look at it and found what he thought was it and sent a picture, which was the 10-30R. Does the sizes for conductors/breakers I came up with go along with the unit's nameplate info that I posted earlier? I used Table 630.11(A).

I didn't check out your sizing but wanted to say I almost always install 50 amp receptacle and 50 amp conductor for most any welder, unless it actually comes with some other cord cap. You never know what else will get plugged into it someday.

 

[Little Bill]

I didn't check out your sizing but wanted to say I almost always install 50 amp receptacle and 50 amp conductor for most any welder, unless it actually comes with some other cord cap. You never know what else will get plugged into it someday.

I failed to mention but might have been in the nameplate info, this can be 120/240V wired. Since this isn't a normal arc welder, I didn't know if the table would even apply here.

 

[GeorgeB]

I failed to mention but might have been in the nameplate info, this can be 120/240V wired.

Lots of the inverter stuff is that way, but I'm used to seeing different capabilities when powered from 120. Did you catch the 7.1 kW? On 120V? over 50A? ... I doubt it. Is this a name brand unit or one of the orient built attempted copies?

 

[kwired]

I failed to mention but might have been in the nameplate info, this can be 120/240V wired. Since this isn't a normal arc welder, I didn't know if the table would even apply here.

That likely means you can use it on 120 or 240.

You possibly have different output rating for each voltage.

I've seen some that have single phase or 3 phase option also.

 

[Little Bill]

Lots of the inverter stuff is that way, but I'm used to seeing different capabilities when powered from 120. Did you catch the 7.1 kW? On 120V? over 50A? ... I doubt it. Is this a name brand unit or one of the orient built attempted copies?

It is a Simarc, and I have never heard of it. Yes I saw the 7.1KW. That's what I used to get my sizing from the table.

That likely means you can use it on 120 or 240.

You possibly have different output rating for each voltage.

I've seen some that have single phase or 3 phase option also.

I know it can be wired for both, and if I do the job I would wire it 240V.

 

[iwire]

Similar problem we run into on farms around here involves 10-50 receptacles. Virtually few of them actually have any neutral load involved and really should be 6-50 receptacles. Some really old stick welders are still around and they actually have a 10-50 plug on them.

It was common practice many years ago to use 10-50 receptacles to plug in portable augers for loading or unloading grain. Now when they build a new bin whether on site with existing bins or on a new site they want to use the same portable auger at multiple sites. If you put in a 6-50 receptacle you are an idiot for doing so because now the auger will not plug in at all sites where it will be used. If you tell them they need to change the receptacles at all other sites you will be told how many years the other one worked, never with a problem.

I don't worry about it too much though. The only thing I can ever recall seeing actually use the third wire as a neutral on one of these is an electric range. I have never seen an electric range used at a grain storage bin. For the welder outlet scenario I usually make sure I'm not using a metal raceway as sole EGC just in case, but can't recall ever seeing a range in a shop either unless in a separate room with a kitchen type area.

We are at a code forum, I stick with code answers.

I know many range and dryer outlets are misused. I may have a welder that plugs into a dryer outlet myself, along with an SE extension cord for it.:dunce:

But what I do for myself is often different than I would do on the job.

 

[kwired]

We are at a code forum, I stick with code answers.

I know many range and dryer outlets are misused. I may have a welder that plugs into a dryer outlet myself, along with an SE extension cord for it.:dunce:

But what I do for myself is often different than I would do on the job.

Just bringing up an issue I run into frequently and really don't see I can do a whole lot about.

Want to hear something maybe a little worse. If same situation is 240 volt three phase they often use 14-50 receptacles (like a 4 wire range uses). The terminal that is supposed to be the neutral is used for a phase.

Again there is usually nothing else that can plug in there that would use the intended receptacle configuration so there is not many problems. But it could confuse someone trying to connect something new that has no clue that this is somewhat common practice. I'm not trying to say it is right - just stating that it is what it is.

 

[Twoskinsoneman]

We are at a code forum, I stick with code answers.

I know many range and dryer outlets are misused. I may have a welder that plugs into a dryer outlet myself, along with an SE extension cord for it.:dunce:

But what I do for myself is often different than I would do on the job.

oh iwire.... say it aint so..... say it aint so iwire. :happysad:

 

[renosteinke]

"But what I do for myself is often different than I would do on the job." Well! Kudos for honesty!

I recall a collection of pictures, some of the most outrageous electrical violations you could imagine- the work performed by the chief electrical inspector, in his own home.

I also recall a customer whose home had the most amazing stew of lighting and controls, connected with all manner of 'kludge work.' The home's former owner turned out to be the area lighting rep.

Getting back on point .... seldom do I have more stressful conversations with a customer than when a welder is involved. I can't really blame them; the stage is set for a dispute.

The customer has this silly notion that the welder is just like any other appliance, and ought to be able to plug in anywhere. As far as they're concerned, it's just a matter of making the plug fit. Heck, many of these folks don't even use plugs; they attach alligator clips to the leads and clip on to the panel bussbars.

Alas, we know more. Maybe not 'better,' but more. We know that the code assumes a circuit designed for a specific load, and that the usual 'convenience circuit' is an exception to the 'usual' way of doing things. The customers' experience is pretty much limited to convenience circuits, so he doesn't appreciate the difference.

The customers' perspective is also based upon ordinary appliances, where everything plugs in everywhere. Want to dry your hair in the kitchen, or have a toaster in the bathroom? No problem. The plug always fits.

The customer is also accustomed to using extension cords- so becomes confused when he has trouble finding one for his welder.

The fact is, welders do get moved around to different job sites, and there is quite a variety of equipment available. We have the electrical version of the irrestible force(reality) meeting the immovable object (code). As long as those dryer plugs exist, expect them to be used- it's not like the customer is worried about making a few sparks!

 

[kwired]

"But what I do for myself is often different than I would do on the job." Well! Kudos for honesty!

I recall a collection of pictures, some of the most outrageous electrical violations you could imagine- the work performed by the chief electrical inspector, in his own home.

I also recall a customer whose home had the most amazing stew of lighting and controls, connected with all manner of 'kludge work.' The home's former owner turned out to be the area lighting rep.

Getting back on point .... seldom do I have more stressful conversations with a customer than when a welder is involved. I can't really blame them; the stage is set for a dispute.

The customer has this silly notion that the welder is just like any other appliance, and ought to be able to plug in anywhere. As far as they're concerned, it's just a matter of making the plug fit. Heck, many of these folks don't even use plugs; they attach alligator clips to the leads and clip on to the panel bussbars.

Alas, we know more. Maybe not 'better,' but more. We know that the code assumes a circuit designed for a specific load, and that the usual 'convenience circuit' is an exception to the 'usual' way of doing things. The customers' experience is pretty much limited to convenience circuits, so he doesn't appreciate the difference.

The customers' perspective is also based upon ordinary appliances, where everything plugs in everywhere. Want to dry your hair in the kitchen, or have a toaster in the bathroom? No problem. The plug always fits.

The customer is also accustomed to using extension cords- so becomes confused when he has trouble finding one for his welder.

The fact is, welders do get moved around to different job sites, and there is quite a variety of equipment available. We have the electrical version of the irrestible force(reality) meeting the immovable object (code). As long as those dryer plugs exist, expect them to be used- it's not like the customer is worried about making a few sparks!

In other words, to many (non-electricians) there are two kinds of plugs. 110 plugs and 220 plugs. Anything else is foreign but can be made to work by making adapters.

 

[John120/240]

You make it a point to install a dryer recptacle for the hardwood floor guys to

use. Then they will ignore the recptacle & tap on the bus with alligator clips.

Arghh.....