Miller 211 wiring clarification

[BD1]

Do you have empty breaker spaces for additional outlets at main panel ??
Maybe consider running the larger wire and add subpanel. Then add outlet box off sub panel for welder and run whatever you want from sub panel for outlets.
You only want to do this once.
You may consider installing double outlets .


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[disisme]

Do you have empty breaker spaces for additional outlets at main panel ??
Maybe consider running the larger wire and add subpanel. Then add outlet box off sub panel for welder and run whatever you want from sub panel for outlets.
You only want to do this once.
You may consider installing double outlets .


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Sorry BD1 I’m a bit confused on what you’re suggesting. I have the 200 amp main panel in house and a 100 amp sub panel in the shop is running off the 60 breaker from main panel in house.

[BD1]

Sorry BD1 I’m a bit confused on what you’re suggesting. I have the 200 amp main panel in house and a 100 amp sub panel in the shop is running off the 60 breaker from main panel in house.

Sorry, I saw the photos of the main panel and didn't see open breakers . I missed the sub panel in shop.
I do have a excuse, it's the meds. I had full knee replacement 3 weeks ago.


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[disisme]

Sorry, I saw the photos of the main panel and didn't see open breakers . I missed the sub panel in shop.
I do have a excuse, it's the meds. I had full knee replacement 3 weeks ago.


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Haha sounds like a seniors moment, I get em all the time.

[BD1]

Haha sounds like a seniors moment, I get em all the time.

No, more like this Oxycodone stuff


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[Johnmm]

I just found it a bear to get tucked into the receptacle box, I got it all wrapped up junction box helped but again a bear to
twist 3 10 gauge wire ends together to pit marretts on, but I think easier than the small box.

I don’t think I’ve used a wire Nut since I found those Wago push in connectors. Check Amazon or local electric supply house.

[Sberry]

So what if a guy has to do something again? There is a lot of fear about this too, so,, you got to add another wire or circuit or do it twice to fix it or get it right. Can future proof, all assumption and spectlation, may never happen no matter how much you toss at it. Stuff changes, never even occurred we would have wireless or Internet when I start. Design changes, equipment improves or becomes obsolete. Do some general right, make it easy to modify, face some of it if it ever comes.
We are not talking to a career welder here but a hobby guy buys a 211, wire to make it work.

[disisme]

Thanks for the help guys, Sberry very good point.

[danielplace]

8 gauge THHN and THWN are rated for 50 amps

https://www.cityelectricsupply.com/d...ty%20Chart.pdf


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You can't use the THHN table. Only the 60° because once you terminate it the lugs aren't rated 90° so it de-rates everything. That was the topic of my post actually. The 90° chart is only usable when taking other derations you can start from the 90° charts numbers the de-rate.

[Willie B]

You can't use the THHN table. Only the 60° because once you terminate it the lugs aren't rated 90° so it de-rates everything. That was the topic of my post actually. The 90° chart is only usable when taking other derations you can start from the 90° charts numbers the de-rate.

Ayup.

[danielplace]

When I did my wiring, the county inspector said # 8 THW is fine for 50 amp breaker .
That was good enough for me.

We used to wire 50 amp ranges with #8 for years and one day all that changed and they came up with the terminations needing 90° also and overnight #6 was the new requirement.

It was in South Florida so they tend to be more strict about making change when someone comes up with a fresh idea about something new to start enforcing.

On a welder with a duty cycle #8 is plenty good. If the system was subjected to some continuous actual 50 amp load then #6 may be better choice.

[Willie B]

We used to wire 50 amp ranges with #8 for years and one day all that changed and they came up with the terminations needing 90° also and overnight #6 was the new requirement.

It was in South Florida so they tend to be more strict about making change when someone comes up with a fresh idea about something new to start enforcing.

On a welder with a duty cycle #8 is plenty good. If the system was subjected to some continuous actual 50 amp load then #6 may be better choice.

The terminal temp restriction is older than me, (And I'm very old). The change to 90 degree insulation came C 1985. Then we started having to ignore the insulation temperature, in favor often of terminal temp rating. I rarely see 60 D rated terminals these days though.

[GiantTechGuy]

The manuals are for those familiar with code and NEMA. This machine can be used on circuits to 50A provided the wire is 12 or better. It can use 14 wire,,,, if a 30 breaker is used. the 12 wire and a 30 breaker is good. Better wire doesn't hurt anything but,, the old 211 drew more than the new ones. It drew about 25A and also allowed 14. I used to use 1o for them, recently did one with MC 12 for someone for one. Used a 30 as he doesn't intend to use larger machines. The benefit of 10 is the breaker could be changed to 50.

No you can not use a 50 amp breaker on 10 ga wire.The breaker is to protect the circuit conductors not the machine.

[Willie B]

No you can not use a 50 amp breaker on 10 ga wire.The breaker is to protect the circuit conductors not the machine.

When we size a conductor we consider two factors: Will it get hot? and Will it lose too much voltage. Plenty of people have pointed out that many inverters adapt to any voltage. For them we don't need to get alarmed about voltage if it falls within the range the welder needs. Inverters will use more current if voltage is low.
NFPA 70 National Electrical code addresses this in Table 630.11(A).


A cheap welder has a low duty cycle, some are low as 20% (2 minutes out of 10) NEC recognizes this and allows you to factor I1Max current to less for conductor sizing for specific welders.

This becomes risky where people have the "If it fits it ships" mentality. A 60 year old buzz box might have a 50 amp I1Max rating, at 20% duty cycle or 22.5 amps. the rules allow #12 conductors when limited to the 75 degree column in Table 310.16. When the magic smoke that enables these old relics to work escapes, Bubba is gonna plug in what he finds on Craigslist. I've plugged 7 different welders into the same outlet. No, I did NOT run #14 wire!

[Sberry]

No you can not use a 50 amp breaker on 10 ga wire.The breaker is to protect the circuit conductors not the machine.

You absolutely can. These were installed by the hundreds of thousands code compliant by masters for decades. The breaker does not protect the conductors in this type of dedicated circuit,, in fact not on most dedicated equipment circuits. The welder is the exception for recept/wire matched circuits. Hard wire very rarely for thermal. Applied load is what is thermal limits the circuit in this case.
Breakers do thermal for general circuits with multiple recepts, general use circuits.
Buzz box comes with a 12 cord, it won't overheat a 10 wire connected to it. Single voltage 200 mig comes 12 cord for allowance to connect to 50 welder circuits, new dvi machines have 14 cord, special adapter for 50A. But they won't overheat a 14 wire connected to them which meets the demands of the machine.

[Sberry]

When we size a conductor we consider two factors: Will it get hot? and Will it lose too much voltage. Plenty of people have pointed out that many inverters adapt to any voltage. For them we don't need to get alarmed about voltage if it falls within the range the welder needs. Inverters will use more current if voltage is low.
NFPA 70 National Electrical code addresses this in Table 630.11(A).


A cheap welder has a low duty cycle, some are low as 20% (2 minutes out of 10) NEC recognizes this and allows you to factor I1Max current to less for conductor sizing for specific welders.

This becomes risky where people have the "If it fits it ships" mentality. A 60 year old buzz box might have a 50 amp I1Max rating, at 20% duty cycle or 22.5 amps. the rules allow #12 conductors when limited to the 75 degree column in Table 310.16. When the magic smoke that enables these old relics to work escapes, Bubba is gonna plug in what he finds on Craigslist. I've plugged 7 different welders into the same outlet. No, I did NOT run #14 wire!

You shouldn't have a 14 wire where it s used for different machines. It is allowed [ hence the stuff written in the manual and the code] for specific machines and,,,, it must be limited to 30A breaker when this is done. Now,, this is not 14 on a 50 and if Bubba plugs a buzzer that specs a 50 in to it will send the breaker to a trip before it overheats the wire, prolly not make it thru a rod.
I know it's hard to believe but the code gurus have thought this thru, if it was a problem they would have changed it several code cycles ago, been this way for decades. Just like it's legal to use a 16 cord on a 20A circuit.

[Sberry]

You would think if it was a problem the mfg s like Lincoln and Miller would pencil it in their book if it caused warranty failures, code would have changed if it caused fires or damaged equipment. Instead they invent an adapter and reduce the cord to 14. The make it smaller, made it lighter along with less demand on a whole new class of machine,, but maybe all these engineers are stupid and don't know what they are doing when they spec this.?
The problem couldn't possibly be rather limited understanding here could it? No.. not possible. Couldn't be under what circumstances it's allowed or disallowed? Would be so much easier to read and understand PART of the code and manual. This might be part of the reason the manual is writhen the way it is and intended for those understand it, they suggest a qualified electrician,,, the manual does kind of assume the "qualified" understand this.
Here is where it could be improved to some extent,, maybe. Due to the proliferation of diy install there might be a layman suggestion which meets or exceeds the minimum. There is probably a reason by minds greater than my own as to why they don't do this. There must be a reason they didn't keep the 12 cord and come up with an adapter. Seems 5 ft of 12 cord would have been cheaper than that but I think they may have simply moved some of the internal out to the end. It doesn't need it on 120v which is current limited by the breaker.
I am not totally sure why they do bUT it's probably someting that has never even occurred to me.

[Sberry]

Most engineering is over my head. The skill set of a wireman is different, not to invent the rules but to follow the instructions and install it in a safe manner compliant with the code. You can exceed it, nothing wrong with it except for economy and it may even work a little better,,,, if it would work a lot better then they would spec a better wire, no skin off their *** but they do it this way for some reason.

[Willie B]

You shouldn't have a 14 wire where it s used for different machines. It is allowed [ hence the stuff written in the manual and the code] for specific machines and,,,, it must be limited to 30A breaker when this is done. Now,, this is not 14 on a 50 and if Bubba plugs a buzzer that specs a 50 in to it will send the breaker to a trip before it overheats the wire, prolly not make it thru a rod.
I know it's hard to believe but the code gurus have thought this thru, if it was a problem they would have changed it several code cycles ago, been this way for decades. Just like it's legal to use a 16 cord on a 20A circuit.

Read code. You devalue the amp load of the welder. But if tripping is a problem, you upsize the breaker to as much as 200% of the I1Max of the welder. You might find yourself with a #12, and a 100 amp breaker. Any way I look at that it seems wrong. What gets protected by this combination? I'll disagree with code on this one.

[Sberry]

That is being read wrong. It's not allowing the 12 on a 100A breaker. It's limited to 50. I have it explained to me by the guru but I forget all the details and probably don't understand it well enough to slain it anyway.
I have never found anything I know enough about it to disagree with the code on. I found some stuff at first I thought there was a fault with but upon further investigation I find its my understanding that is the problem, often incomplete. I am not really a natural electrician or mechanic for that matter, only come to it by sheer repetition and questioning specifics.
Lots of code and the calculations are over my head, only know some of this in given area I work with, wiring welding machines and comps and some general circuits.

[Willie B]

630 addresses welders. 630.11(A) gives factors for choosing conductors. It allows as low as .45.
630.12(A) and (B) limits the 200% overcurrent based on I1Max of the welder to 200% of the conductor rating.

[Sberry]

The instruction manual tends to simplify it. Says min wire size max breaker. It's not complete in the eplanation that once the wire is above the minimum a breaker up to 50 may be used. 50A plug the unit comes with is limited to 50 ocpd.

[Sberry]

Right 200% of the conductor rating of the 12 thhn to be 50A. 100% would be 25A, 200 50.

[NHWelder]

Hi, Thanks for all the great info! I'm a newbie who just bought a new Millermatic 211. From reading what you all posted it seems as if a bigger wire won't hurt anything as long as you use a breaker sized to protect the machine that you're going to be using.

I plan on running a dedicated 220v circuit for the 211 using 6-3 wire with a 30 amp breaker. 6-3 because I have happen to have a 50' roll of it already. A 30 Amp breaker because it seems that 's what the 211 needs for protection.

Is the wire too big?
Should I use a larger breaker?

Thank you Gentlemen.

[Broccoli1]

Hi, Thanks for all the great info! I'm a newbie who just bought a new Millermatic 211. From reading what you all posted it seems as if a bigger wire won't hurt anything as long as you use a breaker sized to protect the machine that you're going to be using.

I plan on running a dedicated 220v circuit for the 211 using 6-3 wire with a 30 amp breaker. 6-3 because I have happen to have a 50' roll of it already. A 30 Amp breaker because it seems that 's what the 211 needs for protection.

Is the wire too big?
Should I use a larger breaker?

Thank you Gentlemen.

Wire will be fine.

as far as the CB- as Sberry mentioned- the manual calls for a 25amp BECAUSE it also states the minimum wire allowed BUT if you go up in wire size you can use a bigger CB.

You could stick a 50amp CB in there using 6/3 wire and be good.