Wiring a welder outlet

[MrMark]

Since the BS was unbearable I had to post one more time...

I just wanted to say that it's a good thing MrMark is on here to tell all us dumb lazy electricians what we're doing wrong...

Seriously, it's amazing I even passed my test. Watch out, me and my bare minimum standards may set your house on fire!!

Electricians are a sensitive lot. They don't learn well. Well, most people don't learn well either. Tradesman always tend to think they know everything even though their education is extremely limited compared to other avocations. And I don't mean book learning, I mean learning from others and study of publications, where most real learning comes from. Electrician might learn from one guy (his boss) or maybe take a Union class taught by the guy from Mass, so he knows exactly what . . . his boss knows!

Yeah, Aceman, that test is probably a real killer. I'll bet that one really separates the men from the boys.

Like I said Aceman, you may be top notch. I know you are full of yourself. I love the electrical profession. Just pointing out that the electricians I have seen do not do good work. Here's the great thing about it -- no one knows! Where else can a guy with less than 500 worth of hand tools and little training make a better salary than most other tradesman? Most electricians don't even have a copy of the NEC let alone a 2008 copy. They can't justify the cost! I've seen electricians that didn't even have a functioning drill. To them a set of crappy Klein screwdrivers is the epitome of tools.

Compared to a mechanic, whose job requires many times more skill, knowledge and training for way less pay and damage to his body (at least a diagnostic tech) not to mention a ten times greater investment in tools and equipment, electricians have it amazingly good.


I've got to go finish wiring up my welder circuit. Aceman, can you help me?

 

[GeorgiaHybrid]

MrMark,

You might want to look a little closer at that copy you have of the NEC. I admit that I'm an idiot when it comes to knowing all of the code but Aceman, Charles and several others on here have forgotten more than I will ever know.

I am pretty sure that on a dedicated circuit, 8 gauge wire can be used with a 50 amp breaker for certain motor loads (air compressors...) and for welder circuits. I might be wrong but then again, I'm pretty certain you are....

 

[MrMark]

MrMark,

You might want to look a little closer at that copy you have of the NEC. I admit that I'm an idiot when it comes to knowing all of the code but Aceman, Charles and several others on here have forgotten more than I will ever know.

I am pretty sure that on a dedicated circuit, 8 gauge wire can be used with a 50 amp breaker for certain motor loads (air compressors...) and for welder circuits. I might be wrong but then again, I'm pretty certain you are....

We have already gone thru this. It can be used for the welder circuit under the special rules. I have admitted that, but disagreed with doing it. This is 8 romex, not individual wires in conduit that we are talking about. If someone wants to cite to a section of the code where 8 romex can be protected with a 50 amp breaker for a compressor load, I am willing to learn.

 

[MrMark]

Aceman, answer me this if you would:

Do you have a copy of the 2008 NEC?

 

[walrus]

Shared neutrals can be a good thing.

I share neutrals every chance I get, did in my home, did in my shop, do it for my customers.

 

[walrus]

Aceman, answer me this if you would:

Do you have a copy of the 2008 NEC?

Maybe he isn't on 2008 code, some places are still on 99 code. So what difference does it make if he has an 08 code book?

 

[MrMark]

Maybe he isn't on 2008 code, some places are still on 99 code. So what difference does it make if he has an 08 code book?

What would you think of a lawyer you went to see that only had outdated books? You'd walk right out.

Is $100 too much for the "bible" of your profession and your livelihood? You only need one book and you can't buy it?

Oregon is on 2008 NEC.

 

[MrMark]

I share neutrals every chance I get, did in my home, did in my shop, do it for my customers.

I don't doubt that for one second.

Why?

 

[walrus]

What would you think of a lawyer you went to see that only had outdated books? You'd walk right out.

Is $100 too much for the "bible" of your profession and your livelihood? You only need one book and you can't buy it?

Oregon is on 2008 NEC.

So is Maine, other places aren't.

 

[walrus]

I don't doubt that for one second.

Why?

Because it saves money and it takes current carrying conductors out of a pipe.

 

[MrMark]

Because it saves money and it takes current carrying conductors out of a pipe.

How much does it save in money on a typical house?

What is the downside?

 

[JBurgess]

We have already gone thru this. It can be used for the welder circuit under the special rules. I have admitted that, but disagreed with doing it. This is 8 romex, not individual wires in conduit that we are talking about. If someone wants to cite to a section of the code where 8 romex can be protected with a 50 amp breaker for a compressor load, I am willing to learn.

5 HP motor 230 volt 28 amps Table (430.248)

28 amps x 125% = 35 amp min conductors (430.22)

28 amps x 250% = 70 amp max breaker (Table 430.52)

 

[walrus]

How much does it save in money on a typical house?

What is the downside?

Their is no downside and I don't know about houses, I don't do residential work other than my own

 

[sberry]

Also reduces V drop in some cases.

 

[JBurgess]

Their is no downside and I don't know about houses, I don't do residential work other than my own

With the new requirements for arc fault I don't see nearly as many MWBC anymore.

A disadvantage is if a homeowner rearanges the breakers and puts both hots on the same phase overloading the neutral. With the new requirement for a 2 pole breaker this is not a concern on new construction.

This raises a new disavantage that if one circuit trips, to other does too.

 

[MrMark]

5 HP motor 230 volt 28 amps Table (430.248)

28 amps x 125% = 35 amp min conductors (430.22)

28 amps x 250% = 70 amp max breaker (Table 430.52)

Got it. Thank you. I see the motor protective overload device is considered adequate to protect the wire here. The circuit breaker protects against shorts and may be sized up to 250 percent for the reverse time breakers to avoid nuisance trips on the motor's inrush current.

See, that is called LEARNING.

I do note that the 7.5 hp motor is rated for 40 amps draw at 230. 125 percent of 40 is 50 amps. Thus, the 7.5 motor would require 8 in individual wires in conduit or 6 romex. 8 romex would not be adequate here.

 

[MrMark]

With the new requirements for arc fault I don't see nearly as many MWBC anymore.

A disadvantage is if a homeowner rearanges the breakers and puts both hots on the same phase overloading the neutral. With the new requirement for a 2 pole breaker this is not a concern on new construction.

This raises a new disavantage that if one circuit trips, to other does too.

Shared neutrals are horribly dangerous in residential wiring for the reasons you state. The double pole breaker takes two slots, or 4 circuits with tandems and many do not have real estate for this. Many do not have double pole breakers. The other problem with shared neutrals is the potential to destroy circuitry plugged in to outlets with 240 volts should the shared neutral be disrupted. The biggest dangers associated with shared neutrals are to those that come along later to work on potentially non-identified and/or miswired multiwire circuits. All this makes me wonder why anyone would even consider using them to save a white wire. The NEC acknowledges that they can be dangerous.

I agree that done properly, shared neutrals are safe. The problem is that they are rarely done properly and there is great danger that the breaker layout will be changed in the future by unknowing persons.

I had a licensed electrician use a shared neutral with 3 circuits and more! Some were all on one phase. He had many circuits with no grounds. He also cut off gound wires on light cans and tied grounds to neutrals in branch circuit wiring. Everything he did was wrong and dangerous. He passed the test too.

 

[klaw]

why would you even debate wire size for a 10' run cost diiferential is low put in pipe and pull correct gauge

 

[JBurgess]

I do note that the 7.5 hp motor is rated for 40 amps draw at 230. 125 percent of 40 is 50 amps. Thus, the 7.5 motor would require 8 in individual wires in conduit or 6 romex. 8 romex would not be adequate here.

Ouside the NEC I would check with the utility before installing a 7-1/2 HP single phase motor. Some tarriffs limit motor size for single phase reidential. Mine used to be 5 HP.

Rambling a little bit also prohibited across the line starting of over 25HP 3 phase.

 

[MrMark]

Ouside the NEC I would check with the utility before installing a 7-1/2 HP single phase motor. Some tarriffs limit motor size for single phase reidential. Mine used to be 5 HP.

Rambling a little bit also prohibited across the line starting of over 25HP 3 phase.

Do I need magnetic start for this size motor, 5 hp?

I am looking at a 5 hp unit.

 

[JBurgess]

Many compressors come with pressure switches rated for 5 Hp, my quincy was one. When it burned up I installed a magnetic starter. The mag starter also provides overload protection instead of thermal protection.

 

[walrus]

I agree that done properly, shared neutrals are safe. The problem is that they are rarely done properly and there is great danger that the breaker layout will be changed in the future by unknowing persons..

If they are safe whats the big deal?, if you can't figure out how something is wired , keep your hands out of the box. What MWBC circuits do you see that aren't "proper"

 

[oleguy]

If they are safe whats the big deal?, if you can't figure out how something is wired , keep your hands out of the box. What MWBC circuits do you see that aren't "proper"

I see a lot of errors.the main one is the neutrals aren't made properly.code say;s grounded conductor shall so made as not to open with the removel of any device or recpticle.and you would be suprised how many use a tandem breaker (same pole).

 

[JBurgess]

Since this thread is way off topic

These zinco tandems use different poles:

They also are are "back stab" only- no srews

 

[oleguy]

i hate those zinsco's.they are expensive.most tandems used today are single pole.except GE.grouse hinds makes ones with the hook tabs and they are as bad as zinscos.the only reason I like zinsco's is they most all have solid aluminum busses and i make good money changeing them to plated copper.haven't used zinsco's with push in terminals.

 

[MrMark]

Got it. Thank you. I see the motor protective overload device is considered adequate to protect the wire here. The circuit breaker protects against shorts and may be sized up to 250 percent for the reverse time breakers to avoid nuisance trips on the motor's inrush current.

See, that is called LEARNING.

I do note that the 7.5 hp motor is rated for 40 amps draw at 230. 125 percent of 40 is 50 amps. Thus, the 7.5 motor would require 8 in individual wires in conduit or 6 romex. 8 romex would not be adequate here.

Jburgess,

I am thinking of running another dedicated line expressly for a 5 Hp compressor. Based on this discussion and your help, I am planning on running 8/2 romex for this one. It will be about 40 feet of wire and I will use the usual 5S box. I will start out with a 40 amp double pole breaker, keeping in mind I can safely bump it up to as much as 70 for a 5 hp compressor should I have a problem with nuisance tripping. (I also note that if the compresser I end up with is less than 5 hp, I would have to redo the above calculations and not be able to go up to 70 on the breaker under these special rules). If I go over 40 I will make a warning label for the circuit noting that it is breakered for a dedicated motor only etc.

A couple of questions:

One simple one: what hole size to drill for the 8 romex? I was thinking 7/8? Maybe 1"?

I am looking at the Quincy. Does your 5 hp unit trip a 40 amp breaker (assuming you are set up that way and know)?

Which receptical would you pair with this set up? A 40 amp 240 V is what I was thinking. What plug does the 5 hp motor compressor unit usually come with?

 

[hidollartoys]

Yes, I know that, although I can't vouch for your comment re the 7.5 hp motor as I tend to doubt that since the guy says he has romex 8 which can only be protected with a 40 amp breaker for a regular circuit. A 5 hp motor would draw 30 amps at load. Number 8 romex with a 40 amp breaker would suffice for a 32 amp continuous load (.8 X 40) so the 5 amp hotor would be fine on this circuit, but barely. Therefore, I doubt you are correct as to the 7.5 hp motor.

This paragraph is a perfect indication that you know very little about the code and the premise for which the code exists. You also have very little knowledge as to WHY the code allows and specifies sizing and derating in certain applications. You can argue all you wish but you should at least explain the engineering fundamentals that you subscribe to when drawing your conclusions. Without defining the technical or engineering fundamentals, all of your recommendations are, in fact, opinions.

 

[MrMark]

This paragraph is a perfect indication that you know very little about the code and the premise for which the code exists. You also have very little knowledge as to WHY the code allows and specifies sizing and derating in certain applications. You can argue all you wish but you should at least explain the engineering fundamentals that you subscribe to when drawing your conclusions. Without defining the technical or engineering fundamentals, all of your recommendations are, in fact, opinions.

Read further.

What in that quote is incorrect? What that the 5 hp motor draws 28 amps instead of 30? YOU CAN'T use 8 romex on a 7.5 motor because it requires 50 amp wire, so the original poster was, in fact, wrong.


Of course my recommendations are opinions, everyone's recommendations are opinions. What is it about simpletons thinking everything is fact? Almost nothing is fact in this world.

Aren't you the same guy that didn't know that the 75 degree C column of the ampacity table could be used just recently?

I would think you would be more humble and perhaps have scooted away with your tail between your legs, just a little.

 

[hidollartoys]

The reason that the quote is incorrect is the fact that you did not take Table 430.52 (2005 code)into account. This table exists because the code does not want nusiance trips due to high start currents. This is one of these issues that requires a reasonable understanding of the code, motor theory and how these two issues are related, NOT OPINION.

 

[MrMark]

The reason that the quote is incorrect is the fact that you did not take Table 430.52 (2005 code)into account. This table exists because the code does not want nusiance trips due to high start currents. This is one of these issues that requires a reasonable understanding of the code, motor theory and how these two issues are related, NOT OPINION.

2005 code is out. Get a new book. A guy in the business with hidollartoys can certainly afford 125 for the proper book, especially when this is how he makes his living? Am I incorrect on this?

Read further. That was discussed later.

There is nothing in that post that is incorrect except the original poster's statement that 7.5 could be wired with 8 romex. Read it carefully. You will see that post is consistent with Table 430.52 or whatever your outdated code has in it.

 

[Teken]

Let's get ready to Rrrrrrrrrrrrrrrumble . . .

On a more serious note, I appreciate everything I have read, learned from all of you.

In my humble IMO, I believe you should always plan ahead and future proof your designs. This allows you more flexability in the future projects, should money be a key factor then of course you will have it so wired to reflect what is required.

Just my $0.00000000000000000000000000001 on this hot topic

Regards

EVIL Teken . . .

 

[sberry]

Most conscientious DIY types are cautious. Number one thing I see isn't undersized wire but grounding problems. Missing bond screws when needed, both N and G landing on N bar in subs without separate bar and no bond with this leaving ungrounded can , N and G with both wires under same screw.
Handyman types are the worst. I ran across one clipped ground wire out of every install he ever did, ungrounded electric water heaters. Military has had 6 electrocutions from showers in Iraq I hear.

 

[MrMark]

Most conscientious DIY types are cautious. Number one thing I see isn't undersized wire but grounding problems. Missing bond screws when needed, both N and G landing on N bar in subs without separate bar and no bond with this leaving ungrounded can , N and G with both wires under same screw.
Handyman types are the worst. I ran across one clipped ground wire out of every install he ever did, ungrounded electric water heaters. Military has had 6 electrocutions from showers in Iraq I hear.

I recently went thru every plug and light in my house. All done by licensed electricians. Only found one with proper grounding of both box and receptical AND that one which I was amazed to see because it was good, had slit insulation in a really bad spot because the guy slit the romex jacket with a utility knife in careless fashion.

Here is what I have seen in my house alone:

grounds cut off
no grounds at all on some circuits
three and more circuits sharing one neutral
knicked wire inside flex conduit
no ground wire when running flex conduit even though the inspector flagged that one but the guy continued doing it where it couldn't be seen
5 buried j boxes
1 open splice
joist almost sawed in half with a flexibit
grounds nutted to neutral
shared neutrals on the same phase
20 amp breaker on circuits with 14/2 somewhere in the mix
conduits jammed with wires
a 4S box with over 30 wires in it
No ground at all for the subpanel - just three wires
The neutral return for one circuit on a different circuit
wire nuts so loose they fall off
romex connectors not secured
boxes not secured
boxes with drywall screws driven thru them at an angle from the inside to secure the box
GFI without isolated upstream neutrals
boxes no where near the finish surface because proper sized mud rings were not used
plus all the usual stuff of not tightening receptical screws tight enough, nicking wire when stripping it, not getting the wire looped far enough around the screw and on and on
etc.


This one is the best
Picture a 1/2" emt tube that was cut to provide a path down to a box. Then the guy takes the jacket off of 4 cables, stripping back about 10 feet, cuts off the grounds and then shoves all that thru the emt down to the box. This is done in an inaccessible spot.

 

[sberry]

Another one is installing 4 wire cord on dryers and leaving the bond strap connected or putting both the N and G on the neutral terminal. Using old fuse entrance panels as subs in garages.

 

[JBurgess]

To answer your question on breakers I have 2 Quincy and 1 Speedair compressors all 5HP.
Name plate amps 21 and 23 amps. They run fine on a 30 amp breaker.

Why a 30 amp? I had a bunch of them left over from loaded breaker panels. Never tripped so I never bought the 40 amp ones.

I could be wrong, but best as I remember you have to size the wiring based on the NEC chart and not the nameplate amps.

 

[MrMark]

Another one is installing 4 wire cord on dryers and leaving the bond strap connected or putting both the N and G on the neutral terminal. Using old fuse entrance panels as subs in garages.

can you say more about this? I have never seen an electric dryer but I am very interested in wiring 240 volt circuits at this time.

 

[MrMark]

To answer your question on breakers I have 2 Quincy and 1 Speedair compressors all 5HP.
Name plate amps 21 and 23 amps. They run fine on a 30 amp breaker.

Why a 30 amp? I had a bunch of them left over from loaded breaker panels. Never tripped so I never bought the 40 amp ones.

I could be wrong, but best as I remember you have to size the wiring based on the NEC chart and not the nameplate amps.

Cool. Thank you. 40 amp it is then.

Oh, and the receptical? That was my biggest question?

 

[sberry]

A 4 wire fed dryer has insulated neutral. Old 3 wires were bonded, N to the frame to allow for short circuit protection, usually a strap or jumper wire which must be removed for 4 wire. They still allow for 3 wire if it is existing, once its moved or new construction the wire must be changed to 4. Ranges the same way. I believe this was in 96 code???

 

[sberry]

I am guilty of a few things, mostly cause I started half azzed so long ago. Have cords using 3 wire dryer/range hardware but I run a jumper to the metal in a box with cord, with EMT I dont bother.

 

[JBurgess]

Cool. Thank you. 40 amp it is then.

Oh, and the receptical? That was my biggest question?

Table 210.21(B)(3) is your friend.