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Henrik
| | Posted on Tuesday, November 21, 2006 - 01:25 pm: | 
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I live in a semi-attached row house (if that's the proper description?), so I'm thinking me cranking up the drill hammer with a 1" drill through the wall to my neighbor might tip someone off, middle of night or not 
Question though: what gauge wire would I need run to the garage to safely feed a 240V welder? The garage is currently fed through a 3-wire cable off of a 2x40A breaker. Is that enough info to take a guess at the wire gauge?
Henrik |
Jackbequick
| | Posted on Tuesday, November 21, 2006 - 03:22 pm: |
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The amperage requirements will vary with the capacity of the welder you buy. If you think you know what you want to buy, look up the maximum current draw in the specs.
As example, an older (transformer type) Miller Thunderbolt AC/DC I have is rated as drawing 67A from a 230V circuit at its maximum welding current (300A).
The newer inverter type welders draw less current than the transformer type.
I would install that using 8/3 w/ground. That is a sheathed cable for air mounting (not in a conduit). It has four 8 gage conductors, two hots (black and red), a neutral (white), and a ground (green).
Ten or 15 years ago household 240V runs had two hot conductors and a neutral, there was not a ground. That kind of wiring can still be found in many homes today, you can spot it by outlets that only have three sockets for the plug. By today's code you'll want to use the 8/3 w/ground wire. That has the two hots, a neutral, and a ground (green) and the outlet has a fourth opening.
As I mentioned earlier, I used the above welder on a 30A clothes dryer outlet at lower amperages (around 100A or less by the power control on the welder).
I always recommend spending the extra money to get an AC/DC welder instead of one that has AC only. You'll never regret it if you do very much welding and I think 90 percent of the time I used mine on DC instead of AC.
Jack |
Csg_inc
| | Posted on Wednesday, November 22, 2006 - 09:11 am: |
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That quick Jack is quick...The only other info needed is how far are you going? You can get some voltage drop if the distance is too great. You could always size the wire up one size (lower number) if you are concerned. The other thing is the duty cycle of the welder will also help you to not fry the wireing. |
Jackbequick
| | Posted on Wednesday, November 22, 2006 - 10:18 am: |
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David's right about the voltage drop of course. Voltage drop is of much less concern on AC circuits than it is on DC circuits but there will be some. You can calculate the voltage drop from this link here:
http://www.powerstream.com/Wire_Size.htm
As an example, the voltage drop on a 75 foot run with the #8 copper wiring mentioned above would be about 6.5 Volts at the 67A max draw.
If I was running some kind of voltage sensitive or voltage critical equipment I might go to a larger conductor to reduce the drop. But for that welder the #8 meets the code, is perfectly safe, and easier to handle and install.
Watch out on the attractive prices on aluminum wiring. Don't lose track of the fact that aluminum wiring wiring presents more fire hazard/safety issues in use and has about double the voltage drop of copper.
Jack |
Henrik
| | Posted on Wednesday, November 22, 2006 - 12:57 pm: |
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The cable run is about 75' from main panel to the sub panel in the garage. I'm hoping that they ran #8 wire, but seeing the work that was done in the rest of the house, they most likely ran #10 ... it is copper though.
Maybe I can talk MikeyP into taking a look if he's joining us for any of the upcoming Xmas shindigging in NYC.
I'll keep you posted.
Thanks for all the advise and useful info.
Henrik |
Jackbequick
| | Posted on Wednesday, November 22, 2006 - 06:34 pm: |
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How big is the sub panel? That would normally have two main breakers (one on each hot leg and both of the same value) that are paired to operate together and those service the entire load on the subpanel. And are also used for turning the subpanel on and off of course.
So what ever value is marked on those two main breakers (50A? 100A? 200A?), that is the maximum load rating of the subpanel.
Then, the subpanel would then have more breakers for each of the various loads (outlets, lights, etc.). Those breakers would typically be 15A for lights, 15A or 20A for outlets, etc.
The paired breakers below the main breakers, if there are any, are for 240V outlets.
So if you have a 100A subpanel and say, for the sake of argument, the load breakers already on it total up to 70A (2 @ 15A, 2 @ 20A), you can still put another 100A outlet on the subpanel. But you have to manage your loads so that you are not exceeding the 100A main breakers or they will trip.
It is not at all uncommon for the value of all the breakers in a panel to exceed the value of the mains. It only becomes an issue when everything is being used to full capacity.
MikeyP can probably glance in your box, maybe remove the front panel to check wire size markings, and quickly tell you what you have and how far you can go with it.
If you can get a 30A or 50A outlet on it, you'll probably find that adequate for anything you'll ever want to do with the modern inverter welders with welding capacities up to 200 or 300 Amps.
Jack |
Bigdog_tim
| | Posted on Wednesday, November 22, 2006 - 08:42 pm: |
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Ok - this thread is very appealing to me. I am a software engineer by profession but am enjoying wrenching as it is a totally different thing. I have often thought about equipping my garage with welding equipment - only because it seems that danger is involved and for whatever reason - that always seems to appeal to me.
That being said - for a total NEWBIE - what sort of training would you recommend before I committed welding equipment to my garage? I would like to fabricate lightweight stuff for the house - non load bearing, sheet metal like things - and stuff for my bikes - from frame changing to bodywork.
Thoughts? Suggestions? |
Reepicheep
| | Posted on Wednesday, November 22, 2006 - 10:33 pm: |
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Bigdog... I am an EE(T) by training, and was a software engineer for a long time, and am now doing application security architecture. The deeper I get into computers, the more I enjoy fixing physical things.
Welding is great fun. Start with a good book, Home Depot stocks one.
For equipment, I ended up getting lucky and scoring a used Oxy Act rig. I think its a great way to start. I got it for under $100... the tanks are not official, but I have been able to find people to fill them if I talk nice enough.
It can braze, cut, weld, and heat for bending. It won't weld as fast as a MIG unit, but it can adapt to weld anthing from sheet metal to 1" plate. It's cheap to run, highly portable, and while slow can make outstanding welds in terms of both strength and beauty.
Harbor frieght has a small setup, not sure if anyone will fill the tanks or not. Here in Cincinnati, I had to call around, but found a couple of place that will fill my third party tanks, and I have heard that tractor supply will fill them as well (no questions asked).
A 5 foot tank setup (not sure what they are called) lasts freaking forever, are sort of portable, and don't need any special wiring.
Or spend the big bucks and get TIG. MIG is fun in that you can know next to nothing and produce really fast really strong welds, but they are covered with turkey poop.  Good for production welds, but kinda uninspiring.
Above all, I would encourage you to do it. Any man (or motivated woman) should know how to fire and clean a gun, ride and maintain a motorcycle, and weld and cut metal. |
Bluzm2
| | Posted on Thursday, November 23, 2006 - 10:20 am: |
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Bill,
I couldn't agree more with you re the computer vs fising "real" things.
There are days when I can't wait to get home to "burn some metal".
I do have to disagree about the quality of MIG welds. If the metal is clean and the rig set right, the welds are very smooth.
They just don't have the neat ripple "stack of coins" lok of a TIG.
Ther are ways to manipulate the TIG gun to make the welds look very nice though..
I love my MIG, but want a TIG!
Brad |
Reepicheep
| | Posted on Thursday, November 23, 2006 - 04:00 pm: |
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I should qualify then and say that when *I* MIG weld it looks ugly
(and my gas welds aint the prettiest either) |
Henrik
| | Posted on Thursday, November 23, 2006 - 05:35 pm: |
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Jack; the garage sub-panel is fed through a linked pair of 40A breakers. I checked the wires in the main breaker panel, and there are unfortunately no markings.
The sub-panel in the garage has 5 20A breakers (I believe 20A is minimum code in NYC).
Jack's table with wire diameters gives me a starting point, so I'll measure and get an actual size ... hang on a sec ... ok, 0.1285" diameter = 8 AWG wiring. Better than I thought
Henrik
(edited for stupidity ...)
(Message edited by Henrik on November 23, 2006) |
Henrik
| | Posted on Thursday, November 23, 2006 - 07:12 pm: |
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Finally got the courage up to check the price on the Esab ... just shy of $2000 - hmmmm.
Henrik |
Jackbequick
| | Posted on Friday, November 24, 2006 - 08:17 am: |
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If you look at the sheath on the cable to the subpanel you should be able to see markings with the size, you might have to look close with a flashlight if they are just embossed in the sheath. They are probably something like AWG 10/3 for a 40 Amp panel. The 10/3 marking does not include the (usually bare) ground lead.
I just looked at the Esab's those look pretty nice. The 160, 161, 252, or 260 all look like they're worth lusting over. 10-15 years ago the Lincoln 175 Econotig (or something like) was the one that drove me crazy for wanting it.
Those 100 series models draw around 27A so they should work fine off of your 40 Amp panel, the 200 series (70A +/-) will too as you're not drawing full current. Are you looking at one of those models?
I took an first year welding course at a junior college and that ran me through the basics of gas, stick, TIG, and MIG welding. You used each process enough to be adept at basic welding and also to understand the differences in the processes. You could look at something that was broken or a project you wanted to build and you just knew that (1) you needed to have and know more than one process, and, (2), which process(s) would work for you.
Jack |
Henrik
| | Posted on Friday, November 24, 2006 - 09:50 pm: |
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Jack; no markings on the wires oddly enough. But the measurement pretty much confirms that it's 8 AWG, and in NYC the armored metal sheath (BX cable) *is* the ground.
Looks like I'm set for power as long as I don't keep anything else power hungry on at the same time.
As for welders, I'm just browsing for now. Economy may well dictate that I start out with something used.
Welding courses are a great idea - I'll look into what is available around here. New courses should be coming up in January.
Henrik |
Bigdog_tim
| | Posted on Wednesday, November 29, 2006 - 09:21 pm: |
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I need some help from the experts. I am going to ask for a welding system for Christmas. Since it will be the ONLY thing on my list - confidence is very high this is what my significant other will get me.
Most likely, she will shop at Harbor Freight.
Background - I have ZERO background as a welder. This will be 100% self taught.
I want to be able to make tools for my bikes (there is ALWAYS a tool that is needed), some frame or other similar structural welds, something decorative (I doubt it - but thought I would throw this in), etc.
My thoughts are to buy the book(s) and a lot of material to figure it all out. I do think I will be welding aluminum, steel etc. I was leaning towards MIG for this reason.
Note: Consider me a TOTAL newbie. Looking for some advice. I don't want to spend more than 500 (have to have special dispensation to spend more than that). I MAY need to get some electrical work done in the garage (only have 110 in there now).
So what does everyone think? Recommendations? |
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