Do I have enough Power in Garage for NEW shop Tools ?

I currently have no Electrical experience and would kinda' like to
know what I have in my garage before I call in an Electrician.
Anyway, I'll soon be purchasing a Thermadyne Plasma Cutter, Miller TIG
welder and Grinders and such (Plasma and MIG are both 240 volt) and
before I buy them, I want to be sure that I can use them !
I currently have a breaker or box of some sort in my garage that is
connected to the main panel (the garage is attached by a concrete
walkway to my basement..)
The panel in the garage seems to be a simple breaker box. However the
cable that goes to it from the main is quite large. I was wondering
if this is perhaps something that can be used for 240v outlets ? If
that makes any sense what so ever...
The cable from the MAIN BREAKER ( described withing as a "2 pole
common 100 AMP Main Breaker" ) goes to the small Garage breaker
(distance of about 20 feet of cable) is printed: "General Cable and
Wiring Company" and is " 8 AWG, Type NMD 7, NYLON, 90 degrees celcius,
300 Volts " (It feels like 4 or 5 wires inside the thick
insulation...)
I have no idea what that means and want to know if this might be
sufficient for my tooling needs.
The Garage currently has 6, 100 watt bulbs in the ceiling (I normally
only use 4 when working) and about 5 - 120v outlets of which only one
is used for my 20 Gal 5hp compressor. There is of course the garage
door opener. The garage is also completely Fire Drywalled from the
concrete base (has concrete foundation) including the ceiling.
Therefore, I will no doubt need to use conduit and would of course
prefer two seperate plugs for the 240v.
Any basic rundown of what I need to get this going would be greatly
appreciated.
Photos or additional information can be supplied !
Thanks,
/Jman...
Reply to
Jman
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8 gauge means that you are probably limited to 50A or so of 220v available to the garage, which is not bad. Check out the breaker capacity of the breaker that feeds your subpanel.
i
Reply to
Ignoramus23363
I ran a whole commercial machine shop with 2 cncs a 5 horse saw, lathe yada yada yada, and had trouble with a 60 amp breaker on 6 ga wire[iirc]
You will be fine. You can put as many breakers as that box will fit, you will not be usuing them all at once, so you will never pop the breaker
Reply to
yourname
Sounds to me like A) a good start, and B) you need professional help. Call an electrician.
Ron Thompson On the Beautiful Florida Space Coast, right beside the Kennedy Space Center, USA
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Reply to
Ron Thompson
What you are describing is a "not too bad" setup for a hobbist, but getting pretty marginal for the size of equipment you are talking about. Several other posters mentioned getting an electrician out to inspect things, definately a good idea.
If I read your post correctly, the main breaker in the basement is only 100 amps. This is a relatively small service entrance to be able to power both the house and the shop at the same time.
The cable to the garage is 8 ga and is likely a full 8-3 with ground. This is good for 40 amps at least. This is enough to power most of your equipment but not all of it at full power.
A Miller TIG welder would likely be the Synchromwave 180 SD. This is a transformer welder, has a high current draw on starting. Very unlikely you would be able to run at full power without tripping the breaker. An inverter welder will take less power, costs 50% more money, probably won't have AC output to weld aluminum.
The plasma cutter will run fine but you will need a compressor for the air supply. Running the plasma cutter when the compressor cuts in is another nice opportunity to pop the breaker.
Net: you can probably get all this to work but you will find it marginal and will need to do some compromises in how you do your work.
Jman wrote:
Reply to
RoyJ
At the moment, if you use the tools one at a time it will work just fine. The problem is with the Plasma, because you also need dry compressed air at the same time. That means running the plasma, compressor and air dryer at the same time.
Figure out what sort of breaker boxes they are - if they are either Federal Pacific Electric "Stablok" or Zinsco "Q" style (also sold as Sylvania for a while), those panels have inherent design problems and are probably due for replacement just on General Principles.
(IE replace the panels at the first signs of trouble _before_ the fire. The fire normally stays inside the steel panel enclosure and burns itself out, but there are always exceptions to the rule...)
You already have a 240V circuit out there for that 5HP compressor - you don't run a 5HP motor off 120V, or they rated it using the infamous "Sears HP" (Stall rating) and it's really 1.5 or 2HP.
If that's 8-AWG Aluminum 90C jacketed service wire it's good for 45 Amps total draw, Copper 55 Amps. (For runs under 50' - not figuring voltage drop.) Since they don't make odd-size breakers, 40 and 50.
With a real 5 HP compressor and a 50A garage sub-feed you MIGHT be able to get the compressor started while plasma cutting, but it'll be very tight. Add in another 25A start current, 8A run current for the refrigerated air dryer you need to get a nice plasma cutter output, and it's close to impossible.
The kicker is that the whole house only has a 100A feed - you need to kick the garage feed up a notch, but you don't have anywhere to get any more power /from/...
Unless you have a little 1-bedroom house with no air conditioning and no electric heat or heavy appliances, it may be Panel Change time. Bump the house main service panel up to a 200A feed, send 100A out to the Garage, and you can go nuts out there.
If it /is/ a very small house, bring another 30A 240V circuit out to the garage for the air compressor, run the Plasma on the 50A Welder receptacle from the existing garage sub-panel. And tell the wife to take it easy on the power use while you're in the shop, or the 100A Main may trip out.
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Reply to
Bruce L. Bergman
That would be useful to clarify. Now Sears goes as far as brazenly declaring their 115V compressors as "6.5 HP".
Bruce, what is the amperage allowed on 6 gauge copper cable (which is what I have supplying my garage)?
Bruce, I run a plasma cutter and a compressor on a 60A breaker. What I do is, when compressor kicks in, I simply stop the cut. I usually cut at about 80 amps output. So far, I have not tripped my 60A breaker. My compressor has a real 5 HP motor and is equipped with an unloader. Once I did not even stop the cut, though I finished it relatively soon after the compressor kicked in.
i
Reply to
Ignoramus23363
Thanks for all the input... Just so you all know, I fully intend to get an electrician to do ALL of the work but I really wanted to know what I was looking at first before I paid to have him / her do the actual work. I should also really explain that the Main Breaker seems to have an "Empty Breaker" slot above the 'current' 100 AMP breaker. I was thinking that perhaps that slot could be used for a dedicated 100 AMP breaker that could be sent out to a new small panel in the garage. If that was possible, I imagine it would certainly solve my current "power issues" would it not ?
Maybe I should take some photos and post them here,...perhaps that might help with identification and such....
/Jman...
Reply to
Jman
The branch circuit stuff around the shop you can do yourself. But when you get inside the Main Panel or have loading concerns, get someone who has seen it before.
They do make All-In-One panels that have dual Main Breakers - but it's a fairly new invention. They have a 200A Main Breaker for the 30 or 40-position distribution panel in that can, and a second 100A or 200A Main Breaker for a remote sub-panel feed. But when you do that, the metering section busses and the service drop conductors have to be sized for a 300A or 400A load.
I've worked on an old commercial building where they had a 100A rated enclosed meter socket (separate can just for the socket) and service wires. First they upgraded the main breaker panel to a 200A Main, then they scabbed on a second 60A enclosed breaker for a remote panel - and they were sucking 150A to 175A continuous through that 100A socket and risers. Got a little warm...
The only thing that saved them was the service risers were Type RHW Rubber, so while the insulation got a bit brittle, it didn't melt.
Would help a whole lot - but Do Not Post Binaries Here, you will make the gods of Usenet angry.
Most ISP accounts include some webspace, put the pictures there and give us a link here pointing at them. Or there's the Dropbox where you can put photos and projects.
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Reply to
Bruce L. Bergman
Great info Thanks,...
Here are some Photos that may help explain what I'm talking about. Perhaps these might help with my description.
Main Panel
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Inside diagram complete
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Inside diagram partial
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300 volt cable I was trying to describe
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Breaker in the Garage...
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Thanks,
/Jman...
Reply to
Jman
#6 THHN (PVC/Nylon) or XHHW (XLPE) Copper 90C - 75 Amps. "Not more than three conductors in a Raceway or Cable or Direct Burial, based on ambient temperature of 30C/86F"
Closest breaker will be a 70, and Home Depot doesn't stock them - Wholesale House time.
You might be able to get away with setting the air compressor to continuous run unloader mode while cutting - the big surge is on the motor start, then it drops way down.
5 HP 240V 1Ph running FLA 1s 28 Amps according to the book, and when the unloader is kicked and the motor is freewheeling it will drop a lot - maybe half. But the start surge could be 125A plus for a second or more, it drops off as the motor comes up to speed.
The breakers have a healthy time delay built in specifically for motor starting - they're sized to protect the wire, and the delay curve should kick when the wire would start getting warm.
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Reply to
Bruce L. Bergman
"Jman" wrote in news: snipped-for-privacy@t69g2000cwt.googlegroups.com:
Based on the very first picture, you will require an upgraded service, from the weatherhead onward. That appears to be the old treated paper jacketing on the wires, not a good thing. The wiring in that house is very old. The service conductors will most likely be 1/0 (maybe that big) feeding your panel, and in no way will carry 200A. I would suggest you upgrade to a 200A service, and sub out the current 100A main panel from it. This would prevent having to rewire everything. I would suggest you plan on upgrading the house wiring in the future to romex, as the type of wiring jacket you have gets brittle with time.
Reply to
Anthony
Are 75 amp breakers available? Any supply houses online that you would recommend (Homeline)?
Thanks Bruce... Any thoughts on finding 75A breakers will be appreciated... That would really help me a great deal.
i
Reply to
Ignoramus16069
I've always understood the code to say that when the ampacity of the conductors doesn't match a standard overcurrent device, a device of the next higher rating may be used. I.e., 80A in this case (assuming Iggy's feed does have 90C insulation.)
This brings to mind the fact that this town is going to vote at our upcoming annual town meeting on the adoption of building codes, which we've never had before. The proposed codes include NFPA 70 by reference. One of the provisions of the article is that the Board of Appeals, which I chair, will hear appeals from the code officer's rulings. At a recent public hearing I questioned the ability of a volunteer citizen board to mediate this sort of technical dispute. So if I'm wrong here, at least I'm right on that .
I'd be interested to hear how appeals are handled in other jurisdictions.
Ned Simmons
Reply to
Ned Simmons
You could use an 80, it will more than likely protect the wire from a total meltdown - But I follow the rule "When in doubt, be a bit conservative" and I either round down, or go bigger on the wire. They allow you to derate the wire on fixed intermittent loads like welders, ovens and AC Condensers, but I try not to push things.
Or you could call the panel makers and see if they have a 75 Amp breaker of that type available on Special Order - they probably don't, and if they do you'll pay a small fortune for it.
I have the NEC 2003 Handbook - the fully annotated "textbook" version with all the why's and wherefore's on how they got to that rule, and how it evolved over time - that particular version is a true eye-opener. Of course it's also north of $100 (eek!) but just reading those descriptive elements in the yellow boxes answers a lot of those questions.
Just adopting the NEC verbatim is a very good start. If you need to make any local exceptions on top of it, that is a lot simpler than trying to write the entire book yourself.
I've never had to appeal a Code Question, I just use this strange thing called Common Sense.
Is it safe? Will it most likely fail in a safe manner? No exposed live parts? Out of reach of small children? Are you grossly violating the rule, or just bending it a little to fit?
(They want 36" of clearance for access, but the building is existing and after you hang the panels you only have 34" available, or you have to move the wall...)
It's safe. Ask me no questions, and I'll tell you no lies.
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Reply to
Bruce L. Bergman
That was more or less the response I got to my concerns - "You'll hardly ever get an appeal." While I don't doubt that's true, my reply was something to the effect that that'll ensure the board will be poorly prepared on those rare occasions we do have to take an appeal.
On the other hand, it's far from certain the ordinace will pass. This town is unique in that, despite having among the highest property valuations in the state, there is no building code and no zoning except that mandated by the state within 250' of the shoreline.
Ned Simmons
Reply to
Ned Simmons
That'll be why the property values are high... No interfering busybodies stopping people from building decent workshops :-)
Mark Rand RTFM
Reply to
Mark Rand
Adopt the NEC (and the family - UBC, UPC, etc.) first, work out the problems second. Those codes have been refined through the years so there won't be too many things that aren't already covered.
And a basic set of codes will keep people from building houses that blow up, burn down or fall over in a summer breeze... Makes insurance companies a lot happier, too.
I would start working on some sort of a zoning system, too - nothing starts the screaming matches like a builder who wants to come into an established neighborhood and triple the density with a tract of 3-story McMansions on tiny lots that are built right up to the lot line on three sides...
Or you get the yutz who builds his house on agricultural land at the end of the runway, or right next to the local Heavy Industry area, and starts screaming about the noise and smoke and vibration, and all the pesticides from the working fields around his house...
And if you codify something simple like "If there are conflicts between codes, or a contractor feels that the code is not applicable in a certain instance, Common Sense and Practical Considerations will be applied to find solutions" you can wing it if and when you need to.
Plus, if your town hires the Building Inspector(s), he can be instructed to avoid letting things get to the formal appeal level in the first place. Find a safe and practical solution in the field, then check back in a few days to make sure it was done.
The problems will often be silly things - like energy management systems where they have a lot of under-loaded track lighting systems and specialty lighting fixtures on one 20A dimmer/relay, and Code insists that each track is 20A and you need to provide a lot more panel ampacity to power them.
(That one has been solved - the building control companies now provide 3A 5A or 10A breakers that can be installed on each channel inside the lighting control panels. Suddenly, those circuits can be figured at the reduced ratings, and now the panel is plenty big enough.)
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Reply to
Bruce L. Bergman
While I'd like to think that a lack of busybodies has something to do with property values here, it's more a matter of geography. Harpswell has a population of around 5000, an area of 24 square miles, and a coastline 150 to 200 miles long, depending on who's counting. Look up Harpswell ME in Google maps for a picture of why that's so.
Ned Simmons
Reply to
Ned Simmons
You spend so much time trying to keep warm that you dont have any time to get into anyone elses way of living.
A Maniac freind of mine would say " there are two seasons in Maine, winter and the forth of July"
As a kid, our family went to Maine in the summer. I remember seeing frost one morning.
John
Reply to
John

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