the old 220v wiring question

[dmaclusk]

Simple wiring question (haha!)

Purpose: shift some of my big equipment to 220v (table saw, DC...)

Conceptual plan: Run a 30amp, 220V line in the garage from the panel (45 feet max run length.) I'd like to put in two outlets, one on either side of the garage.

1) is 10/3 the correct gauge?
2) can I junction in the attic and drop a line down either wall (that always seems easier to me than chaining them together).
3) tips?

Once a real shop is built I plan to NOT use the 220v in the garage. Rather, I'll remove the 30 amp breaker and plan to replace with either 60 or 100amp to run to the out building.

Thanks!

[JDsharp]

>Simple wiring question (haha!)
>
>Purpose: shift some of my big equipment to 220v (table saw,
>DC...)
>
>Conceptual plan: Run a 30amp, 220V line in the garage from
>the panel (45 feet max run length.) I'd like to put in two
>outlets, one on either side of the garage.
>
>1) is 10/3 the correct gauge?

Yes, 10awg handles 30A (rule of thumb: increasing 2 std sizes doubles the current carrying capability, ex: 14awg=15A, 12=20A, 10=30A, 8=40A, 6=60A... see how you skip over the next larger size wire doubles Amps, ie, from 14 to 10 goes 15A to 30A??)

>2) can I junction in the attic and drop a line down either
>wall (that always seems easier to me than chaining them
>together).
I wouldn't... see tip (come on by and I'll show you my setup, which is exactly what Sonny et al., had told me to do.... I used a bigger breaker (and 6awg wire), but theory is same

>3) tips?
After installing the duplex breaker in the house panel, I would run a cable (2 hots and 1 bare gnd) from your house panel to the garage and into a sub-panel (which you can use later in another shop). From THERE, you can run wires to either side, AND you'll effectively have 60A's available (2 legs of 30A for 120vac, or 30A for 220vac) you're TS, DC and other stuff will use only a portion of that, so you can have additional 120vac lines as well. The way the breaker boxes work, half the current for a duplex comes from each conductor, so if your DC takes, say 8A, only 4A from either side of the line is used, allowing the other 22A (theoritical, since you don't want to use all of it, all the time) OR have 52A of 120... but remember, you'll NEVER have all your tools on at once

BTW, I'd be glad to help on Sat, if you need.

HTH,
jd

[dmaclusk]

I didn't really want to do the subpanel thing if I could get away with it. The main panel is already in the garage. Kinda thought I'd pretend it's an extra dryer line :)

Though what I really need to do is finish up the "hot" project list and get the darn shop built!

[JDsharp]

well, then, you can just put in the new breaker, and run 2 wires, one to either wall outlet and be done with it...., but I bet a 20A breaker for 220vac would be plenty, since you'll probably only have one tool plus DC running on 220v at a time... then you could use 12awg wire, save a little money.. enough to pay for two outlets and boxes, I bet.

jd

[arcticfox46]

I have a DUMB question?

If the amperage load on -say- a TS, wired for 220v is half that of the same TS wired for 110v why do you need a 30 amp 220v breaker, and why do you need #10 wire?

My TS is 18a @ 110v. I use #12 wire and a 20 amp breaker. Same TS on 220v uses 9a. I could easily wire with #14 and have a 15a breaker.

Only reason I see to run #10 wire with a 30a breaker is if you are going to have 3-4 machines running at the same time and under load. Three machines times 9a each equals 27 amps. If we used that locic, then we would need a 60a 110v breaker and do our 110v shop wiring with something like #6 wire. uuugggghhhh!!!!!

So, why do the 220v wiring with #10 wire and 30a breaker?????

[dmaclusk]

If I run the TS and DC at the same time (which I usually would), the idea was to have a single 220 breaker with two outlets. In that case, I'd have/want to go up to 30 amp. I don't think I want to hit max load.

JD has an interesting idea though. JD's idea, combined with my brothers FIL, who was an general contractor for about 20 years (who, btw, suggess that while it can be legit to run two 220v outlets on a single run, it's generally not done cause some other nut may come overload it later.)

My CURRENT thought is to run a 12/3 on a 20amp breaker, and just do one outlet. This is, in theory, a short term solution. Plus that's easier, I spend less time in the attic, and I can do it in about 30 min (which usually means 6 hours, and 8 trips to Lowes).

I'll give you a buzz if I run into a problem though JD :) Thanks for the reality check all :)

edit: typos galore

[JDsharp]

Leo, not a dumb question, just a normal thought.
>I have a DUMB question?
>
>If the amperage load on -say- a TS, wired for 220v is half
>that of the same TS wired for 110v why do you need a 30 amp
>220v breaker, and why do you need #10 wire?

IF you were to make a run from breaker to 2 outlets, and run each at max capability, then yes, use max wiring... most often, you meet OR exceed the requirement AND use less thatn the max, just for safety's sake

>My TS is 18a @ 110v. I use #12 wire and a 20 amp breaker.
>Same TS on 220v uses 9a. I could easily wire with #14 and
>have a 15a breaker.

True enough.

>
>Only reason I see to run #10 wire with a 30a breaker is if
>you are going to have 3-4 machines running at the same time
>and under load.

True again, tho most of us are loners and would only have 1 large tool and the DC running at same time....

>Three machines times 9a each equals 27
>amps. If we used that locic, then we would need a 60a 110v
>breaker and do our 110v shop wiring with something like #6
>wire. uuugggghhhh!!!!!
>

That was dave's first idea, but not a requirement... when he asked what wire to use for 30A, he had not yet said he might use 220v, or so I recall.... "usually", you have to consider 2 things:1) the breaker in panel or subpanel that carries power TO the shop, 2) the wiring inside the shop.... I suppose I mexed the two together, and wasn't very clear...

In my case, a 6 awg cable from a 60amp duplex in my home feeds a sub-panel... inside the panel, I have 6 single size breakers for 120v and 1 duplex for 220v...so, theoretically, I have access to 120Amps, via 2 60amp lines, fed by breaker from house....THIS is where a bigger breaker gives more overall power (generic term, not wattage reference) to shop... inside shop, wiring need only be big enough to carry current of tools +10% fudge factor or so

>So, why do the 220v wiring with #10 wire and 30a
>breaker?????
>
No need, just fit into the earlier talk, when 10awg=30amp was mentioned; if dave was gonna "mix" 120 and 220 in his wiring from panel, THEN the FEED would be bigger than an individual tool needs


make sense?

jd

[arcticfox46]

JD,

Yeah, I understand. Just tring to make some points clear.

I am running a 60a 220 breaker in my main panel, with a sub panel in my shop. #6 wire from main to sub., I know how that all works. If I turned on everything in my shop, I would pop it fer sure.

Another thought about only running one wire to one recepticle. Somehow there are thoughts that putting two recepticles on one circuit is a lot. Not so.

There is no difference between 110 wiring and 220 wiring. If I run a circuit of 110v I don't think that way. I will generally put maybe 6 or 8 or more recepticles on any given circuit. Chances are that you are not going to overload the circuit. I presently have a 110v 20a circuit in my shop. I have plugged into it, band saw 15a, planer 16a, TS 18a, jointer 18a, RAS 12a, Router table 11a, and several recepticles for and tools. I do NOT pop the breaker, but they are NOT all on at one time. I have had shop vac AND router running on it. I have also had shop vac AND planer running on it. I do however have two seperate circuts in my shop for tools. DC runs on a seperate circuit, but there are several aditional recepticles on that circuit also.

Another point - go into you main panel - add up all the breakers. Does the total load exceed the main breaker. YES most likely it does. Do we EVER pop the main? NO.

So, why then, are we afraid to wire up 4-5 recepticles on a 20 amp 20v circuit with #12 wire. If you do by chance have a DC @ 9 amps AND a TS @ 9 amps running (18Amps) and somehow we who are generally alone in the shop turn on the jointer @ 9 amps (27amps) , it will pop the breaker. No big deal. just turn the stuff off and reset. Not gonna burn the house down, and it will probably not happen.

Just seems to me to dramatically underutilize the breaker and panel. One or two recepticles per breaker. Need a really big load center to accomodate a shop with several pieces of equipment.

[JDsharp]

Leo, sorry if I sounded condescending, I didn't meant to.

I totally agree with your remarks, but I tend to err on the side of over-cautious...

>So, why then, are we afraid to wire up 4-5 recepticles on a 20 amp >20v circuit with #12 wire.

I typically have three outlet boxes/15A circuit breaker and 4 outlet boxes/20A breaker, so we agree here, just slightly diff numbers

>If you do by chance have a DC @ 9 amps AND a TS @ 9 amps running >18Amps) and somehow we who are generally alone in the shop turn on >the jointer @ 9 amps (27amps) , it will pop the breaker.
>No big deal.

Only place I disagree, slightly.... the inrush current on some electrical devices can damage others on the same circuit, if the 2nd/4rd tools aren't properly designed; I saw this in the industry, during some NDT (Non-Destructive Testing) I performed, looking for failure mechanisms in electrical circuits connected to 30A ditribution panels (previous job)..... but generally, you're right, especially if you add one tool at a time and don't power them all up together, when you're sure to pop the breaker.

>Just seems to me to dramatically underutilize the breaker and panel. >One or two recepticles per breaker. Need a really big load center to >accomodate a shop with several pieces of equipment.

Yep, we do under utilize, but not as much as it may sound; my exapmles were probably over-simplified, in case other "newbies, like me" reads it.

Thanks for the cross talk, Leo. hopefully other aren't annoyed by our diatribe. I for one, enjoy this kind of discussion, and often times learn from same.

jd

[arcticfox46]

JD,

You do not sound condescending in any way shape or form. I was thinking you might think I was trying to be a PITA. Not so, just conversing.

The surge in the line affecting other motors is something I did not think of. DC would most likely be running constant. Turning on the TS may cause a momentary voltage drop to the DC motor and thereby cause a momentary 'brown out'. The drop however IS momentary, and I think (but not sure) not really long enough to cause a problem.

Anyway, it has been an enjoyable discussion. JD your comments are good and sound. Makes the brain think. Good to think. Thank you for your comments.

Sorry about hijacking the thread - didn't really mean to. But I do hope the discussion helped the original poster.

[JDsharp]

Leo, thanks for the comments, too. The surge/in-rush thing can also sometimes pop a breaker, too.

As for hijacking, as long as we stay somewhat on topic, I think it's fine... unless we p1ss off Dave :), who started this thing. Anyway, including our several replies, there's been 90+ views, so someone I bet that has learned somthing, if only you and I.

Later,
jd

[dmaclusk]

ROFL. I was enjoying the discussion. Please continue! I'm always willing learn something new :)

And, to give you guys something new to talk about..
what's the Code say about two outlets on a single 220 line? Seems everyone really does just run single outlets!

[Super Ry]

Gotta gree with Dave - good read! I'm always a fan of learnin more lectrical stuffs! :)

[JDsharp]

You won't believe what i found in the archives..... this is Sonny and Tim, back in May of 2001, when they were guests here... just proves Sonny is who he says he is (never backs down) and Tim can hold HIS own, too.... great read.... BTW, it doesn't answer the question about what the Code says..... I had a good ref for the code back in Apr when Sonny sent me on the chase for knowledge, but I can't find it now That dam google just gives me folks with things to sell, and lest I pick up a copy, I can;'t quote it.

BUT, as for me and MY shop, I have two sets of wires from my 220 breaker, one going down onwe wall to the DC and the other across the room for my jointer.... no problems, no hassles and NO popped breaker.... just like Leo said, what's the problem? I do it with 110vac, why not 220vac?

Here's that thread:(number 467-compare that to today's #'s)
http://www.woodworking.com/dcforum/dcboard.pl?az=read_count&om=467&forum=DCForumID9

Sure wish I had time to read all those encounters...Tim, I have a greater than ever respect for your counsel, since I see how long and hard you've been at it. :7

jd

[Super Ry]

MAN - blast form the past - wonder how Lous plane business is sailin??

As to the code issues, I found this forum that had some REAL smart folks on code - some contributed to the NEC??!!?? I needed some quick answers to the sub addition (relative distance to gas supply and distnace run calcs. Amazing the help you can find on this internet thing :)

http://www.selfhelpforums.com/forumdisplay.php?f=4

Goodrich is the king cheif - real smart cool fella.

[JDsharp]

THAT's IT!! That's exactly where he sent me... gonna bookmark that bad boy right now!!


Did you see the calcs? Just be sure and respect the "type" of shop situation you have, such as detached, with or without "non-conducting pipes attached" (plumbing connections between the 2 bldgs... if not, then you DO NOT run a ground wire between the two, you connect your own 8'x 1/2", copper grounding rod.....

FWIW: that site is IT!!

Thanks, Ry. How's Tracey? Been thinkin of you guys lately:)

jd

[KnightJCK]

Oh great! Why'd you have to post that? :-) Now I'm gonna have to split my forum time. I can't keep up here as it is!

Thanks for the link.

Jon
"Don't need a tool twice!"

[arcticfox46]

Well,

I am not an electrician, and have never worked in the feild, however I have a few friends that are electricians. I ask them from time to time when I need help. My friend Paul is a liscensed electrician, but he is not in household wiring and not up on the codes. I asked him about the codes for 220 but he didn't know for sure.

He did mention about thinking about what was going to be on a given circut and wiring accordingly.

My comments were just that comments. Just comments. I wish I was more knowledgable about the codes but I am not. Would be nice if a real electrician were in the group though. I think he would be able to shed some light :) for all of us.

[JDsharp]

yes, you're right leo. Sonny's an 'lectrician, i think. i bet he could put an end to this question.... but Leo, what you said is right in line with the wiring principles, and i'm sure it's safe and permissible to put multiple outlets per breaker:7.

Anyone get that far thru the code yet?

jd

[dmaclusk]

Glad I stumped everyone :)

In an ideal world, I'd like to run one 220 line, plug the DC AND either tablesaw or jointer into it.

Jointer at 220v draws ?? amps (Yorkcraft 8", 1.5HP)
Tablesaw at 220v draws 6.5 amps (Ridgid 3612)

DC at 220v draws 5.5 amps (Jet 1100C)

So my math is:

Total amps with 2 devices on = 6.5 + 5.5 = 12 amps

A 30amp 220v line should be more than sufficent. (given the 80% rule a 20 amp line should be ok, but I don't mind overkill if that does no harm)

Each tool pulls less than half the total amp capacity of the circuit.

Of course, I can always keep the tablesaw and DC on 120v for now, since that's what they are currently wired for. Only the jointer NEEDS 220.

[JDsharp]

I say go for it!! re-wire for 220, put 'em both on there.... I'm runnin DC and jointer simultaneously on a 220v breaker, tho on seperate wires... effect is same, and they're doing great!!

Man dave, I still can't get those speaker stands out of my head.. LOML saw them, paused and I said..."No, I don't think I could do that, at least not yet!!

jd

[Sonny Edmonds]

Good read guys! Needs a bit more salt, in my opinion, but just fine! ;)

30 amps.....
One basic to bear in mind is that the CB is sized to protect the wire it is feeding. So a 30 amp circuit wants 30 amp rated wire, or #10.
You guys touched on the inrush point. And the 15 amp should be sufficient thought.
Let's chew on them in that order. Inrush... when a motor is at rest (dead stop) and you flip the switch to bring it on, a massive amount of amps pours into it because from the utillity end (me) it looks like a big load starting. The voltage dips, the amps charge the windings in the motor and the magnetic energy begins to pull and push the rotor in the motor up to it's syncronisis speed.
That inrush of current can be 5-8 times the normal FLA (full load amps) of the nameplate rating. It normally only lasts for a fraction of a second (we measure it in milliseconds), so your time delayed CB will withstand it for a few seconds.
That massive inrush of current with a 30 amp circuit can allow the motor to come up to a normal operating speed much faster than a smaller 15 amp circuit would, (IF the 15 amp circuit could even withstand the inrush imposed on it without tripping).
The bigger the wire and the CB available to the motor at the moment of starting the better, within reason. The voltage drop is not as severe and the current (amps) can get to the windings easier to bring it up to speed. Where incidentally, it will drop below the FLA of the motor in most of the applications we use.
A compressor is one where the load is on good and hard, and stays that way until the pressure is satisfied. But about everything else is underloaded even in use.
That starting inrush is the reason to try and provide ample wiring for the overall longevity of the motors we use.
What about when we do overload our motors? Well, just about all of them have a thermal trip device buried in the windings or mounted externally that will pop and open up the circuit in the motor and not reset until it cools for a while.

As for running multiple pieces from a single circuit, well, I do that myself with my TS and a 1 1/2 HP booster blower under the center area.
But they don't both start at the same moment. I start my DC system which draws on a 20 amp circuit for the cyclone, and on the 30 amp circuit headed for the TS which has 2 outlets on it. They do start simontaniously by remote control, but are on different circuits.
Then the TS is turned on and off as desired, fed by they same 30 amp 240 volt circuit run from the sub-panel to the center area of the shop.
I do have my TS's recepticle set up so I can plug in the BS or jointer in the future, when I change them over to 240. But so far I have got by without it. (If I could remember to get the damn plugs I'd have done it by now. }> :P )

Likewise, you don't want to over tax a single breaker if you can set it up so you balance the load with alturnate CB feeds. How that works is to have two single pole breakers feeding 240 and a neutral with an equipment ground around your shop.
Say you set your recipticals at 48" elevation, then every other one is on one CB and the alturnate along the wall is on the other CB with the common neutral.
Say you have 6 amps on circuit one running, and you start up 8 amps on circuit 2. Well the two sources, L1 (circuit 1), and L2 (circuit 2) cancle all but the difference in the neutral and only rhe remaining 2 amps flows back to the panel and ultimately to the transformer supplying your house. (You still get billed for the 14 amps you are using by the power company. }> It's just that the power is being used more effectively.)

To make it all a lot easier, just figure on 20 amps for your outlets and lighting. One roll of #12, 250' of NM of MC cable. And enough #10 to take care of your TS and if you want to junction off along the way, go ahead.
Surface mount everything you can so you can remove it and take it with you if you move. Yeah, it won't be neat and pretty, but it will be practical if you ever want to change it or take it with you.
Check your local code requirements. Mine requires MC (metal clad) cableing be used in a garage "in case somebody bumps it with a shovel or leans a rake against it." (Quote from an ex-city electrical inspector. Gee, musta got caught with his hand in the cookie jar.)
I only use those two guages (#12 & #10) in my shop and it covers all my needs, with a 50 amp feed from my main panel to the sub panel. :7

:D

[link:www.sonnyedmonds.com | Sonny Edmonds] http://home.earthlink.net/~sonnypie/vortex_smiley.gif
"Precision Firewood Specialist"
God Bless America !
One Nation Under God!

The real problem is the fool behind the tool. :o*
http://home.earthlink.net/~sonnypie/dumfart.jpg

[dmaclusk]

Thanks Sonny! That wraps it all up nicely (for me at least). I didnt' realize the inrush thing could be so high! I figured it'd be 50%-100% over, not 500% over!

[rrich]

There is one advantage to installing a sub panel, it is a lot easier to add additional circuits when the need arises. (Like three weeks after you install your new outlets.)

[JDsharp]

'Nuff said, hey fellas?

Thanks for the finale, Sonny.

jd

[Sonny Edmonds]

Rich,
Ouch!
But hey, if we weren't working on the shop, we'd be working in it.
I think my enjoyment is about 50/50. What doesn't stimulate my surviving brain cells one way, the method to achieve the results does it in another way. ;)

:D

[link:www.sonnyedmonds.com | Sonny Edmonds] http://home.earthlink.net/~sonnypie/vortex_smiley.gif
"Precision Firewood Specialist"
God Bless America !
One Nation Under God!

The real problem is the fool behind the tool. :o*
http://home.earthlink.net/~sonnypie/dumfart.jpg

[arcticfox46]

Sonny,

I agree, working IN the shop, or, working ON the shop give the same amount of enjoyment, except for sanding the sheetrock walls :( . Also when working IN the shop the end result is ususlly a WOW factor :D or a big fat smile on somebodys face :) when you give them the result of working IN the shop.