Ya'll helped maked me aware of just how many things one "needs" and "wants"
in a workshop.
I think that separating them into these aptly names categoriies seems like a
good first step.
You helped me set high goals. I think it would be a mistake to wait until
everything is "perfect"
before I start working some wood. I sure have a few projects ahead of me:
grinding concrete floors,
repairing walls, installing more electrical fixtures and lighting and dust
collection, building a workbench.
I'm looking forward to buying some sandpaper, and sharpening my chisels and
trying to create
some nice-looking (2 tone) mortise and tenon joints just to see how well I
can do at it. After that
I may pursue an adjustable outfeed table, workbench and an Arts and Crafts
coffee table and end tables,
not necessarily in that order while I am performing the other upgrades.
This will be my wife and I's first
spring in a house (rather than apartment)..should be fun. Come on winter,
lets get done with it!!!
The Colts lost--if history repeats itself, on one in Indianapolis will say a
word about it tomorrow.
Please excuse my top-posting here. I just wanted to mention that I went
back and reread all of the responses I recieved to my post to the current
thread a month ago and I am actively trying to incorporate some of the
suggestions that were made into my shop design. I'm even learning a bit
about electricity...who would have guessed that a 240v line is powered by
two 120v lines! : )
I've got a 240v line on the outside of the brick garage (previously used by
an RV owner). I'd like to flip the line around for use on the inside and
put 120v instead on the outside. I'm confident about the former, the
latter I'll do if the outlet fixture sizes are compatible enough. Haven't
done my homework on that yet as the idea just occurred to me a few days ago.
I will surely need to take down the wallboard on the uninsulated wall on one
side of the garage for the sake of the electrical improvements. The side
which has our kitchen on the other side surely has insulation, other
electric, plumbing?,etc., behind it. I am less enthused about "messing"
with that wall. I'll have to give that more thought.
My current interior 220v outlet is currently pretty close to the floor.
Does the electrical "code" cite a minimum for that?
BTW, I currently have 3 36" neon lamps..I think I'm going to have 6. Plugs
in the ceiling would be convenient..
Thanks for listening,
You need more outlets. The more the better but at least 3 per wall IMO - I
hate cords strung everywhere. At least two circuits, more better.
The TS in the center is good but you need power for it. As I said, I hate
cords strung everywhere so the outlet for my TS is in the ceiling. There
are both 240v and 120v. Yes, a cord hangs down but at least it isn't always
getting stepped on.
Be sure you have at least eight feet in front of and behind the TS.
You'll undoubtedly be adding bench top tools which implies more benches.
When I build same I incorporate electrical outlets into them so that other
tools or adjacent benches will have conveniently placed outlets.
You need an area to store stuff...sheet goods, lumber, work in progress,
Not having seen your shop, I don't see why you would have any problems.
You are right about the 240v being, essentially, two 120v lines. Unlike
120V, which has a Hot, Common and Ground, the 240 has (or can run on) 2
Hot and a Ground/Common. ( But then so can/does 120V. If you are old
enough, you remember when all plugs only had two prongs.) While your
"could" split a 120V line off your 240V, I would not do it. You
mentioned you had 120V inside the shop, just run it to your current 240V
box (having run the 240v line, of course). You can do this by merely
tying another length of Romex cable to your existing outlet and running
it to the outside box, replacing the 240v socket, which you have already
moved inside, and weatherproof cover plate with ones for a 120v socket
As for your lighting - the more the better, I would definitely upgrade to
6, or maybe even 8 4' fixtures.
You mentioned "Code." That depends on where your live. Here in Alabama,
such mods are very common WITHOUT an inspection. However, for those of
you who live in more governmentally restrictive and union influenced
states, check with your local woodworkers for their advice. (Going to
the local government will invariably give you a "YES" answer, whereas
your woodworking buddies will tell you the truth. ;-) )
For what its worth.
On Sun, 14 Mar 2010 03:21:15 -0400, Bill wrote:
To clarify for OP what could be misinterpreted given it appears little
or no familiarity exists...240V has _only_ two 120V 'hots' and an
associated ground, _no_ neutral.
Three wire appliance outlets (no longer NEC Code-compliant, now need
four) utilized the ground conductor as the 120V neutral as well for the
120V (components like motor, light, etc.) but the 240V heater coil is
tied directly across the two hot and isn't anywhere connected to a
"neutral". Ditto for 240V motors; there's a third wire but it's ground,
not neutral and the motor doesn't care whether it's there or not.
To go on for OP who seemed surprised to learn what 240V comprises, the
240V is generated by tapping from a transformer at such points that one
leg is 180-deg out of phase (in time) w/ the other so when one leg is at
the positive sine peak the other is at it's negative max. The RMS
difference between these is then the 240V your voltmeter sees while each
(being AC) measures 120V to a neutral. While these are commonly called
"phases", the phase there is the time shift within a single one of the
three phase generation phases from the powerco. It's still single-phase
Thank you for the lessons in electricity! I take it I should be installing
"4-wire" outlets if I'm
planning to purchase new 220v tools from Delta or Grizzly, correct?
I've done a bit of reading, so I'm not as naive as I was a week ago, but I
was surprised to learn:
"240V is generated by tapping from a transformer at such points that one
I have also learned about 3-phase power and the correspondance to induction
motors so this makes sense to
me in that context--expecially in that the hot lines to coils in the motor
will be hooked up in parallel rather than in series as in 120v
(that is the most sophisticated statement I can make about this matter at
this point and I offer it only as an indication of my level of preparedness
which is weak due to limited experience. I expect I can do this project if
I proceed cautiously).
I probably should examine a book (on setting up/modifying new existing
lines). Any suggestions regarding a book? I recall seeing a few books on
wiring at the BORGs.
Not for "ordinary" 240V outlets, no. The four-wire connection is for
things like appliances that have both 240V and 120V loads that _used_ to
share the grounding conductor for the 120V neutral. A power saw, etc.,
that is just a 240V motor load doesn't have any use for the 120V and so
doesn't need anything other than the usual 3-wire 240V.
Used to be stuff like drill presses, etc., had a 120V accessory light
that was powered by one side of the 240V in a similar fashion but it
seems based on some other postings here that they've quit doing that in
one of two ways -- either no more courtesy light or it requires a 240V bulb.
OBTW, this is for US 120V/240V obviously, the UK and others run 240V as
does the US 120V w/ a single hot/neutral and don't have 120V routinely
(which is why ordinary US appliances are of essentially no value over
there, of course... :) ).
I better let somebody else recommend recent books rather than guess --
I'm so much an old fogey the most recent thing I have dates to the 80s
maybe at the latest and may well be 20 yrs older than that, even, I'm
not sure... :)
I know most of the biggest new restrictions in the NEC simply by word of
mouth; I also tend to ignore most of them here on the farm and in the
shop figuring if it's been good enough for 50 years or so it couldn't
have been _too_ bad... :) That, of course, isn't to be taken as a
recommendation against following Code in new work...
Nope ... most 220/240v woodworking tools in North America only need a
total of 3 wires to both work properly and comply with code.
The three wires needed for 220/240v operation are: Two hot wires (one
from each hot leg of the service/sub panel), and one ground wire. The
ground wire, while not necessary to power the equipment, is necessary
for safety and code compliance.
The "four wire" cables/installations you mentioned are used for 220/240v
appliances (like stoves and dryers) that are also equipped with timers,
lights, etc, and that operate on 120v.
That said, there might be the ocassional woodworking tool that requires
120v also for lights and/or speed control circuits, etc ... so do your
homework before attempting to wire.
If you have one of these 4 wire circuits and don't need the extra wire,
then simply use the two hots wires, usually black and red (which
can/should be verified at the c'bkr) and the ground wire; and put a wire
nut/tape on the end of the neutral/white wire in the receptacle.
NOTE: some 220/240v circuits use "2 wire w/ground".
In this case the white, neutral, wire can be used as one of the two
necessary hot wires but it must be clearly marked on both ends, at the
c'bkr and the receptacle (generally with a wrap of black tape), so that
those coming after you know it is indeed being used as as a "hot" wire.
Most of those are well worth the price paid for a DIY'er. Don't confuse
yourself with learning about 3 phase power unless you have a need; take
your time, understand and think about what you're doing and don't do it
until you do ... it is not a bad idea for a home/shop owner to turn off
the power to the ENTIRE structure when doing electrical work (and if you
can lock up the service panel so that only you have access while doing
the work, so much the better).
Isn't the ground, then, "completing the circuit" in this case?
BTW, I noticed that my outlet on the outside has a single 30 Amp breaker
and that the interior one has a double 50-Amp breaker (s). The 30 Amp one
on the outside
was used by the previously owner for his RV and the interior one for
My biggest tool will be a 3HP TS which Grizzly suggests a 20 Amp circuit
for. My thought was to
put a Delta 1.5 HP DC on the 30 Amp line and a series of outlets along a
wall that would support
other 220v machinery (including the TS). It seems like the 50-Amp circuit
would support several machines, one-at-a-time,
with the possible future attachment of things like a heater, for example,
later if desired.
Additionally, I'd add another 120v line for the same wall (outlets about 4
feet apart) and provide another
120v line for use by the workbench (tools).
Currently, my garage lights and outlets share a line with with the kitchen
outlets, and it is nice that a pair of
garage lights come on with the flip of a switch from the kitchen. I may add
another line for the
ceiling which would support 4 florescent lights and for whatever tool might
be convenient to plug in there.
So, that would proivde me with a total of 3 120v lines and 2 240v lines for
tools and would leave me with 3 empty slots in my junction box. Some person
dedicated two 120v lines to power 2 separate bedroom ceiling fans (seems
like a waste). Powering them from other existing circuits is probably not
worth the bother since I don't know how to easily do it. Powering them
together with one circuit may be worth considering, if necessary! If
nothing else, it would give me something to do in my free time after I
finish grinding and epoxying the floor. ; )
SWMBO is ready to see furniture being made! ; ) She doesn't see this as
all being part of the process.
Every time I come back here I think this through a little further..I'm going
to print this out so I don't forget! ; )
That's what I said earlier and Swing just reiterated -- the ground for a
240V-only motor/appliance/heater/whatever is _purely_ a safety ground.
Remove it and the operation of the device will be totally unaffected.
The only purpose it serves is to ground the case in the event of a fault
that would somehow otherwise energize it.
The circuit is completed between the two legs -- remember, this is AC
and my description of the way in which the voltages are generated as
being tapped from different points on the transformer so one leg is
positive while the other is negative (at the peaks, since the driving
voltage is a sine wave they're both varying continuously but always with
this same 180-degree lag of one relative to the other). Owing to that,
one is always positive with respect to the other (except at the instant
of crossing, of course, and w/ a varying amplitude that is in RMS terms
the 240V) and the current flows from the higher to the lower thru the
device, the direction and magnitude at any time depending on that
varying potential and the load characteristics. Hence the ground in the
240V-only case never sees any current flow at all and can be dispensed
with except for the safety reasons.
The difference is in the split-voltage 120/240V case where there's a
device of both voltages on three-wire service. Then, since the 120V
device _does_ have to have a return, the ground conductor also serves
that role. As noted earlier, that is what the NEC has now outlawed
requiring 4-conductor service to keep the 120V neutral and the safety
ground separate to serve their individual functions.
The 50A service is more than adequate for everything you'll likely ever
have in the shop (other than perhaps if you add a bunch of electric
heat). The rub is, Code won't allow putting a 20A or 30A outlet on a
circuit protected for more than the rating of the outlet (for obvious
reasons if you think about it (and this is one that I _wouldn't_ break
despite my previous comments :) ) ).
I don't know if you could find 50A standard configuration 240V outlets;
would doubt it. OTOMH, the options I'd see would be
a) Swap the 50A breaker for the rating of outlet(s) you want to use
(Code is happy if conductors are larger than allowed minimums for any
given size breaker),
b) Put in a small subpanel to feed the convenience outlets and wire them
w/ 10g or whatever is appropriate for the chosen feeder breaker for the
Okay, I got it now! I think we only studied DC circuits in electronics
class in H.S. ; )
I didn't realize the elevated-sophistication of 240v power compared to
I like option (b) if I can power the subpanel with the 50 amp line. Thank
you for pointing
out the issue beween the 240V outlets and the 50A power line. I'll take a
look at what type of outlet is on it now (and I'm not sure if welders use a
special 50A outlet or not).
Thank you for your help!
Just as a FWIW, let me admit to a minor boondoggle I did long ago.
Let's just say that I have a bit of experience as an electrician
wiring homes in the 60's, as a builder and as a woodworker.
However, I can also screw up and am not ashamed to admit it.
When I wired my own shop, I pulled in a 60a line to a load center
in my shop from my main household breaker box. I then got a
6-circuit little load center box and connected it up without much
thought. The box had 3 breakouts on the left and 3 breakouts on
the right. It was only when I began installing some tools that it
hit me like a ton of rocks: that's just 2 normal DP breakers and
2 SP breakers. In my own case, it was a simple task to pull out
the little box and substitute in a 12 circuit box with 6 knockouts
on each side. The little box became a load center on one of the
Lowest cost, highest flexibility as follows:
125A MLO (Main Lug Only) 12/24 (12-1" poles/24;1/2" poles)
Load Center equipped with a 2P-60A Main c'bkr kit, neutral bar,
and insulated ground bar.
The above has enough capacity for almost any shop including
a fairly good sized commercial shop.
Install 2P-30A branch c'bkr for each 240V stationary tool along with
a 2P-30A, non fused disconnect at (within 10ft) the tool.
If you are going to work on a tool, padlock the disconnect switch
in the OFF position with a padlock that has only ONE KEY,
which is in your pocket.
The above is a standard industrial safety practice.
Simple, neat, and low cost.
Some of what I've learned since I read Lew's post the first time:
Evidentally, a load center is "Main Lug Only" when it doesn't have
it's own main breaker like the primary load center would probably have.
Load Units, such as made by Eator Cutler-Hammer use descriptions such as "12
spaces, 24 circuits".
If I learned part of my lesson yesterday, the only way you'd get 24 circuits
would be to use 1 Hot
and a 1 Common for every circuit. Is it typical for someone put two such
circuits under a single breaker--probably
not in a shop environment, huh? Even "lighting" seem too important to mess
So you use 2 spaces for a 2P-30A branch For Each 240v stationary tool in the
load center. So with four 240v tools
one is basically left with room for 4 or 8 120v lines. This raises the
question: Which is better--two circuits with 1 outlet each from 1 breaker or
one circuit with 2 outlets on one breaker? I think the former--for the
same reason Lew only wants one 240v tool on each line. This creates a new
question for me: in what sense does a 15A breaker support two different
circuits? Specifically, does
it only support the sum of the amperages of the two circuits?
I try to learn Something New everyday. Today was certainly no exception!
Got to hit the hay for tomorrow's another day!
I just wished to double-check that this was supposed to be
"Install 2P-30A branch c'bkr for each 240V stationary tool along with
non fused disconnect at (within 10ft) the tool."
This is correct, right? Is is fair to assume that most 15A tools also
have a fuse or internal shut-off system of their own?
I really feel I am close to knowing everything I will need to wire a
subpanel, some minor but important details concerning wire size, etc., I
can easily look up (I will err on the side of safety).
Meeting all code requirements raises the bar higher. For instance, I
haven't investigated whether one's conduit is expected to covered by
wallboard. Someone suggested that panels and subpanels are supposed to
have a front/backing board for instance (to cover/protect some of the
I wish to note that I appreciate the kind, thoughtful and useful help
that I have received here. Learning how to do new things (or even old
things, like constructing a wooden plane) seems to raise my
happiness-quotient. : )
IME, don't even bother with 15 amp circuits, except maybe for lights.
In many locales today at least 12 ga wire is required throughout, and it
is simply too easy to use 12 ga and go with 20 amp c'brks for your 120v
Not really enough of a cost savings for the ultimate flexibility benefit.
That's exactly what I was planning to do--I'm prudently choosing safety
over (false!) economy. I expect that such decisions will nullify such
factors such as a temperature of 10 degrees in the winter and 95
degrees in the summer... But, by all means, please stop me if I expect
something wrongly! :)
BTW, the IM for the 15A saw I was looking at suggests putting the saw on
a 20A circuit.
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