I'm in the planning stage of my electrical wiring within my shop. I'm going
to be placing separate 220v circuits about the shop. What amperage should I
use? BTW, I already have my PSI switched to 220 and have a 20 amp circuit
in place for that . The rest of my equipment is still 110 but in the
future, I see a cabinet saw and jointer that could be run on 220. TIA
--
Tim
--------
See my page @ http://www.wood-workers.com/users/timv/ (seriously needs
updating)
Igor wrote:
>
> Are you talking about the stab holes in the back for 10 ga wire?
They "stab" into the back but the resemblance to the fire hazard cheap
sockets ends there. The industrial or "spec" grade use the side screw to
clamp the wire once it is inserted into the back. The cheap sockets use
a small bent spring to hold the wire in place.
-Bruce
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IME, just about anything you can convert to 220, and most 220v shop tools,
will run on a 220v, 20A circuit. Might want at least one 30 A for a dust
collection system..
FWIW, I used 10 ga wire on all my 220v circuits, even the 20 A circuits ...
that way I have a choice of going to 30 A with a breaker and new receptacle
if/when the need arises.
Doing it now, while you have a case of the endeavors, is the best bet ...
DAMHIK.
--
www.e-woodshop.net
Last update: 8/11/03
"Tim V" wrote in message
> I'm in the planning stage of my electrical wiring within my shop. I'm
going
> to be placing separate 220v circuits about the shop. What amperage should
I
> use? BTW, I already have my PSI switched to 220 and have a 20 amp circuit
> in place for that . The rest of my equipment is still 110 but in the
> future, I see a cabinet saw and jointer that could be run on 220. TIA
"Steve Wolfe" writes:
> The few 5-HP machines I've looked at have had maximum amp draws of
> around 27 amps, a 30-amp 220 circuit will run them just fine.
Not true.
The allowable full load for a c'bkr in an enclosure such as a panelboard is
80% of the nameplate value.
The 100% rating is for a c'bkr in open air only.
Thus a 30A c'bkr is rated to handle 24A on a continuous basis which is why
you need a 40A c'bkr for that 27 FLA motor.
> As for handling the inrush current without tripping the breaker, I
> wouldn't worry. I haven't seen a breaker yet that isn't EXTREMELY
> generous at tripping. The brand-new, 20-amp circuit breakers that I've
> tested have taken as long as 5 minutes to trip when put under *30* amp
> draws. I've heard people telling horror stories about Square-D breakers,
> but none of these were Square-D. I've come to believe that they're all
> that way. Maybe I'm wrong, maybe there are some "strict" breakers out
> there, but I sure haven't been able to find them from Square-D, GE, or
> ITE/Siemens! Of course, as the current draw gets higher, they trip more
> quickly.
Unless you have about $100,000.00 of rather sophisticated test equipment at
your disposal, you will be unable to properly test c'bkrs.
--
Lew
S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: <http://home.earthlink.net/~lewhodgett> for Pictures
> I'd run #10 AWG wire with 2P-30A c'bkrs for everything except say a 5HP
air
> compressor which will require a 2P-40A and #8 AWG to handle the inrush.
The few 5-HP machines I've looked at have had maximum amp draws of
around 27 amps, a 30-amp 220 circuit will run them just fine.
As for handling the inrush current without tripping the breaker, I
wouldn't worry. I haven't seen a breaker yet that isn't EXTREMELY
generous at tripping. The brand-new, 20-amp circuit breakers that I've
tested have taken as long as 5 minutes to trip when put under *30* amp
draws. I've heard people telling horror stories about Square-D breakers,
but none of these were Square-D. I've come to believe that they're all
that way. Maybe I'm wrong, maybe there are some "strict" breakers out
there, but I sure haven't been able to find them from Square-D, GE, or
ITE/Siemens! Of course, as the current draw gets higher, they trip more
quickly.
steve
...think previous post already had the answer...converting 120v motor to
240v isn't going to change the answer at all if the existing stuff runs ok
on 120v. Great idea about using 10g wire though...not that much more $$$
per foot as long as you are at it and don't have any serious bends to make.
"Doug Miller" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, "Tim V"
<[email protected]> wrote:
> >I'm in the planning stage of my electrical wiring within my shop. I'm
going
> >to be placing separate 220v circuits about the shop. What amperage
should I
> >use? BTW, I already have my PSI switched to 220 and have a 20 amp
circuit
> >in place for that . The rest of my equipment is still 110 but in the
> >future, I see a cabinet saw and jointer that could be run on 220. TIA
> >
> What amperage do the cabinet saw and jointer require? That's what you
should
> provide.
>
> --
> Regards,
> Doug Miller (alphageek-at-milmac-dot-com)
> ...think previous post already had the answer...converting 120v motor to
> 240v isn't going to change the answer at all if the existing stuff runs
ok
> on 120v. Great idea about using 10g wire though...not that much more
$$$
> per foot as long as you are at it and don't have any serious bends to
make.
I've noticed that going from 12-gauge to 10-gauge is quite a bit more
expensive, unless (perhaps) you're buying in 1,000-foot spools. Places
around here practically give 12-gauge away at a loss just to get you in
the store. But again, 10-gauge is a good idea anyway!
steve
"Steve Wolfe" writes:
> How is measuring the current draw, and seeing how long it takes to trip
> not "proper"?
No problem with that procedure as far as it goes; however, you are dealing
with a thermal-magnetic c'bkr.
To check the thermal portion of the c'bkr, requires as you suggest, applying
a controlled current and measuring the time required to trip; however, it
also requires controlling the ambient temperature while testing.
Since the thermal trip curve represents and inversely proportional
relationship, it require multiple test points to get a complete picture.
Translation:
It's a PITA, time consuming test since you must wait for the c'bkr to cool
down after a test before you can run the test at a different test point.
Testing the "magnetic" portion of the c'bkr is a whole different kettle of
fish which your applying a current and measuring the time to trip doesn't
address.
It requires very high currents and high speed recording devices, all very
expensive.
I once saw a film of a 3P-100A safety disconnect switch that had a bolted
fault wired on the secondary side (Literally a copper bar bolted across the
terminals) that had a 100,000 amp current applied to it.
The camera that recorded the event was behind a special piece of bullet
proof glass.
The safety switch exploded right in front of the camera like a bomb had
exploded inside the switch.
If the camera had not been behind that glass, it would have been history.
It was an attempt to demonstrate the effects of high current short circuits,
and IMHO, was very effective.
BTW, the lab where that test was run cost over $1,000,000.00 to build 20
years ago.
HTH
--
Lew
S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: <http://home.earthlink.net/~lewhodgett> for Pictures
"Larry Jaques" writes:
> NO, they're the industrial style with screws and a
> wavy plate which catches the wire. MUCH safer.
>
> I have no idea how OSHA or the sparky's union ever let
> the stab outlet style into production. Talk a bout a fire
> hazard!
They are what we used to refer as "strip & stuff" for the residential
market.
It is strictly a cheap and dirty product.
I've lost all track of pricing over the years but if somebody told me a
contractor bought 10,000 pieces for less than $0.35-$0.40 each, I wouldn't
be the least bit surprised.
--
Lew
S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: <http://home.earthlink.net/~lewhodgett> for Pictures
Watch your conduit size, number of wires and number of bends with that 10 ga
wire. The stuff is a bit harder to pull then 14 or 12 ga. Use condulettes or
boxes instead of pulling ells. IMHO!
"Steve Wolfe" <[email protected]> wrote in message
news:[email protected]...
> > ...think previous post already had the answer...converting 120v motor to
> > 240v isn't going to change the answer at all if the existing stuff runs
> ok
> > on 120v. Great idea about using 10g wire though...not that much more
> $$$
> > per foot as long as you are at it and don't have any serious bends to
> make.
>
> I've noticed that going from 12-gauge to 10-gauge is quite a bit more
> expensive, unless (perhaps) you're buying in 1,000-foot spools. Places
> around here practically give 12-gauge away at a loss just to get you in
> the store. But again, 10-gauge is a good idea anyway!
>
> steve
>
>
>
Older motors are not as efficient as the newer ones. It may have a higher
inrush current as well. Besides, you shouldn't be running a 28amp max
machine on a 20 amp circuit.
"Chris Merrill" <[email protected]> wrote in message
news:[email protected]...
> Steve Wolfe wrote:
> > As for handling the inrush current without tripping the breaker, I
> > wouldn't worry. I haven't seen a breaker yet that isn't EXTREMELY
> > generous at tripping. The brand-new, 20-amp circuit breakers that I've
> > tested have taken as long as 5 minutes to trip when put under *30* amp
> > draws. I've heard people telling horror stories about Square-D
breakers,
>
> Hmmm...when I tried wiring my 3HP planer for 110 (to run temporarily until
> I could run a 220 line), it tripped the breaker instantly, EVERY time I
hit
> the ON button. It was on a 20amp circuit...and the motor plate claimed 28
> amp max draw.
>
> It was, however, an _old_ machine...do induction motors draw
> more current as they age?
>
> C
>
> ************************************
> Chris Merrill
> [email protected]
> (remove the ZZZ to contact me)
> ************************************
>
On Wed, 13 Aug 2003 20:28:57 GMT, "Lew Hodgett" <[email protected]>
wrote:
>
>That's one of the reasons you can get back wired as opposed to side wired
>devices.
>
>They are usually industrial or hospital grade and thus are a little more
>expensive than commercial grade devices sold at Home Depot.
Are you talking about the stab holes in the back for 10 ga wire?
In article <[email protected]>, "Tim V" <[email protected]> wrote:
>I'm in the planning stage of my electrical wiring within my shop. I'm going
>to be placing separate 220v circuits about the shop. What amperage should I
>use? BTW, I already have my PSI switched to 220 and have a 20 amp circuit
>in place for that . The rest of my equipment is still 110 but in the
>future, I see a cabinet saw and jointer that could be run on 220. TIA
>
What amperage do the cabinet saw and jointer require? That's what you should
provide.
--
Regards,
Doug Miller (alphageek-at-milmac-dot-com)
"Larry Jaques" writes:
> MAN that
> 10ga stuff is hard to wind around an outlet or switch terminal!
That's one of the reasons you can get back wired as opposed to side wired
devices.
They are usually industrial or hospital grade and thus are a little more
expensive than commercial grade devices sold at Home Depot.
--
Lew
S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: <http://home.earthlink.net/~lewhodgett> for Pictures
"Tom Kohlman" <[email protected]> wrote:
> I had it explained to me once that juice runs on the outside of the wire,
> not through it.
That's certainly true for very long wires (i.e. transmission lines)
and/or high frequencies. I suspect it's not true for the length runs
you're likely to find in a residential wiring job.
I did a quick google search on "skin effect" and came up with a few
references filled with more calculus than my few remaining brain cells
are still capable of dealing with. Here's one reasonable reference:
http://whatis.techtarget.com/definition/0,,sid9_gci541369,00.html
but I think the short answer is that at 60 Hz and a few hundred feet of
wire, it's just not an issue.
On Thu, 14 Aug 2003 19:14:04 GMT, Igor <[email protected]>
pixelated:
>On Wed, 13 Aug 2003 20:28:57 GMT, "Lew Hodgett" <[email protected]>
>wrote:
>>
>>That's one of the reasons you can get back wired as opposed to side wired
>>devices.
>>
>>They are usually industrial or hospital grade and thus are a little more
>>expensive than commercial grade devices sold at Home Depot.
>
>Are you talking about the stab holes in the back for 10 ga wire?
NO, they're the industrial style with screws and a
wavy plate which catches the wire. MUCH safer.
I have no idea how OSHA or the sparky's union ever let
the stab outlet style into production. Talk a bout a fire
hazard!
-
Press HERE to arm. (Release to detonate.)
-----------
http://diversify.com Website Application Programming
On Wed, 13 Aug 2003 10:04:01 -0600, "Steve Wolfe" <[email protected]>
pixelated:
>> ...think previous post already had the answer...converting 120v motor to
>> 240v isn't going to change the answer at all if the existing stuff runs
>ok
>> on 120v. Great idea about using 10g wire though...not that much more
>$$$
>> per foot as long as you are at it and don't have any serious bends to
>make.
>
> I've noticed that going from 12-gauge to 10-gauge is quite a bit more
>expensive, unless (perhaps) you're buying in 1,000-foot spools. Places
>around here practically give 12-gauge away at a loss just to get you in
>the store. But again, 10-gauge is a good idea anyway!
I got a 250' spool of 12/2 grounded for $20. The 10/2g was $35 or
something for 250', and even less per foot in 1k' spools. MAN that
10ga stuff is hard to wind around an outlet or switch terminal! I
had to resort to REAL needlenose pliers when I installed the 10/3
A/C feed wiring while the old Xcelite (electronics) needlenose pair
worked fine with the 12ga. I think the 10/3 was $0.49/ft, quite a
bit more expensive for 25'.
-
Press HERE to arm. (Release to detonate.)
-----------
http://diversify.com Website Application Programming
Circuit breakers are designed to operate as you describe - the larger the
fault the faster it trips - that's by design. I like the fact that you
"tested" the 20 amp breaker. You cannot test a breaker without a specific
breaker tester - and trust me - you don't have the money to buy one. If you
want to see how fast a breaker is supposed to trip - request a breaker curve
from the manufacturer. Breakers protect wires/insulation. If you wish to
protect the motors on your woodworking equipment, you need proper
coordinated overload protection on a motor specific starter. Realistically -
the motor we use on woodworking machines - especially single phase models
aren't really worth protecting. You can buy a $20 bimetallic overload
protector and never have a problem.
"Steve Wolfe" <[email protected]> wrote in message
news:[email protected]...
> > I'd run #10 AWG wire with 2P-30A c'bkrs for everything except say a 5HP
> air
> > compressor which will require a 2P-40A and #8 AWG to handle the inrush.
>
> The few 5-HP machines I've looked at have had maximum amp draws of
> around 27 amps, a 30-amp 220 circuit will run them just fine.
>
> As for handling the inrush current without tripping the breaker, I
> wouldn't worry. I haven't seen a breaker yet that isn't EXTREMELY
> generous at tripping. The brand-new, 20-amp circuit breakers that I've
> tested have taken as long as 5 minutes to trip when put under *30* amp
> draws. I've heard people telling horror stories about Square-D breakers,
> but none of these were Square-D. I've come to believe that they're all
> that way. Maybe I'm wrong, maybe there are some "strict" breakers out
> there, but I sure haven't been able to find them from Square-D, GE, or
> ITE/Siemens! Of course, as the current draw gets higher, they trip more
> quickly.
>
> steve
>
>
>
>Realistically -
>the motor we use on woodworking machines - especially single phase models
>aren't really worth protecting. You can buy a $20 bimetallic overload
>protector and never have a problem.
Most consumer motors have internal overload protection. Look at the nameplate
or look for a sticker. If the motor is not internally protected in a piece of
equipment there will be an external protector. They won't get the U/L (or other
recognized testing lab) certification for cord and plug connected equipment
without it.
"Tim V" writes:
> I'm in the planning stage of my electrical wiring within my shop. I'm
going
> to be placing separate 220v circuits about the shop. What amperage should
I
> use?
I'd run #10 AWG wire with 2P-30A c'bkrs for everything except say a 5HP air
compressor which will require a 2P-40A and #8 AWG to handle the inrush.
Remember one thing, the c'bkr protects the insulation on the down stream
wire, not the load connected to it.
As far as NEC is concerned, that $1,000.00 tool can go up in smoke as long
as the insulation on the wire feeding it is protected.
Protecting that $1,000.00 tool requires the installation of an overload
relay which is a whole different kettle of fish.
HTH
--
Lew
S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: <http://home.earthlink.net/~lewhodgett> for Pictures
On Thu, 14 Aug 2003 19:24:35 -0700, Larry Jaques <jake@di\/ersify.com>
wrote:
>NO, they're the industrial style with screws and a
>wavy plate which catches the wire. MUCH safer.
>
>I have no idea how OSHA or the sparky's union ever let
>the stab outlet style into production. Talk a bout a fire
>hazard!
>
It is interesting to me that in Denmark, where I spent some time, they do
not have wire nuts. Instead they use a plastic-covered metal tube with set
screws -- like I have seen on a wiring block but I cannot remember the name
-- and you put the wires in from either end. At first I thought it was too
cumbersome and expensive (a simple switch box there was >$6) but then I
realized that there was unlikely to be a problem when bending the wire back
into the box and having the connector fall off. (It is also easier over
there because w/ 220 the wire is half the size.) It seems much, much safer
than our wire nuts. In fact, I'd like to use them here in the US if I
could find them and they were legal.
>they use a plastic-covered metal tube with set
>screws - <snip>
>I'd like to use them here in the US if I
>could find them and they were legal.
You will see these in commercial wiring too but usually only on larger sized
conductors. There are some listed down to 14ga wire so they are "legal", just
pricy.
"Chris writes:
> Hmmm...when I tried wiring my 3HP planer for 110 (to run temporarily until
> I could run a 220 line), it tripped the breaker instantly, EVERY time I
hit
> the ON button. It was on a 20amp circuit...and the motor plate claimed 28
> amp max draw.
>
> It was, however, an _old_ machine...do induction motors draw
> more current as they age?
Something to keep in mind.
The locked rotor starting current of a motor can be in the order of 6-10
times the nameplate FLA of the motor.
Using your example above, the inrush current could have been as high as 280
amps for perhaps as long as 1/2 second.
No wonder you tripped that little 1P-20A c'bkr.
--
Lew
S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: <http://home.earthlink.net/~lewhodgett> for Pictures