I'm trying to put together a wiring design for the new shop. I already have
a separate circuit dedicated to lighting. I'm trying to decide what to do
about the circuits to run the tools. I figure on running two 120V/20A
circuits for the smaller stuff. Additionally, I figure on running two
240V/30A circuits. I plan to put the dust collector on one, and the other
tools on the other. The dust collector is packed away in a box at the
moment, so I can't take the specs off the motor (and I can't find them
online), but I'm quite sure a 30A circuit will handle it. I was able to
take the motor specs off the other devices: table saw (230V/8.6A), jointer
(230V/7.1A), and band saw (230V/6A). I don't plan to run more than one of
these other units at the same time. Frankly, I could probably do 20A on the
240V circuits, but I just think 30A would give me more flexibility in the
future if I ever needed to plug in something that needed extra current. The
longest run would be no more than 45 feet. I'm open to comments on the
above.

As for the wiring itself, I think I'm looking at running 3 - #12 wires for
the 120V circuits (2 hots and a shared neutral) and 4 - #10 wires for the
240V circuits (4 hots). No ground as we are required to use metal conduit
around these here parts. Based on the conduit fill chart, I'm looking at
roughly 25% fill with 3/4" EMT. Any reason to bump that to 1"?

Any comments on this plan?

todd

"todd" wrote:

I'm trying to put together a wiring design for the new shop.

You will save money by standardizing on #10AWG for 30A circuits and #12AWG
for 20A circuits.

This will allow you to buy full spools of wire to get best price.

Dedicate a 2P-30A C'bkr for each load. If you do this up front, you will
have taken future expansion into consideration.

If down the road you buy added equipment, then is the time to consider
sharing a receptacle, not now.

Start with a 12/24 load center equipped with a 60A Main.

12/24 translates into 12 full size c'bkrs or 24 half size c,bkrs.

I'd use 1/2 size c'bkrs.

Load the panel full of 2P-30A c'bkrs, then fill remaining spaces with 1P-20A
c'bkrs.

C'bkrs are a relatively low cost item and the price is only going to go up.

If code will alow you, run 3/4" plastic conduit, otherwise you are stuck
running thin wall.

Use double gang boxes and install 2 gang, 20A, duplex receptacles every
8-10ft or closer if the spirit moves you. (This provides 4 outlets/gang box)

Use double gang boxes for the 240V-30A receptacles. You will appreciate the
wiring space.

Running a neutral with the 240V circuits is optional.

It all depends if you need a 120V circuit for the equipment you are using.

DON'T try to double up runs to save some conduit. Sooner or later, it will
come back to bite you.

Run individual conduit runs.

Good luck and have fun.

Lew

..

In article , "todd" wrote:
I'm trying to put together a wiring design for the new shop. I already have
a separate circuit dedicated to lighting. I'm trying to decide what to do
about the circuits to run the tools. I figure on running two 120V/20A
circuits for the smaller stuff. Additionally, I figure on running two
240V/30A circuits. I plan to put the dust collector on one, and the other
tools on the other. The dust collector is packed away in a box at the
moment, so I can't take the specs off the motor (and I can't find them
online), but I'm quite sure a 30A circuit will handle it. I was able to
take the motor specs off the other devices: table saw (230V/8.6A), jointer
(230V/7.1A), and band saw (230V/6A). I don't plan to run more than one of
these other units at the same time. Frankly, I could probably do 20A on the
240V circuits, but I just think 30A would give me more flexibility in the
future if I ever needed to plug in something that needed extra current. The
longest run would be no more than 45 feet. I'm open to comments on the
above.

All sounds good to me.

As for the wiring itself, I think I'm looking at running 3 - #12 wires for
the 120V circuits (2 hots and a shared neutral) and 4 - #10 wires for the
240V circuits (4 hots). No ground as we are required to use metal conduit
around these here parts. Based on the conduit fill chart, I'm looking at
roughly 25% fill with 3/4" EMT. Any reason to bump that to 1"?

Yes -- it will be *much* easier to pull the wires through 1", or even 1-1/4",
EMT than through 3/4".

Any comments on this plan?

Sounds like you've done your homework pretty well.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Sounds pretty good. My comments:
-about "shared neutral" on your
120 volt circuits. That neutral has to carry full load current, so it
should NOT be shared. You could get away with a "shared" green wire,
but you arent'using one.

-It's the 240 volt curcuits where you could "share" a neutral (or go
down a size). I suggest that you DO run a neutral to those boxes.
One of these days you may buy a 240 volt appliance of some sort that
also uses 120 volts, like maybe for a control circuit or a fan. Then
you'd need the neutral.

You didn't say how big your shop is, but I'd consider 120 volt
receptacles every 6 feet, and at 4' height. Every other receptacle
would be on a different circuit. It there more than one door to the
shop? Consider 3-way light switches.

Pete Stanaitis
-----------------------------------------------

Doug Miller wrote:

In article , "todd" wrote:

I'm trying to put together a wiring design for the new shop. I already have
a separate circuit dedicated to lighting. I'm trying to decide what to do
about the circuits to run the tools. I figure on running two 120V/20A
circuits for the smaller stuff. Additionally, I figure on running two
240V/30A circuits. I plan to put the dust collector on one, and the other
tools on the other. The dust collector is packed away in a box at the
moment, so I can't take the specs off the motor (and I can't find them
online), but I'm quite sure a 30A circuit will handle it. I was able to
take the motor specs off the other devices: table saw (230V/8.6A), jointer
(230V/7.1A), and band saw (230V/6A). I don't plan to run more than one of
these other units at the same time. Frankly, I could probably do 20A on the
240V circuits, but I just think 30A would give me more flexibility in the
future if I ever needed to plug in something that needed extra current. The
longest run would be no more than 45 feet. I'm open to comments on the
above.


All sounds good to me.

As for the wiring itself, I think I'm looking at running 3 - #12 wires for
the 120V circuits (2 hots and a shared neutral) and 4 - #10 wires for the
240V circuits (4 hots). No ground as we are required to use metal conduit
around these here parts. Based on the conduit fill chart, I'm looking at
roughly 25% fill with 3/4" EMT. Any reason to bump that to 1"?


Yes -- it will be *much* easier to pull the wires through 1", or even 1-1/4",
EMT than through 3/4".

Any comments on this plan?


Sounds like you've done your homework pretty well.

In article , spaco wrote:
Sounds pretty good. My comments:
-about "shared neutral" on your
120 volt circuits. That neutral has to carry full load current, so it
should NOT be shared. You could get away with a "shared" green wire,
but you arent'using one.

That is incorrect. On a properly installed shared-neutral circuit, the neutral
conductor carries the *difference* between the currents on the two hot
conductors, not their sum. For example, if one side is pulling 12A, and the
other 4A, the current in the neutral conductor is 8A, *not* 16A.

"Properly installed" means with the two hot conductors connected to *opposite*
legs of the 240V service via a double-pole circuit breaker.

-It's the 240 volt curcuits where you could "share" a neutral

Phooey. It's not even needed on the 240V circuits.

(or go down a size).

Incorrect again. The neutral conductor in a branch circuit is not permitted to
be downsized. The *grounding* conductor is, on circuits rated 40A and higher,
but not the neutral.

I suggest that you DO run a neutral to those boxes.
One of these days you may buy a 240 volt appliance of some sort that
also uses 120 volts, like maybe for a control circuit or a fan. Then
you'd need the neutral.

Not too many woodworking machines fall into that category...

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

All good advise above. But consider putting in even MORE outlets. I
have one every 8 feet (length of conduit) around 3 walls, one for
120vac, one for 220vac. And about every other day I wish for an
outlet halfway between! All tools are on rollers except the table
saw, so they get moved around as need be. Guess what limits their
move???

As to height, I put mine at chest height or a little higher. Why
reach down???

One other thing. I'm always needing more 120vac outlets near the main
workbench. I have a 4 plug outlet, one for a heater, one for a radio,
one for a lamp, leaving a single one for Skill saw, power drill, belt
sander, shop vac, and whatever else I come up with. Wish I had put in
a 50 plug outlet!

Hope this helps.

Regards.....

On Nov 5, 12:09 am, "todd" wrote:
I'm trying to put together a wiring design for the new shop. I already have
a separate circuit dedicated to lighting. I'm trying to decide what to do
about the circuits to run the tools. I figure on running two 120V/20A
circuits for the smaller stuff. Additionally, I figure on running two
240V/30A circuits. I plan to put the dust collector on one, and the other
tools on the other. The dust collector is packed away in a box at the
moment, so I can't take the specs off the motor (and I can't find them
online), but I'm quite sure a 30A circuit will handle it. I was able to
take the motor specs off the other devices: table saw (230V/8.6A), jointer
(230V/7.1A), and band saw (230V/6A). I don't plan to run more than one of
these other units at the same time. Frankly, I could probably do 20A on the
240V circuits, but I just think 30A would give me more flexibility in the
future if I ever needed to plug in something that needed extra current. The
longest run would be no more than 45 feet. I'm open to comments on the
above.

As for the wiring itself, I think I'm looking at running 3 - #12 wires for
the 120V circuits (2 hots and a shared neutral) and 4 - #10 wires for the
240V circuits (4 hots). No ground as we are required to use metal conduit
around these here parts. Based on the conduit fill chart, I'm looking at
roughly 25% fill with 3/4" EMT. Any reason to bump that to 1"?

Any comments on this plan?

todd

Todd,
To the advice you've already gotten, I'll add a suggestion to put a
couple of receptacles in the ceiling over your workbench or assembly
area. It's so much better than having cords running across the floor
to reach the middle of the room.

DonkeyHody
"In theory, theory and practice are the same, but in practice they are
not."

"Doug Miller" wrote in message
t...


As for the wiring itself, I think I'm looking at running 3 - #12 wires for
the 120V circuits (2 hots and a shared neutral) and 4 - #10 wires for the
240V circuits (4 hots). No ground as we are required to use metal conduit
around these here parts. Based on the conduit fill chart, I'm looking at
roughly 25% fill with 3/4" EMT. Any reason to bump that to 1"?

Yes -- it will be *much* easier to pull the wires through 1", or even
1-1/4",
EMT than through 3/4".


I'll have to challenge this one Doug. That's not a lot of wire to pull
through 3/4". I'm not even sure 1" or 1 1/4" would be any easier. At the
fill he's going to experience in 3/4", he's really only dealing with the
force of pulling the strands. That will be the same regardless of the
conduit diameter.

--

-Mike-

"Doug Miller" wrote in message
...


That is incorrect. On a properly installed shared-neutral circuit, the
neutral
conductor carries the *difference* between the currents on the two hot
conductors, not their sum. For example, if one side is pulling 12A, and
the
other 4A, the current in the neutral conductor is 8A, *not* 16A.

"Properly installed" means with the two hot conductors connected to
*opposite*
legs of the 240V service via a double-pole circuit breaker.

I hate this practice. It's good if you're the one that ever touches the
wiring, but it sucks if someone else gets into the box and assumes neutrals
for every branch circuit. For a home application, the cost savings in
sharing neutrals is so negligible that it's almost stupid to go this route.
All it takes is someone to get inside the box - even a licensed electrician,
and move a breaker and all bets are off. Just run the neutral for each
branch.



(or go down a size).

Incorrect again. The neutral conductor in a branch circuit is not
permitted to
be downsized. The *grounding* conductor is, on circuits rated 40A and
higher,
but not the neutral.

I'm betting that what he meant here was to downgrade the circuit instead of
what it looked like - reduce the wire size.


--

-Mike-

In article , "Mike Marlow" wrote:

"Doug Miller" wrote in message
et...


As for the wiring itself, I think I'm looking at running 3 - #12 wires for
the 120V circuits (2 hots and a shared neutral) and 4 - #10 wires for the
240V circuits (4 hots). No ground as we are required to use metal conduit
around these here parts. Based on the conduit fill chart, I'm looking at
roughly 25% fill with 3/4" EMT. Any reason to bump that to 1"?

Yes -- it will be *much* easier to pull the wires through 1", or even
1-1/4",
EMT than through 3/4".


I'll have to challenge this one Doug. That's not a lot of wire to pull
through 3/4". I'm not even sure 1" or 1 1/4" would be any easier. At the
fill he's going to experience in 3/4", he's really only dealing with the
force of pulling the strands. That will be the same regardless of the
conduit diameter.

Not really. The wires aren't going to just lay straight in the conduit;
they're going to assume a spiral shape, and there will be friction against the
conduit walls. The bigger the conduit, the easier it is to pull the
conductors. 1-1/4" is probably overkill, but for the modest difference in
price between 3/4" and 1" conduit, I'd use the larger one and save myself some
effort.



--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

In article , "Mike Marlow" wrote:

"Doug Miller" wrote in message
...


That is incorrect. On a properly installed shared-neutral circuit, the
neutral
conductor carries the *difference* between the currents on the two hot
conductors, not their sum. For example, if one side is pulling 12A, and
the
other 4A, the current in the neutral conductor is 8A, *not* 16A.

"Properly installed" means with the two hot conductors connected to *opposite*
legs of the 240V service via a double-pole circuit breaker.

I hate this practice. It's good if you're the one that ever touches the
wiring, but it sucks if someone else gets into the box and assumes neutrals
for every branch circuit.

Anyone who assumes two neutrals for a circuit that comes off of one
double-pole breaker shouldn't be working on AC wiring anyway. :-)

For a home application, the cost savings in
sharing neutrals is so negligible that it's almost stupid to go this route.
All it takes is someone to get inside the box - even a licensed electrician,
and move a breaker and all bets are off. Just run the neutral for each
branch.

Which is one of the reasons I specified using a double-pole breaker: precisely
to eliminate the possibility of moving one side of the circuit to the same leg
as the other side.

The other reason is that with a double-pole breaker, it's not possible to kill
only one side of the circuit (and unknowingly leave the other side live, when
doing maintenance).

(or go down a size).

Incorrect again. The neutral conductor in a branch circuit is not permitted to
be downsized. The *grounding* conductor is, on circuits rated 40A and
higher, but not the neutral.

I'm betting that what he meant here was to downgrade the circuit instead of
what it looked like - reduce the wire size.

Dunno -- looked to me like he meant reduce the wire size, and that's a no-no.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

"Doug Miller" wrote in message
...
In article , "Mike Marlow"
wrote:

"Doug Miller" wrote in message
...


That is incorrect. On a properly installed shared-neutral circuit, the
neutral
conductor carries the *difference* between the currents on the two hot
conductors, not their sum. For example, if one side is pulling 12A, and
the
other 4A, the current in the neutral conductor is 8A, *not* 16A.

"Properly installed" means with the two hot conductors connected to
*opposite*
legs of the 240V service via a double-pole circuit breaker.

I hate this practice. It's good if you're the one that ever touches the
wiring, but it sucks if someone else gets into the box and assumes
neutrals
for every branch circuit.

Anyone who assumes two neutrals for a circuit that comes off of one
double-pole breaker shouldn't be working on AC wiring anyway. :-)

D'oh! Can you believe I read your comments and somehow only saw the
statements preceeding "Properly installed...". Must be an age thing or
sumptin'.


For a home application, the cost savings in
sharing neutrals is so negligible that it's almost stupid to go this
route.
All it takes is someone to get inside the box - even a licensed
electrician,
and move a breaker and all bets are off. Just run the neutral for each
branch.

Which is one of the reasons I specified using a double-pole breaker:
precisely
to eliminate the possibility of moving one side of the circuit to the same
leg
as the other side.


Of course, I would have to have actually seen that in order for it to
register.



--

-Mike-

At least TWO breakers for lighting, and "used" lights shared between them.
That way if the lights go out, there's still enough light to see which way
to move your hand away from the business end of whatever you're using.

I also put a bank of nightlights on EACH of my ckts; can tell at a glance
which is on or not on.
Plus, created a Master Switch just outside the door; when I leave the
shop, NOTHING is powered except lights of one ckt. Takes a few relays, but
not hard to install, especially during the design stage. And, it has a
key-lock switch (kids around).

Pop`


todd wrote:
I'm trying to put together a wiring design for the new shop. I
already have a separate circuit dedicated to lighting. I'm trying to
decide what to do about the circuits to run the tools. I figure on
running two 120V/20A circuits for the smaller stuff. Additionally, I
figure on running two 240V/30A circuits. I plan to put the dust
collector on one, and the other tools on the other. The dust
collector is packed away in a box at the moment, so I can't take the
specs off the motor (and I can't find them online), but I'm quite
sure a 30A circuit will handle it. I was able to take the motor
specs off the other devices: table saw (230V/8.6A), jointer
(230V/7.1A), and band saw (230V/6A). I don't plan to run more than
one of these other units at the same time. Frankly, I could probably
do 20A on the 240V circuits, but I just think 30A would give me more
flexibility in the future if I ever needed to plug in something that
needed extra current. The longest run would be no more than 45 feet.
I'm open to comments on the above.
As for the wiring itself, I think I'm looking at running 3 - #12
wires for the 120V circuits (2 hots and a shared neutral) and 4 - #10
wires for the 240V circuits (4 hots). No ground as we are required
to use metal conduit around these here parts. Based on the conduit
fill chart, I'm looking at roughly 25% fill with 3/4" EMT. Any
reason to bump that to 1"?
Any comments on this plan?

todd

On Mon, 5 Nov 2007 00:09:59 -0600, "todd" wrote:

I'm trying to put together a wiring design for the new shop. I already have
a separate circuit dedicated to lighting. I'm trying to decide what to do
about the circuits to run the tools. I figure on running two 120V/20A
circuits for the smaller stuff. Additionally, I figure on running two
240V/30A circuits. I plan to put the dust collector on one, and the other
tools on the other. The dust collector is packed away in a box at the
moment, so I can't take the specs off the motor (and I can't find them
online), but I'm quite sure a 30A circuit will handle it. I was able to
take the motor specs off the other devices: table saw (230V/8.6A), jointer
(230V/7.1A), and band saw (230V/6A). I don't plan to run more than one of
these other units at the same time. Frankly, I could probably do 20A on the
240V circuits, but I just think 30A would give me more flexibility in the
future if I ever needed to plug in something that needed extra current. The
longest run would be no more than 45 feet. I'm open to comments on the
above.

As for the wiring itself, I think I'm looking at running 3 - #12 wires for
the 120V circuits (2 hots and a shared neutral) and 4 - #10 wires for the
240V circuits (4 hots). No ground as we are required to use metal conduit
around these here parts. Based on the conduit fill chart, I'm looking at
roughly 25% fill with 3/4" EMT. Any reason to bump that to 1"?

Any comments on this plan?

todd


Check your box fill requirements before you decide to run everything
in one conduit unless you like the look of extension boxes.

Mike M