Larry Jaques writes:
On Wed, 08 Dec 2010 14:39:26 -0800, Mike M
wrote:

On Tue, 07 Dec 2010 20:17:50 -0800, Larry Jaques
wrote:

On Tue, 07 Dec 2010 13:16:11 -0500, wrote:

On Mon, 06 Dec 2010 23:02:40 -0500, Bill wrote:

Scott Lurndal wrote:
writes:

To avoid "cycling the breakers", Lew advised running 12-3 from two 20
Amp breakers (it would not have occurred to me to do that).

I'm not sure what this means, but if you're running two 120v circuits
using 12-3 from a pair of 20A breakers, make sure the breaker handles
are tied together such that both trip if either one trips.

scott

Because???

Because 1) - it is code.

Show me code in any country which demands tied circuit breaker handles
for 120v circuits. I double dog dare you!


2) if one circuit trips and you assume the wire is "dead" you
could be - the black could be dead, and the red live, and a lifted
neutral (which is common to both) would be LIVE.

We're talking 120v here, not 240, clare. With 240v, both phases are
going to the same box. Here, there are separate circuits and boxes
with a single phase going to each.



210.4 Multiwire Branch Circuits.
(A) General. Branch circuits recognized by this article
shall be permitted as multiwire circuits. A multiwire circuit
shall be permitted to be considered as multiple circuits. All
conductors of a multiwire branch circuit shall originate
from the same panelboard or similar distribution equipment.
FPN: A 3-phase, 4-wire, wye-connected power system
used to supply power to nonlinear loads may necessitate
that the power system design allow for the possibility of
high harmonic currents on the neutral conductor.
(B) Disconnecting Means. Each multiwire branch circuit
shall be provided with a means that will simultaneously
disconnect all ungrounded conductors at the point where
the branch circuit originates.
(C) Line-to-Neutral Loads. Multiwire branch circuits
shall supply only line-to-neutral loads.
Exception No. 1: A multiwire branch circuit that supplies
only one utilization equipment.
Exception No. 2: Where all ungrounded conductors of the
multiwire branch circuit are opened simultaneously by the
branch-circuit overcurrent device.
FPN: See 300.13(B) for continuity of grounded conductor
on multiwire circuits.
(D) Grouping. The ungrounded and grounded conductors
of each multiwire branch circuit shall be grouped by wire
ties or similar means in at least one location within the
panelboard or other point of origination.
Exception: The requirement for grouping shall not apply if
the circuit enters from a cable or raceway unique to the
circuit that makes the grouping obvious.
ARTICLE 210—BRANCH CIRCUITS 210.4
2008 Edition NATIONAL ELECTRICAL CODE

Mike, can you point out the particular text in that extract which
states the demand to tie two 120v breakers together when supplying
120v equipment?


210.4(B) of course.

scott

Nova wrote:

Bill wrote:

Nova wrote:

Mike Marlow wrote:


Oh hell - we all learn from each other's posts. The true beauty (and
the original intent...) of newsgroups. Wiring in conduit is nothing
major. Don't read into what you read too much. It's really
straightforward stuff. So... now that you're thinking about using
conduit - go out and buy yourself a 1/2" EMT bender. While away the
hours between now and mid-March, studying how to bend EMT, practicing
it, learning how to quickly get rid of those nasty pretzel bends that
you'll be guaranteed to make in the beginning, and by mid-March,
you'll be up on your ladder hanging conduit. You'll love it - it has
such an industrial look. Really impresses the chicks...


It would take me until mid-March to get one "box offset" done right. I
suck at bending conduit.


Uh oh. LOL!
It's got to be easier than taping a decent drywall joint--at least I
hope it is! : )

Bill


Let me put it this way... that Ecnerwal's advise in a previous post and
buy the die cast offset. He's also right about pulling 8 - #12's
through 1/2" EMT. The NEC allows 9 but it's a bitch if it's anything
other than a straight, short pull.


That should have read "Take Ecnerwal's advise..."

--
Jack Novak
Buffalo, NY - USA

Bill writes:
Ecnerwal wrote:
- you'll need
a lot of fixtures to warrant #12 and a 20 amp 240V circuit, .vs. #14 and
a 15 amp circuit.) At half an amp or so per 4-lamp F32T8 ballast at
240V, 24 ballasts (circuit derated to 80% for being on a long time) and
96 tubes (384 feet, if you like) on one circuit and 14 ga wire. For that
matter I'm danged if I know why folks are talking 12Ga wire on a
lighting-only circuit that might, at most, be 16 two-tube fixtures, and
probably won't even be that. Unless the ballasts are terrible (awful
power factor, inefficient) that should normally be well within the
capacity of a single 15 amp 120V circuit - and if being split in twain
so that they don't all go out at once (which, if it is really a lighting
only circuit, is far from likely in my experience, but I respect it as a
design goal) it's even more blatantly inside the reach of a 15 amp 120V
circuit to run half or 2/3's of that load on 14Ga wire.

I do overkill, but I try to avoid _stupid_ levels of overkill when it
costs me serious money. 20 amp breakers and/or 12ga wire to feed 2-lamp
4-foot fixtures in this quantity seems rather stupid, even for me - and
I have most of 1000 feet of 12-2NM I happened to buy back when it cost
$118.

Please see if my math makes sense:

Amps/fixture = (32w + 32w)/120v .6.

There is some loss in the ballast. The ballast will have a rating
plate that documents the maximum load in kva. The graingers catalog
should list kva ratings for most fixtures. Looks like the typical
shop light with F34T12 lamps is 40 fixture watts per ea.

scott

On Wed, 08 Dec 2010 19:43:32 -0500, Bill wrote:

Mike Marlow wrote:
I bet you find
you've been making a mountain out of a mole hill here.

I hope so. But, from my vantage point, the part about how to wire a
bunch of fixtures in parallel, properly, was a decent-sized mole hill!

Didn't you just wire outlets in parallel before putting in your
drywall? It's exactly the same but there is a switch between the
panel and fixtures.

--
Invest in America: Buy a CONgresscritter today!

On Wed, 08 Dec 2010 07:17:09 -0700, Doug Winterburn
wrote:

On 12/08/2010 06:32 AM, Markem wrote:
On Tue, 07 Dec 2010 21:06:47 -0700, Doug Winterburn
wrote:

OK, the two hots are 180 degrees out of phase with respect to the
center-tap/neutral/ground.

At any rate, if identical loads are present on each hot, there will be
no neutral current.

If the phase is 180 degres out of phase and you add them together you
have no potential!

Mark

...on the neutral.

No electricity in two wires at 180 degrees on phase have no potential,
ie no EMF, nada, nothing, they cancel each other out. Your 240 volts
is made up from two 120 lines that are the same phase. The electric
company does not run two generators 180 degrees out of phase at the
power plant. It is just to much of a pain in the ass to keep them
synchronized.

Mark

Bill wrote:
Mike Marlow wrote:
However, in
its favor, the LHITS model does provide an extra level of service
(should I be in sales?).

Categorically not!

Come on now! Fly-by-night Enterprises has entrusted me, to show you,
the handy-est and the dandy-est tool you have ever seen. And don't
you wanna see how it works??? arms outstretched You get out the
patented pan, and you place the fish between the patented pans, and
you get out the tool which is not a slicer, it's not a dicer--it's
not a chopper-in-a-hopper...And what, dare you ask, could it possibly
be??? ...
I actually worked retail for a few years in a big outdoor store. It
was okay at the time.


But - you never said what "it" is...

--

-Mike-

On Wed, 08 Dec 2010 20:12:31 -0500, Ecnerwal
wrote:

In article ,
Larry Jaques wrote:

On Wed, 08 Dec 2010 14:39:26 -0800, Mike M
wrote:
(B) Disconnecting Means. Each multiwire branch circuit
shall be provided with a means that will simultaneously
disconnect all ungrounded conductors at the point where
the branch circuit originates.

Mike, can you point out the particular text in that extract which
states the demand to tie two 120v breakers together when supplying
120v equipment?

I'm not mike, but that's what it says right there. "simultaneously
disconnect" is equivalent to, but more general than,"tied." Obviously
it's been edited over time (normal for code), since otherwise item C and
its exception #2 would not be relevant, having been required in item B...

I believe it talked about 240v and 3-phase and split-receptacles, but
not what we were discussing. That's why I brought it up. I wonder if
he'll answer.


Personal bias - just use a 240V breaker when you are contemplating
"tieing two together".

I can't imagine anyone wanting to tie two lighting circuits together.
If a ballast shorted, all the lights in the shop would be dead at
once...while the saw blades/router bits/planer blades were still
spinning.

--
Invest in America: Buy a CONgresscritter today!

On Wed, 08 Dec 2010 07:24:17 -0700, Doug Winterburn
wrote:

On 12/08/2010 06:32 AM, Markem wrote:
On Tue, 07 Dec 2010 21:06:47 -0700, Doug Winterburn
wrote:

OK, the two hots are 180 degrees out of phase with respect to the
center-tap/neutral/ground.

At any rate, if identical loads are present on each hot, there will be
no neutral current.

If the phase is 180 degres out of phase and you add them together you
have no potential!

Mark

Try this:

http://en.wikipedia.org/wiki/Split-phase_electric_power

And the neutral floats. Not all US power systems though. My coop is
one of them, only two hot wires up on the pole. And not stinking
breakers, good old fuses.

Mark

Bill wrote:
Mike Marlow wrote:

So... now that you're thinking about using conduit - go out and buy
yourself a 1/2" EMT bender.

Previous poster advised 3/4". I need to pull 8 #12 wires through. Which
size do you recommend?

Bill

Hot Dog Bill!!! Another book to buy. Now that you're going to venture into
the world of conduit, go to Home Depot (electrical department) and buy the
Ugly Book - or something like that. It's full of tables, and stuff that
you'll just love. And... it will answer this question.

--

-Mike-

In article , Bill
wrote:
Please see if my math makes sense:

Amps/fixture = (32w + 32w)/120v .6.

So a 15 Amp circuit(derated 80% to 12) with 14ga wire may support
at least 12/.6 = 20 fixtures.

Should I be considering a "ballast surge" or anything like that (like
they have when an electric motor is first started)?

Bill

Well, I looked at some actual 120V input numbers for a "high ballast
factor" (more light out, more current in than "standard" or "low"
ballast factor) 2-lamp F32T8 ballast, and got 18 fixtures (0.64 amps)
for 12 amps (15 derated 80% for continuous use) - actually 18.75, but
there are no 3/4 fixtures on the menu.

Starting surge, if any, won't be enough to matter - that's NOT
continuous for one thing, and a 15 amp breaker will happily supply 30
amps for a longer period that you might expect (far longer than any
start-up surge in your ballasts. Wire sizes and code are quite familiar
with those details and take them into account.) A modern ballast
probably has little, if any, anyway.

Now, that is an energy-star efficient ballast which also has good power
factor - and the "standard" ballast factor version (0.46 amps) will run
26 ballasts on 12 amps. A different brand of standard ballast (0.49
amps) will run 24 ballasts. I'd prefer a real example for a terrible
ballast, but the cheap shop lights are a few miles from the computer -
IIRC some of them might be as much as 0.75 amps for a two tube fixture -
they don't actually use more power, but the power factor is terrible, so
they draw a lot more amps.

As such, I think you are fairly safe running your 15-16 fixtures on a 15
amp circuit - but as always, check the actual numbers before you spend
your money on fixtures. The ones with terrible power factors draw a lot
more current, even if they are running the same wattage.

--
Cats, coffee, chocolate...vices to live by

Ecnerwal wrote:
In article , Bill
wrote:

Mike Marlow wrote:

So... now that you're thinking about using conduit - go out and buy
yourself a 1/2" EMT bender.

Previous poster advised 3/4". I need to pull 8 #12 wires through.
Which size do you recommend?

Bill

Reiterating what I said in another post, I find your defaulting to
12Ga makes no sense when I think about what you are running on it
(amperage loads). As for conduit size, it's always easier to use
larger conduit, and costs little more for the extra ease and space.
1/2" is technically fine for 8 12Ga THHN - that does not mean it will
be a pleasant pull.

http://www.electrician2.com/calculat...alculator.html

I see no reason you can't run a 15 amp breaker (or breakers) and 14 ga
wire for the number of lights you are talking about (and I'm also a
bit confused about where you think you need 8 wires in one conduit
for your layout.)

I cannot take any exception to the above post - it is technically correct.
I'll only add that I don't carry rolls and rolls of wire, so I'll simply
pull 12ga for everything. For me - it's easier and more cost effective.
For a commercial electricain who lives and dies by this work - maybe not so
much. The other benefit - many if not most of my work is subject to
"improvements" down the road - and not by me. Anticipating that home
owners, or church members or any other likely candidate will almost
assuredly have their fingers in this at some point, I do a couple of things.
I lightly load circuits, and I wire with all 12ga. Yeah - I know it does
not cover every conceivable in-house add-on, but I've at least done my best
to accommodate that eventual "oh - I'll just tie into this circuit" by the
well-intendeds of the world. Sure - it is overkill. Sorry about that. I
wasted $1.39.

--

-Mike-

Nova wrote:


It would take me until mid-March to get one "box offset" done right. I
suck at bending conduit.

Nah - ya just keep bending the **** until it fits right. If it don't - ya
just get some more conduit...

--

-Mike-

Ecnerwal wrote:
In article om,
Nova wrote:

It would take me until mid-March to get one "box offset" done right.
I suck at bending conduit.

For you (and others) they can be purchased as a complete die casting
with an EMT socket on one end and threads for the box on the other. Or
threads on both.

Cheater...

--

-Mike-

Larry Jaques wrote:
On Wed, 08 Dec 2010 19:43:32 -0500, Bill wrote:

Mike Marlow wrote:
I bet you find
you've been making a mountain out of a mole hill here.

I hope so. But, from my vantage point, the part about how to wire a
bunch of fixtures in parallel, properly, was a decent-sized mole
hill!

Didn't you just wire outlets in parallel before putting in your
drywall? It's exactly the same but there is a switch between the
panel and fixtures.


Ding, Ding, Ding! Give Larry the prize. (what the hell is the prize
today?). Unless of course Bill wired them in series...

--

-Mike-

In article ,
"Mike Marlow" wrote:
I cannot take any exception to the above post - it is technically correct.
I'll only add that I don't carry rolls and rolls of wire, so I'll simply
pull 12ga for everything. For me - it's easier and more cost effective.
For a commercial electricain who lives and dies by this work - maybe not so
much. The other benefit - many if not most of my work is subject to
"improvements" down the road - and not by me. Anticipating that home
owners, or church members or any other likely candidate will almost
assuredly have their fingers in this at some point, I do a couple of things.
I lightly load circuits, and I wire with all 12ga. Yeah - I know it does
not cover every conceivable in-house add-on, but I've at least done my best
to accommodate that eventual "oh - I'll just tie into this circuit" by the
well-intendeds of the world. Sure - it is overkill. Sorry about that. I
wasted $1.39.

For a 9'3" run. It's about a 15 cent per foot differential if buying 500
foot rolls and running 3 wires.

Depending what you have on hand and what you have to buy, the economics
work out various ways. If the outlets are already wired, you ONLY need
to wire the lights, and you're looking at buying black/white/green (or
bare) in 500 foot rolls it's $120 to get three rolls of #14 and $195 to
get three rolls of #12.

If you need the #12 anyway for outlets, and 500 feet is more than
enough, the #12 can actually be less money overall if it means not
buying any #14 - more or less your position.

If you are buying it by the foot (the economics of that are rarely good,
but should be checked at local suppliers especially if the total footage
is short) the #14 will definitely be cheaper.

On the third hand, 250 feet of 14-2 NM will only set you back $48.20
(all are HD's local prices, yours may be better or worse or better not
at HD.)

And, if you can find someone else's leftovers on craigslist (et al), it
might be a LOT cheaper if your job is not larger than their leftover
wire. If not wiring until March, that's a good opportunity to hunt for
someone that bought 3-4 rolls of THHN and ran out of project before they
ran out of wire - might try the wanted section to troll for that,
assuming you can filter the resultant spam. Otherwise just keep an eye
on it looking for THHN.

--
Cats, coffee, chocolate...vices to live by

On Wed, 08 Dec 2010 14:39:26 -0800, Mike M
wrote:

On Tue, 07 Dec 2010 20:17:50 -0800, Larry Jaques
wrote:

On Tue, 07 Dec 2010 13:16:11 -0500, wrote:

On Mon, 06 Dec 2010 23:02:40 -0500, Bill wrote:

Scott Lurndal wrote:
writes:

To avoid "cycling the breakers", Lew advised running 12-3 from two 20
Amp breakers (it would not have occurred to me to do that).

I'm not sure what this means, but if you're running two 120v circuits
using 12-3 from a pair of 20A breakers, make sure the breaker handles
are tied together such that both trip if either one trips.

scott

Because???

Because 1) - it is code.

Show me code in any country which demands tied circuit breaker handles
for 120v circuits. I double dog dare you!


2) if one circuit trips and you assume the wire is "dead" you
could be - the black could be dead, and the red live, and a lifted
neutral (which is common to both) would be LIVE.

We're talking 120v here, not 240, clare. With 240v, both phases are
going to the same box. Here, there are separate circuits and boxes
with a single phase going to each.


It's not phases, but I get your point. I was ASSuming you were going
to pull a 12/3 to the switch box, split the neutral and tie the black
to one switch and the red to the other,, then run either 12/2 or
separate wires in conduit to each of the separate light strings. If
running NMD, it has often even been done with 12/3 up to the chase
(lamp trough, or whatever you want to call it) where alternate lights
in a string are switched.


210.4 Multiwire Branch Circuits.
(A) General. Branch circuits recognized by this article
shall be permitted as multiwire circuits. A multiwire circuit
shall be permitted to be considered as multiple circuits. All
conductors of a multiwire branch circuit shall originate
from the same panelboard or similar distribution equipment.
FPN: A 3-phase, 4-wire, wye-connected power system
used to supply power to nonlinear loads may necessitate
that the power system design allow for the possibility of
high harmonic currents on the neutral conductor.
(B) Disconnecting Means. Each multiwire branch circuit
shall be provided with a means that will simultaneously
disconnect all ungrounded conductors at the point where
the branch circuit originates.
(C) Line-to-Neutral Loads. Multiwire branch circuits
shall supply only line-to-neutral loads.
Exception No. 1: A multiwire branch circuit that supplies
only one utilization equipment.
Exception No. 2: Where all ungrounded conductors of the
multiwire branch circuit are opened simultaneously by the
branch-circuit overcurrent device.
FPN: See 300.13(B) for continuity of grounded conductor
on multiwire circuits.
(D) Grouping. The ungrounded and grounded conductors
of each multiwire branch circuit shall be grouped by wire
ties or similar means in at least one location within the
panelboard or other point of origination.
Exception: The requirement for grouping shall not apply if
the circuit enters from a cable or raceway unique to the
circuit that makes the grouping obvious.
ARTICLE 210€”BRANCH CIRCUITS 210.4
2008 Edition NATIONAL ELECTRICAL CODE

Mike M

On Wed, 08 Dec 2010 15:13:53 -0800, Larry Jaques
wrote:

On Wed, 08 Dec 2010 14:39:26 -0800, Mike M
wrote:

On Tue, 07 Dec 2010 20:17:50 -0800, Larry Jaques
wrote:

On Tue, 07 Dec 2010 13:16:11 -0500, wrote:

On Mon, 06 Dec 2010 23:02:40 -0500, Bill wrote:

Scott Lurndal wrote:
writes:

To avoid "cycling the breakers", Lew advised running 12-3 from two 20
Amp breakers (it would not have occurred to me to do that).

I'm not sure what this means, but if you're running two 120v circuits
using 12-3 from a pair of 20A breakers, make sure the breaker handles
are tied together such that both trip if either one trips.

scott

Because???

Because 1) - it is code.

Show me code in any country which demands tied circuit breaker handles
for 120v circuits. I double dog dare you!


2) if one circuit trips and you assume the wire is "dead" you
could be - the black could be dead, and the red live, and a lifted
neutral (which is common to both) would be LIVE.

We're talking 120v here, not 240, clare. With 240v, both phases are
going to the same box. Here, there are separate circuits and boxes
with a single phase going to each.



210.4 Multiwire Branch Circuits.
(A) General. Branch circuits recognized by this article
shall be permitted as multiwire circuits. A multiwire circuit
shall be permitted to be considered as multiple circuits. All
conductors of a multiwire branch circuit shall originate
from the same panelboard or similar distribution equipment.
FPN: A 3-phase, 4-wire, wye-connected power system
used to supply power to nonlinear loads may necessitate
that the power system design allow for the possibility of
high harmonic currents on the neutral conductor.
(B) Disconnecting Means. Each multiwire branch circuit
shall be provided with a means that will simultaneously
disconnect all ungrounded conductors at the point where
the branch circuit originates.
(C) Line-to-Neutral Loads. Multiwire branch circuits
shall supply only line-to-neutral loads.
Exception No. 1: A multiwire branch circuit that supplies
only one utilization equipment.
Exception No. 2: Where all ungrounded conductors of the
multiwire branch circuit are opened simultaneously by the
branch-circuit overcurrent device.
FPN: See 300.13(B) for continuity of grounded conductor
on multiwire circuits.
(D) Grouping. The ungrounded and grounded conductors
of each multiwire branch circuit shall be grouped by wire
ties or similar means in at least one location within the
panelboard or other point of origination.
Exception: The requirement for grouping shall not apply if
the circuit enters from a cable or raceway unique to the
circuit that makes the grouping obvious.
ARTICLE 210€”BRANCH CIRCUITS 210.4
2008 Edition NATIONAL ELECTRICAL CODE

Mike, can you point out the particular text in that extract which
states the demand to tie two 120v breakers together when supplying
120v equipment?


B) Disconnecting Means. Each multiwire branch circuit
shall be provided with a means that will simultaneously
disconnect all ungrounded conductors at the point where
the branch circuit originates.

Larry Jaques wrote:
On Wed, 08 Dec 2010 19:43:32 -0500, wrote:

Mike Marlow wrote:
I bet you find
you've been making a mountain out of a mole hill here.

I hope so. But, from my vantage point, the part about how to wire a
bunch of fixtures in parallel, properly, was a decent-sized mole hill!

Didn't you just wire outlets in parallel before putting in your
drywall? It's exactly the same but there is a switch between the
panel and fixtures.

I haven't put any of the outlets in the boxes yet as I'm waiting until I
paint, but YES, you are absolutely right! I stopped to dwell on this
for longer than it shows here. I am very glad that you brought it up! I
will share with you that, while I understood what I needed to do
beforehand, I was not thinking in those terms as I nailed electrical
boxes up in rows and spanned lengths of romex between them. I'll be
using a pigtails instead of the (removable) connectors on my duplex
outlets to add additional devices...( big Duh).

As far as the light fixtures, I was thinking about using a good bit more
wire than I need to (with unnecessary trips back to the pull box at the
end of each row...). DUH, DUH, DUH!!!

Say I wanted to run 2 circuits through the conduit, to steer clear of
"edison's problem". Would the NEC advise using a wire of a particular
color for the second common, or would it insist on separate conduits for
each circuit (probably...). The The idea of having 2 white wires
running through the conduit is clearly ridiculous!

Thanks for helping to teach me a good lesson today!
By no means mole hill!

Bill

Ecnerwal,

Your post was interesting and insightful. Thanks!

Bill

Ecnerwal wrote:

Well, I looked at some actual 120V input numbers for a "high ballast
factor" (more light out, more current in than "standard" or "low"
ballast factor) 2-lamp F32T8 ballast, and got 18 fixtures (0.64 amps)
for 12 amps (15 derated 80% for continuous use) - actually 18.75, but
there are no 3/4 fixtures on the menu.

Starting surge, if any, won't be enough to matter - that's NOT
continuous for one thing, and a 15 amp breaker will happily supply 30
amps for a longer period that you might expect (far longer than any
start-up surge in your ballasts. Wire sizes and code are quite familiar
with those details and take them into account.) A modern ballast
probably has little, if any, anyway.

Now, that is an energy-star efficient ballast which also has good power
factor - and the "standard" ballast factor version (0.46 amps) will run
26 ballasts on 12 amps. A different brand of standard ballast (0.49
amps) will run 24 ballasts. I'd prefer a real example for a terrible
ballast, but the cheap shop lights are a few miles from the computer -
IIRC some of them might be as much as 0.75 amps for a two tube fixture -
they don't actually use more power, but the power factor is terrible, so
they draw a lot more amps.

As such, I think you are fairly safe running your 15-16 fixtures on a 15
amp circuit - but as always, check the actual numbers before you spend
your money on fixtures. The ones with terrible power factors draw a lot
more current, even if they are running the same wattage.

In article , Bill
wrote:
Say I wanted to run 2 circuits through the conduit, to steer clear of
"edison's problem". Would the NEC advise using a wire of a particular
color for the second common, or would it insist on separate conduits for
each circuit (probably...). The The idea of having 2 white wires
running through the conduit is clearly ridiculous!

Various means work. They can be coded with colored tape, grouped to the
related hot conductor with a wire tie, labeled with actual readable
labels, etc. I don't know what, if anything, present code specifies for
that, but it would be absurdly limiting to only have one circuit in a
conduit (or raceway, if you want to get all code languange-y.)

If, say, wiring up two circuits with black, white and green/bare, you
could simply tag both ends of one circuit's 3 wires with blue (or pick
your favorite color) tape.

--
Cats, coffee, chocolate...vices to live by

On 12/9/2010 11:19 AM, Ecnerwal wrote:
In ,
wrote:
Say I wanted to run 2 circuits through the conduit, to steer clear of
"edison's problem". Would the NEC advise using a wire of a particular
color for the second common, or would it insist on separate conduits for
each circuit (probably...). The The idea of having 2 white wires
running through the conduit is clearly ridiculous!

Various means work. They can be coded with colored tape, grouped to the
related hot conductor with a wire tie, labeled with actual readable
labels, etc. I don't know what, if anything, present code specifies for
that, but it would be absurdly limiting to only have one circuit in a
conduit (or raceway, if you want to get all code languange-y.)

If, say, wiring up two circuits with black, white and green/bare, you
could simply tag both ends of one circuit's 3 wires with blue (or pick
your favorite color) tape.


Thank you. That works for me! There will be enough "blue tape" around to
eliminate any confusion.

With new 3/4" conduit around, it makes one start thinking about the
possibility for those ceiling outlets that seemed like such a stretch
before... They are just a new roll of colored tape away! : )

Bill

On 12/9/2010 12:31 PM, Bill wrote:

Thank you. That works for me! There will be enough "blue tape" around to
eliminate any confusion.

With new 3/4" conduit around, it makes one start thinking about the
possibility for those ceiling outlets that seemed like such a stretch
before... They are just a new roll of colored tape away! : )

Bill


Or even easier, just have them share a heavier circuit (which has
indirectly already been suggested). I'll have to sleep on it.

Bill

On Wed, 8 Dec 2010 21:35:38 -0500, "Mike Marlow"
wrote:

Bill wrote:
Mike Marlow wrote:

So... now that you're thinking about using conduit - go out and buy
yourself a 1/2" EMT bender.

Previous poster advised 3/4". I need to pull 8 #12 wires through. Which
size do you recommend?

Bill

Hot Dog Bill!!! Another book to buy. Now that you're going to venture into
the world of conduit, go to Home Depot (electrical department) and buy the
Ugly Book - or something like that. It's full of tables, and stuff that
you'll just love. And... it will answer this question.

_Ugly's Electrical Reference_ by George V. Hart

--
Invest in America: Buy a CONgresscritter today!

In article ,
Bill wrote:

On 12/9/2010 12:31 PM, Bill wrote:

Thank you. That works for me! There will be enough "blue tape" around to
eliminate any confusion.

With new 3/4" conduit around, it makes one start thinking about the
possibility for those ceiling outlets that seemed like such a stretch
before... They are just a new roll of colored tape away! : )

Or even easier, just have them share a heavier circuit (which has
indirectly already been suggested). I'll have to sleep on it.

The odds of having the lights go out increase dramatically as soon as
you do that. I don't think I've _ever_ had a ballast "short out and blow
a breaker" - they usually fail much less dramatically and the tubes
associated with them stop lighting up. Not that it could never happen,
just hasn't in 40+ years.

Start hanging power tools off the same circuit and things change. I
detest lights and outlets on the same circuits because I've lived too
many places with that setup and learned to hate the consequences.

--
Cats, coffee, chocolate...vices to live by

On 12/9/2010 1:45 PM, Ecnerwal wrote:
In ,
wrote:

On 12/9/2010 12:31 PM, Bill wrote:

Thank you. That works for me! There will be enough "blue tape" around to
eliminate any confusion.

With new 3/4" conduit around, it makes one start thinking about the
possibility for those ceiling outlets that seemed like such a stretch
before... They are just a new roll of colored tape away! : )

Or even easier, just have them share a heavier circuit (which has
indirectly already been suggested). I'll have to sleep on it.

The odds of having the lights go out increase dramatically as soon as
you do that. I don't think I've _ever_ had a ballast "short out and blow
a breaker" - they usually fail much less dramatically and the tubes
associated with them stop lighting up. Not that it could never happen,
just hasn't in 40+ years.

Start hanging power tools off the same circuit and things change. I
detest lights and outlets on the same circuits because I've lived too
many places with that setup and learned to hate the consequences.


Okay Ecnerwal, that makes good sense. Coming into this project with
little practical experience (as you may have been able to tell), my
unintentionally vague notions usually pick up some substance when I
share them here with some of the kind folks here who, like yourself,
know what the heck they're doing! In the process, the cost of
implementing my vague notions usually doubles or triples, at least!
But, besides learning a lot, I'm avoiding big design flaws that aren't
easily remedied, like the one you just pointed out. I'll will pick up
Ugly's guide (I was meaning to anyway), and start looking at some of the
numbers. I'm grateful for all of your help!

Bill

On Wed, 8 Dec 2010 21:49:08 -0500, "Mike Marlow"
wrote:

Larry Jaques wrote:
On Wed, 08 Dec 2010 19:43:32 -0500, Bill wrote:

Mike Marlow wrote:
I bet you find
you've been making a mountain out of a mole hill here.

I hope so. But, from my vantage point, the part about how to wire a
bunch of fixtures in parallel, properly, was a decent-sized mole
hill!

Didn't you just wire outlets in parallel before putting in your
drywall? It's exactly the same but there is a switch between the
panel and fixtures.


Ding, Ding, Ding! Give Larry the prize. (what the hell is the prize
today?).

Cherry Magazine's Miss December, I hope?


Unless of course Bill wired them in series...

Visions of magic smoke dance in my head...

--
Invest in America: Buy a CONgresscritter today!

On Thu, 09 Dec 2010 00:33:37 -0500, Bill wrote:

Larry Jaques wrote:
On Wed, 08 Dec 2010 19:43:32 -0500, wrote:

Mike Marlow wrote:
I bet you find
you've been making a mountain out of a mole hill here.

I hope so. But, from my vantage point, the part about how to wire a
bunch of fixtures in parallel, properly, was a decent-sized mole hill!

Didn't you just wire outlets in parallel before putting in your
drywall? It's exactly the same but there is a switch between the
panel and fixtures.

I haven't put any of the outlets in the boxes yet as I'm waiting until I

Uno mas tip: Don't ever use the stab-in connection on the back of the
outlet, always use the screws. Stab-ins are a fire waiting to happen.


paint, but YES, you are absolutely right! I stopped to dwell on this
for longer than it shows here. I am very glad that you brought it up! I
will share with you that, while I understood what I needed to do
beforehand, I was not thinking in those terms as I nailed electrical
boxes up in rows and spanned lengths of romex between them. I'll be
using a pigtails instead of the (removable) connectors on my duplex
outlets to add additional devices...( big Duh).

I have no idea what that last sentence means, nor why it's in a
lighting thread, but you said "duplex".

Haven't you gone back in, cut larger openings, and installed quad
boxes yet? It's only half an hour and a couple bucks difference per
outlet site, but the convenience is worth its weight in gold. If not,
you'll spend more money just tacking up a power strip and plugging it
into one of the duplex outlets for all the extras you _will_ want to
go to that particular area. This is especially true around
workbenches and assembly areas.

As far as the light fixtures, I was thinking about using a good bit more
wire than I need to (with unnecessary trips back to the pull box at the
end of each row...). DUH, DUH, DUH!!!

I haven't done this yet, but most of the fixtures have punchouts in
the ends so you can run conduit between them. You could make just 2
runs of romex (plus a jumper from row 1 to 3, for a 12-fixture/3-row
setup) down a single rafter "hole", then run short THNN lengths
between the fixtures. 100' of romex and 3 100' rolls of THNN would
probably do it.


Say I wanted to run 2 circuits through the conduit, to steer clear of
"edison's problem". Would the NEC advise using a wire of a particular
color for the second common, or would it insist on separate conduits for
each circuit (probably...). The The idea of having 2 white wires
running through the conduit is clearly ridiculous!

I believe red is used for a secondary hot, as in 240v runs.


Thanks for helping to teach me a good lesson today!
By no means mole hill!

Which one did I teach you? Oh, parallel. Got it. Jewelcome.

--
Invest in America: Buy a CONgresscritter today!

Bill wrote:
On 12/9/2010 11:19 AM, Ecnerwal wrote:
In ,
wrote:
Say I wanted to run 2 circuits through the conduit, to steer clear
of "edison's problem". Would the NEC advise using a wire of a
particular color for the second common, or would it insist on
separate conduits for each circuit (probably...). The The idea of
having 2 white wires running through the conduit is clearly
ridiculous!

Various means work. They can be coded with colored tape, grouped to
the related hot conductor with a wire tie, labeled with actual
readable labels, etc. I don't know what, if anything, present code
specifies for that, but it would be absurdly limiting to only have
one circuit in a conduit (or raceway, if you want to get all code
languange-y.) If, say, wiring up two circuits with black, white and
green/bare, you
could simply tag both ends of one circuit's 3 wires with blue (or
pick your favorite color) tape.


Thank you. That works for me! There will be enough "blue tape" around
to eliminate any confusion.

With new 3/4" conduit around, it makes one start thinking about the
possibility for those ceiling outlets that seemed like such a stretch
before... They are just a new roll of colored tape away! : )


It will pay to read more before you get too carried away Bill. For one -
you don't need a separate green (ground) for each circuit in a conduit when
wiring with THHN.

--

-Mike-

Larry Jaques wrote:

Haven't you gone back in, cut larger openings, and installed quad
boxes yet?

Yep, I'm going to have quite a few outlets: 4 quad, 2 duplex, and 3 220s.


I haven't done this yet, but most of the fixtures have punchouts in
the ends so you can run conduit between them. You could make just 2
runs of romex (plus a jumper from row 1 to 3, for a 12-fixture/3-row
setup) down a single rafter "hole", then run short THNN lengths
between the fixtures. 100' of romex and 3 100' rolls of THNN would
probably do it.

Took me a few minutes to figure that one out. The two runs are for 2
different (light) switches, right? Dern interesting design.. Saves not
only wire, but conduit, and junction boxes too I think!

On the other hand, the design may make trouble-shooting more difficult
than if there were a pull box at end of each luminaire run/row.
Do you agree?

Bill

"Bill" wrote:

I haven't done this yet, but most of the fixtures have punchouts in
the ends so you can run conduit between them. You could make just
2
runs of romex (plus a jumper from row 1 to 3, for a
12-fixture/3-row
setup) down a single rafter "hole", then run short THNN lengths
between the fixtures. 100' of romex and 3 100' rolls of THNN would
probably do it.

Took me a few minutes to figure that one out. The two runs are for 2
different (light) switches, right? Dern interesting design.. Saves
not only wire, but conduit, and junction boxes too I think!
-----------
Buy them books, they eat the friggin covers.

You may have read my design post, but you obviously didn't understand
it.

Lew

On Wed, 08 Dec 2010 20:22:31 -0500, Nova wrote:

Mike Marlow wrote:


Oh hell - we all learn from each other's posts. The true beauty (and the
original intent...) of newsgroups. Wiring in conduit is nothing major.
Don't read into what you read too much. It's really straightforward stuff.
So... now that you're thinking about using conduit - go out and buy yourself
a 1/2" EMT bender. While away the hours between now and mid-March, studying
how to bend EMT, practicing it, learning how to quickly get rid of those
nasty pretzel bends that you'll be guaranteed to make in the beginning, and
by mid-March, you'll be up on your ladder hanging conduit. You'll love it -
it has such an industrial look. Really impresses the chicks...


It would take me until mid-March to get one "box offset" done right. I
suck at bending conduit.

They actually make an offset bender. Most of the work we did was up
in scissor lifts where it was hard to bend. So we would pop the end
in the offset bender pull the lever and perfect. But its not that
hard if you have the shrinkage formula and use the conduit seem for
alingnment.

Mike M

On Wed, 08 Dec 2010 20:50:41 -0500, Bill wrote:

Ecnerwal wrote:
- you'll need
a lot of fixtures to warrant #12 and a 20 amp 240V circuit, .vs. #14 and
a 15 amp circuit.) At half an amp or so per 4-lamp F32T8 ballast at
240V, 24 ballasts (circuit derated to 80% for being on a long time) and
96 tubes (384 feet, if you like) on one circuit and 14 ga wire. For that
matter I'm danged if I know why folks are talking 12Ga wire on a
lighting-only circuit that might, at most, be 16 two-tube fixtures, and
probably won't even be that. Unless the ballasts are terrible (awful
power factor, inefficient) that should normally be well within the
capacity of a single 15 amp 120V circuit - and if being split in twain
so that they don't all go out at once (which, if it is really a lighting
only circuit, is far from likely in my experience, but I respect it as a
design goal) it's even more blatantly inside the reach of a 15 amp 120V
circuit to run half or 2/3's of that load on 14Ga wire.

I do overkill, but I try to avoid _stupid_ levels of overkill when it
costs me serious money. 20 amp breakers and/or 12ga wire to feed 2-lamp
4-foot fixtures in this quantity seems rather stupid, even for me - and
I have most of 1000 feet of 12-2NM I happened to buy back when it cost
$118.

Please see if my math makes sense:

Amps/fixture = (32w + 32w)/120v .6.

So a 15 Amp circuit(derated 80% to 12) with 14ga wire may support
at least 12/.6 = 20 fixtures.

Should I be considering a "ballast surge" or anything like that (like
they have when an electric motor is first started)?

Bill


Don't get to concerned about the THD unless your doing a large
structure with transformers, or your planning on turning your shop
into a server farm. I would be more concerned with the Ballast factor
which will give you a better idea of the performance you can expect.
Ballast factor can range from about .78 to 1.19. I'd be sure I got
something in the range of at least .88. If your conserned about the
ballasts just install glr fuses in each fixture. How ever many
fixtures you put on a circuit keep it to 12 amps max for 15 amp and 16
amps for a 20 amp circuit. Can't use a larger circuit with
fluorescent. If you load the circuits lighter you can add task
lighting later to existing circuits.

Mike M

On Wed, 08 Dec 2010 15:13:53 -0800, Larry Jaques
wrote:

On Wed, 08 Dec 2010 14:39:26 -0800, Mike M
wrote:

On Tue, 07 Dec 2010 20:17:50 -0800, Larry Jaques
wrote:

On Tue, 07 Dec 2010 13:16:11 -0500, wrote:

On Mon, 06 Dec 2010 23:02:40 -0500, Bill wrote:

Scott Lurndal wrote:
writes:

To avoid "cycling the breakers", Lew advised running 12-3 from two 20
Amp breakers (it would not have occurred to me to do that).

I'm not sure what this means, but if you're running two 120v circuits
using 12-3 from a pair of 20A breakers, make sure the breaker handles
are tied together such that both trip if either one trips.

scott

Because???

Because 1) - it is code.

Show me code in any country which demands tied circuit breaker handles
for 120v circuits. I double dog dare you!


2) if one circuit trips and you assume the wire is "dead" you
could be - the black could be dead, and the red live, and a lifted
neutral (which is common to both) would be LIVE.

We're talking 120v here, not 240, clare. With 240v, both phases are
going to the same box. Here, there are separate circuits and boxes
with a single phase going to each.



210.4 Multiwire Branch Circuits.
(A) General. Branch circuits recognized by this article
shall be permitted as multiwire circuits. A multiwire circuit
shall be permitted to be considered as multiple circuits. All
conductors of a multiwire branch circuit shall originate
from the same panelboard or similar distribution equipment.
FPN: A 3-phase, 4-wire, wye-connected power system
used to supply power to nonlinear loads may necessitate
that the power system design allow for the possibility of
high harmonic currents on the neutral conductor.
(B) Disconnecting Means. Each multiwire branch circuit
shall be provided with a means that will simultaneously
disconnect all ungrounded conductors at the point where
the branch circuit originates.

This is it right there in part B. It wasn't alway that way we used to
always run full boats for lighting with all 3 phases and one nuetral.
Be it ties or a single 2 Or 3 pole breaker

Mike M

snipped

Mike, can you point out the particular text in that extract which
states the demand to tie two 120v breakers together when supplying
120v equipment?

Lew Hodgett wrote:

-----------
Buy them books, they eat the friggin covers.

You may have read my design post, but you obviously didn't understand
it.

Lew


I think/thought I did. I like your design! Isn't this it:

||
||
||
JB====L1====L2====L1====L2
||
||
||
JB====L2====L1====L2====L1
||
||
||
JB====L1====L2====L1====L2
||
||
||
JB====L2====L1====L2====L1

I think I basically like it, especially the way the circuits split at
the junction boxes (in a way that I think would be easy to
troubleshoot). What do you think I am missing?

Bill

On Thu, 09 Dec 2010 18:20:31 -0500, Bill wrote:

Larry Jaques wrote:

Haven't you gone back in, cut larger openings, and installed quad
boxes yet?

Yep, I'm going to have quite a few outlets: 4 quad, 2 duplex, and 3 220s.


I haven't done this yet, but most of the fixtures have punchouts in
the ends so you can run conduit between them. You could make just 2
runs of romex (plus a jumper from row 1 to 3, for a 12-fixture/3-row
setup) down a single rafter "hole", then run short THNN lengths
between the fixtures. 100' of romex and 3 100' rolls of THNN would
probably do it.

Took me a few minutes to figure that one out. The two runs are for 2
different (light) switches, right? Dern interesting design.. Saves not
only wire, but conduit, and junction boxes too I think!

On the other hand, the design may make trouble-shooting more difficult
than if there were a pull box at end of each luminaire run/row.
Do you agree?

I was thinking that you could run romex down from the top into the
hollow between joists, then out through a small hole in the pristine
ceiling drywall, into the starter fixture, then thnn to the next 3 in
the row.

Romex vertical from the panel, left over one cavity down to the two
switches, then back up over the door to the left, up to the running
board (IIRC you called it that) then down into the first or second
joist cavity and over to the hook up to first and third rows.
(This from memory of your shop layout.)

The second switch romex output would go to the center row, fixtures
connected by pvc conduit (cheaper/easier.)

Email your Sketchup file to me, will ya? (remove "invalid" to send)

--
Invest in America: Buy a CONgresscritter today!

Mike M wrote:

Ballast factor can range from about .78 to 1.19. I'd be sure I got
something in the range of at least .88. If your conserned about the
ballasts just install glr fuses in each fixture.

I wasn't too concerned. Should I be? : )
I'm going to browse over to Luthonia.com and see if they give the
"ballast factor" in the specifications.


How ever many
fixtures you put on a circuit keep it to 12 amps max for 15 amp and 16
amps for a 20 amp circuit. Can't use a larger circuit with
fluorescent. If you load the circuits lighter you can add task
lighting later to existing circuits.

Mike M



Yep. That's a good point. I mentioned before I had two lights that were
already powered by a separate sub-panel. I think I'll probably replace
and reconfigure those, using their existing wiring, so that they blend
in with the new flock of lights. I'm not ready to consider the
implications of that decision regarding my conduit yet..hopefully none.

Bill

In article -
september.org, lid says...

In article ,
Bill wrote:

On 12/9/2010 12:31 PM, Bill wrote:

Thank you. That works for me! There will be enough "blue tape" around to
eliminate any confusion.

With new 3/4" conduit around, it makes one start thinking about the
possibility for those ceiling outlets that seemed like such a stretch
before... They are just a new roll of colored tape away! : )

Or even easier, just have them share a heavier circuit (which has
indirectly already been suggested). I'll have to sleep on it.

The odds of having the lights go out increase dramatically as soon as
you do that. I don't think I've _ever_ had a ballast "short out and blow
a breaker" - they usually fail much less dramatically and the tubes
associated with them stop lighting up. Not that it could never happen,
just hasn't in 40+ years.

Start hanging power tools off the same circuit and things change. I
detest lights and outlets on the same circuits because I've lived too
many places with that setup and learned to hate the consequences.

Just a comment but some receptacles on the lighting circuit can be handy
for adding supplemental lighting. One switch still controls everything.
But they should have non-switched receptacles right next to them on a
different circuit, and be _marked_ as to which is which--one way to
"mark" them is to use different colors for the switched and non-switched
and match the color of the receptacle and switch, i.e. brown switch and
receptacle for the switched and ivory receptacle for the non-switched.

Mike Marlow wrote:
Bill wrote:
On 12/9/2010 11:19 AM, Ecnerwal wrote:
In ,
wrote:
Say I wanted to run 2 circuits through the conduit, to steer clear
of "edison's problem". Would the NEC advise using a wire of a
particular color for the second common, or would it insist on
separate conduits for each circuit (probably...). The The idea of
having 2 white wires running through the conduit is clearly
ridiculous!

Various means work. They can be coded with colored tape, grouped to
the related hot conductor with a wire tie, labeled with actual
readable labels, etc. I don't know what, if anything, present code
specifies for that, but it would be absurdly limiting to only have
one circuit in a conduit (or raceway, if you want to get all code
languange-y.) If, say, wiring up two circuits with black, white and
green/bare, you
could simply tag both ends of one circuit's 3 wires with blue (or
pick your favorite color) tape.


Thank you. That works for me! There will be enough "blue tape" around
to eliminate any confusion.

With new 3/4" conduit around, it makes one start thinking about the
possibility for those ceiling outlets that seemed like such a stretch
before... They are just a new roll of colored tape away! : )


It will pay to read more before you get too carried away Bill. For one -
you don't need a separate green (ground) for each circuit in a conduit when
wiring with THHN.


I didn't think so, but I inferred maybe one did from the post above. I
believe you. I haven't bought any wire, conduit or fixtures yet.

Bill

J. Clarke wrote:
In -
september.org, lid says...

In ,
wrote:

On 12/9/2010 12:31 PM, Bill wrote:

Thank you. That works for me! There will be enough "blue tape" around to
eliminate any confusion.

With new 3/4" conduit around, it makes one start thinking about the
possibility for those ceiling outlets that seemed like such a stretch
before... They are just a new roll of colored tape away! : )

Or even easier, just have them share a heavier circuit (which has
indirectly already been suggested). I'll have to sleep on it.

The odds of having the lights go out increase dramatically as soon as
you do that. I don't think I've _ever_ had a ballast "short out and blow
a breaker" - they usually fail much less dramatically and the tubes
associated with them stop lighting up. Not that it could never happen,
just hasn't in 40+ years.

Start hanging power tools off the same circuit and things change. I
detest lights and outlets on the same circuits because I've lived too
many places with that setup and learned to hate the consequences.

Just a comment but some receptacles on the lighting circuit can be handy
for adding supplemental lighting. One switch still controls everything.
But they should have non-switched receptacles right next to them on a
different circuit, and be _marked_ as to which is which--one way to
"mark" them is to use different colors for the switched and non-switched
and match the color of the receptacle and switch, i.e. brown switch and
receptacle for the switched and ivory receptacle for the non-switched.


Yeah, it's more fun than home decorating too! : )

Bill

Lew Hodgett wrote:


Trying to add additional circuits to the lighting systems is at best,
a bad wet dream.


Bad wet dream? Is that possible?

--

-Mike-