Shop electrical safety designs

Sounds like a lot of locks, when the best solution might be a lock on the
garage/shop door. Kids don't need to be playing unsupervised in a garage
even if it only houses the family car.

--
********
Bill Pounds
http://www.billpounds.com


"Brett A. Thomas" <[email protected]> wrote in message
news:[email protected]...
> All,
>
> Spent some time trolling the archives and Google, and couldn't really
> find what I was looking for. I suspect in part it's because I'm
> suffering from a Language Gap - there's a specific term for what I'm
> looking for, and I don't know what it is.
>
> So, I apologize in advance if this has been talked to death before, but
> I can't find it, if it is.
>
> First of all, my knee has recovered enough from surgery in the past week
> that I've been spending my free time in the new shop (18' 6" x 19' fully
> detached garage) emptying all the boxes that don't belong there,
> emptying the boxes that do belong there into the hideous cabinetry out
> there, running boxes to recycling, giving things to Goodwill, etc. Very
> exciting! I expect to be able to set the tablesaw back up by this
> weekend! February of last year was the last time I made sawdust.
>
> The walls and ceiling in the shop are exposed studs (16" centers) right
> now. I'm planning on putting drywall up on the ceiling and plywood on
> the walls. But that's not what I want to talk about (THAT is easy to
> find in the archives) - before I can do that, I have to get some wiring
> done. To get the wiring done, I have to make some key decisions.
>
> I'm a bit of a safety freak, and I have two small children (4 & 2).
> Short term I want to keep them out of the shop entirely without
> supervision, and the lock on the garage door will do well with that.
> Long term, I want to let them in the shop, but not let them do anything
> really dangerous without supervision (i.e., anything involving power
> tools). I'm also interested in emergency power cutoffs, mostly for my
> own use. Right now the garage is fed by a 240v 40 amp circuit that
> terminates in a sub panel in the garage. I recognize I may need more in
> the future, but it's enough for now.
>
> Without any thought whatsoever to the practicality or cost, the two big
> things I want are:
>
> A lockout box. I want to be able to leave lights and battery chargers
> on, but throw a switch, put a lock on it, and have no power tools operate.
>
> Several Big Red Buttons. I want to be able to hit a quick disconnect
> from one of several places in the shop, and have it kill the power to
> all the power tools (but not the lights or the battery chargers). Part
> of my problem is that I do not know what the industry Term of Art is for
> these buttons.
>
> Of course, we don't live in a world where practicality and cost aren't
> concerns, so if any requirement I list above is too much work or too
> much expense, I'm willing to rethink. If it's gonna cost me $2000, I
> can lose the emergency cutoffs and just put a lock on the subpanel I
> have and be done with it.
>
> So, here are my questions, and thanks in advance for anyone with the
> knowledge to answer, the inclination to help and the patience to read
> through my long-winded explanation:
>
> 1) What are Big Red Buttons called?
>
> 2) How do they work? Can I wire three circuits through one without
> needing a second subpanel?
>
> 3) What are the lockout box things called? Googling for "lockout box"
> gives me a bunch of storage boxes to store my lockout/tagout keys in. I
> think maybe a "safety switch" is what I want, something like this:
>
http://www.builderdepot.com/browse.ihtml?pid=145815&step=5&prodstoreid=2245
>
> 4) How do *they* work? Can I wire three circuits through one without
> needing a second subpanel?
>
> 5) If you held a gun to my head and said "Do it right now with what you
> know," I'd drop the emergency cutoff switches for now, install a new
> subpanel on a 30A breaker, and put a "safety switch" between the two of
> them. Is this, in fact, the best plan, or am I artificially limiting
> myself by my lack of knowledge?
>
> 6) Stupid question - I have this kooky idea to hook up a 50 ampish
> inline AC ammeter prior to the first subpanel. Is this stupid, or just
> geeky? I think it'd be pretty cool to always know how much juice I'm
> pulling.
>
> Thanks in advance...
>
> -BAT

"Brett A. Thomas" <[email protected]> wrote in message
news:[email protected]...
> Well, in the short term that's the plan - when they're this age, they
> never need to be out there.
>
> I know when I was, say 12, I spent a lot of time relatively unsupervised
> in the garage. I don't think they should have to get me to get a
> (neander) saw. My *hope* is that, when they're that age, I won't have
> to worry about them around power tools, either - I know when I was 12
> you couldn't've paid me enough to turn on my Grandfather's radial arm
> saw, I thought it was terrifying (even though I'd worked on it with
> him). But we won't know for sure until we get there, and there are
> always kids' friends who may be over and less intelligent than my own
> genius progeny ;). Whatever the exact age, I expect that there will be
> a point when I'm willing to trust them to use neander tools but not
> power tools.
>
> -BAT


Yea, I know it gets harder, not easier when they get older. I remember my
own youth. Our garage didn't even have a door for some of my teen years,
and my dad was an HVAC and steam fitting contractor so we had lots of power
stuff around. Not much woodworking though we did have a radial arm saw. I
shudder when now when I think of the stuff I did with that, and no
instruction from dear old dad at all. Just wasn't his style to worry about
the kids doing dumb stuff.

In addition to the RAS, I can recall:
-Playing with gasoline on the BBQ and setting my entire shirt sleeve on
fire - no burns, just singed hair.
-Putting power caps from the stud gun in a vice and firing them with a
hammer - no injury
-Welding stuff - might have been bad on my eyes, they aren't too good today
-Hooking the welder into the edison power drop above the rain hood with
alligator clamps - blew the fuses on a pole somewhere and shut down the
neighborhood power - I was smart enough to hide the evidence before edison
showed up to repair.
-Shot my brother in the chest from 50 feet with an arrow - lucky for us both
it was the blunt practice points. Actually, luckier for him than me. Hit
him dead center too.
-Shot the cat in the head with the same bow - but we all did that right?

Most of this was around JHS age. I'm amazed that bro and I survived without
any serious injury whatsoever. I do know that I learned a hell of a lot
about building things and making stuff work. I also learned to keep the
garage door locked whenever I was away.

Good luck with those yunguns.
--
Bill Pounds
http://www.billpounds.com/woodshop

Brett A. Thomas wrote:
> Ok, almost got it then, I think. Thank you, you've saved me many
hours!
>
> So, I get three or four button and contactor blocks, like this one:
>
>
http://web4.automationdirect.com/adc/Shopping/Catalog/Pushbuttons_-z-_Switches_-z-_Indicators/Eaton_Cutler-Hammer_22mm_(E22_Series)/Emergency_Stop_-z-_Mushroom_Pushbuttons_-a-_Stations/E22JLB2N8B
>
> I then connect them to a 40 amp, 24 volt contactor, such as this 2
pole
> model:
>
> http://store.yahoo.com/waterheater/c2con40amp2p.html
>
> I also connect one side of the contactor to a 30 amp/220 volt circuit
on
> my existing subpanel, and the other side to the input of the new
subpanel.
>
> Assuming all this is correct, I only have one question - does the
> contactor step the 220 down to 24v for the buttons? Or do I need a
> seperate transformer to do that? Something like this, maybe?
>
>
http://www.surpluscenter.com/item.asp?UID=2004120915272670&item=15-1164&catname=electric
>
> Thanks again!
>
> -BAT


You might want to consider some start buttons to turn it all back on.
They make pushbutton stations that have large "panic" buttons for the
stop button and also include a start. Also, check your codes as to what
gauge wire is going to need to feed your subpanel. See if they will
allow your particular setup.

I have some of those definite purpose contactors and didn't really know
a use for them. Now you have me thinking. I'm not plannning what you're
planning. But, the noggin is smoking. As I've never used one and don't
know their proper wiring, I do have this question. Can several
pushbutton stations operate the same contactor or would there need to
be a series of contactors? I've only wired magnetic starters and one
per machine. I haven't tried to feed a subpanel with them.

I look forward to seeing how this thread progresses when some of the
electrician types get home from work.
Eric T. in MN

ps. Brett, where are you located?

Brett A. Thomas wrote:
> Ok, almost got it then, I think. Thank you, you've saved me many
hours!
>
> So, I get three or four button and contactor blocks, like this one:
>
>
http://web4.automationdirect.com/adc/Shopping/Catalog/Pushbuttons_-z-_Switches_-z-_Indicators/Eaton_Cutler-Hammer_22mm_(E22_Series)/Emergency_Stop_-z-_Mushroom_Pushbuttons_-a-_Stations/E22JLB2N8B
>
> I then connect them to a 40 amp, 24 volt contactor, such as this 2
pole
> model:
>
> http://store.yahoo.com/waterheater/c2con40amp2p.html
>
> I also connect one side of the contactor to a 30 amp/220 volt circuit
on
> my existing subpanel, and the other side to the input of the new
subpanel.
>
> Assuming all this is correct, I only have one question - does the
> contactor step the 220 down to 24v for the buttons? Or do I need a
> seperate transformer to do that? Something like this, maybe?
>
>
http://www.surpluscenter.com/item.asp?UID=2004120915272670&item=15-1164&catname=electric
>
> Thanks again!
>
> -BAT


You might want to consider some start buttons to turn it all back on.
They make pushbutton stations that have large "panic" buttons for the
stop button and also include a start. Also, check your codes as to what
gauge wire is going to need to feed your subpanel. See if they will
allow your particular setup.

I have some of those definite purpose contactors and didn't really know
a use for them. Now you have me thinking. I'm not plannning what you're
planning. But, the noggin is smoking. As I've never used one and don't
know their proper wiring, I do have this question. Can several
pushbutton stations operate the same contactor or would there need to
be a series of contactors? I've only wired magnetic starters and one
per machine. I haven't tried to feed a subpanel with them.

I look forward to seeing how this thread progresses when some of the
electrician types get home from work.
Eric T. in MN

ps. Brett, where are you located?

Hi All,

just one more thought to the emergency switch topic. I also wanted to put
that into my shop but didn't do so up to now.
Reason: My TS has got an electrical brake which is not functioning without
power (required by the local code here for new machines). With a heavy dado
blade on it will stop spinning after 5 seconds with the brake active as
compared to close to a minute w/o.
So before you cut-off power in your shop, make sure your equipment does not
behave similarly.

Regards Matthias


"Brett A. Thomas" <[email protected]> schrieb im Newsbeitrag
news:[email protected]...
> All,
>
> Spent some time trolling the archives and Google, and couldn't really
> find what I was looking for. I suspect in part it's because I'm
> suffering from a Language Gap - there's a specific term for what I'm
> looking for, and I don't know what it is.
>
> So, I apologize in advance if this has been talked to death before, but
> I can't find it, if it is.
>
> First of all, my knee has recovered enough from surgery in the past week
> that I've been spending my free time in the new shop (18' 6" x 19' fully
> detached garage) emptying all the boxes that don't belong there,
> emptying the boxes that do belong there into the hideous cabinetry out
> there, running boxes to recycling, giving things to Goodwill, etc. Very
> exciting! I expect to be able to set the tablesaw back up by this
> weekend! February of last year was the last time I made sawdust.
>
> The walls and ceiling in the shop are exposed studs (16" centers) right
> now. I'm planning on putting drywall up on the ceiling and plywood on
> the walls. But that's not what I want to talk about (THAT is easy to
> find in the archives) - before I can do that, I have to get some wiring
> done. To get the wiring done, I have to make some key decisions.
>
> I'm a bit of a safety freak, and I have two small children (4 & 2).
> Short term I want to keep them out of the shop entirely without
> supervision, and the lock on the garage door will do well with that.
> Long term, I want to let them in the shop, but not let them do anything
> really dangerous without supervision (i.e., anything involving power
> tools). I'm also interested in emergency power cutoffs, mostly for my
> own use. Right now the garage is fed by a 240v 40 amp circuit that
> terminates in a sub panel in the garage. I recognize I may need more in
> the future, but it's enough for now.
>
> Without any thought whatsoever to the practicality or cost, the two big
> things I want are:
>
> A lockout box. I want to be able to leave lights and battery chargers
> on, but throw a switch, put a lock on it, and have no power tools operate.
>
> Several Big Red Buttons. I want to be able to hit a quick disconnect
> from one of several places in the shop, and have it kill the power to
> all the power tools (but not the lights or the battery chargers). Part
> of my problem is that I do not know what the industry Term of Art is for
> these buttons.
>
> Of course, we don't live in a world where practicality and cost aren't
> concerns, so if any requirement I list above is too much work or too
> much expense, I'm willing to rethink. If it's gonna cost me $2000, I
> can lose the emergency cutoffs and just put a lock on the subpanel I
> have and be done with it.
>
> So, here are my questions, and thanks in advance for anyone with the
> knowledge to answer, the inclination to help and the patience to read
> through my long-winded explanation:
>
> 1) What are Big Red Buttons called?
>
> 2) How do they work? Can I wire three circuits through one without
> needing a second subpanel?
>
> 3) What are the lockout box things called? Googling for "lockout box"
> gives me a bunch of storage boxes to store my lockout/tagout keys in. I
> think maybe a "safety switch" is what I want, something like this:
>
http://www.builderdepot.com/browse.ihtml?pid=145815&step=5&prodstoreid=2245
>
> 4) How do *they* work? Can I wire three circuits through one without
> needing a second subpanel?
>
> 5) If you held a gun to my head and said "Do it right now with what you
> know," I'd drop the emergency cutoff switches for now, install a new
> subpanel on a 30A breaker, and put a "safety switch" between the two of
> them. Is this, in fact, the best plan, or am I artificially limiting
> myself by my lack of knowledge?
>
> 6) Stupid question - I have this kooky idea to hook up a 50 ampish
> inline AC ammeter prior to the first subpanel. Is this stupid, or just
> geeky? I think it'd be pretty cool to always know how much juice I'm
> pulling.
>
> Thanks in advance...
>
> -BAT

I had initially replied to your reply to Bill Pounds' reply. However, I
got too random and snipped the entire text and now this stands alone.

You might want to consider a big safety switch like one of these:

[http://www.squared.com/us/products/safety_switches.nsf/unid/A67139009206C76A85256A29004E1A7D/$file/safetyswitchFrameset.htm]

Put this in between your two panels. Make sure you get one with a
lockout. Alternatively, you can place one on the front end of any
circuits that you want to disable.

Ask yourself what all of those panic buttons are going to do for you.
If a child is able to get the machine turned on and gets bitten by its
teeth, then they probably won't be able to get to a safety switch. If
they can't turn it on in the first place, there would be less danger.
You can still cut yourself on a non-powered saw blade. DAMHIKT.
Therefore, you should also lower your Table Saw blade after use. You
should anyway.

If you do go the route of all of the emergency stop buttons, you will
probably also want to have magnetic starters on all of your machines.
That way a machine that was shut down from the power down will not be
restarted on power up.

Another option would be to remove and lock up all of your blades,
chisels, planes, etc in a cabinet.

I'm in a similar situation with little ones and am contemplating some
of the same issues that you are.

Good luck,

Eric T

Hi,
This is not something I know much about, so there could be any number
of flaws in my reasoning, but how about switching (pun intended) things
around: a normally open relay with normally closed stop switches? That
way any tools on the subpanel after the relay will get power only if
there is 24v on the relay. As soon as you hit a stop switch, you open
the 24v circuit and the relay opens. Restore 24v and the relay closes
again. Note that I'm assuming you can get stop switches that are N.C.,
and that will stay open after you push them (as opposed to closing
again as soon as you let go).
Lewis

Its a good thing you got wood to take out your agression on. Now I
understand teh pen name. I previously thought it hads something to do
with your last name.

Don't worry though, I'll still value your woodworking advice. I might
look over my shoulder for those Con-Ed guys though. The power company
doesn't believe in a statute of limitations.

Eric in MN


Pounds on Wood wrote:

> Yea, I know it gets harder, not easier when they get older. I
remember my
> own youth. ...I think of the stuff I did with that, and no
> instruction from dear old dad at all... I can recall:
> -Playing with gasoline on the BBQ and setting my entire shirt sleeve
on
> fire - no burns, just singed hair.
> -Putting power caps from the stud gun in a vice and firing them with
a
> hammer - no injury
> -Welding stuff - might have been bad on my eyes, they aren't too good
today
> -Hooking the welder into the edison power drop above the rain hood
with
> alligator clamps - blew the fuses on a pole somewhere and shut down
the
> neighborhood power - I was smart enough to hide the evidence before
edison
> showed up to repair.
> -Shot my brother in the chest from 50 feet with an arrow - lucky for
us both
> it was the blunt practice points. Actually, luckier for him than me.
Hit
> him dead center too.
> -Shot the cat in the head with the same bow - but we all did that
right?
> --
> Bill Pounds
> http://www.billpounds.com/woodshop

Brett A. Thomas wrote:

> All,
>
> Spent some time trolling the archives and Google, and couldn't really
> find what I was looking for. I suspect in part it's because I'm
> suffering from a Language Gap - there's a specific term for what I'm
> looking for, and I don't know what it is.
>
> So, I apologize in advance if this has been talked to death before,
> but I can't find it, if it is.
>
> First of all, my knee has recovered enough from surgery in the past
> week that I've been spending my free time in the new shop (18' 6" x
> 19' fully detached garage) emptying all the boxes that don't belong
> there, emptying the boxes that do belong there into the hideous
> cabinetry out there, running boxes to recycling, giving things to
> Goodwill, etc. Very exciting! I expect to be able to set the
> tablesaw back up by this weekend! February of last year was the last
> time I made sawdust.
>
> The walls and ceiling in the shop are exposed studs (16" centers)
> right now. I'm planning on putting drywall up on the ceiling and
> plywood on the walls. But that's not what I want to talk about (THAT
> is easy to find in the archives) - before I can do that, I have to get
> some wiring done. To get the wiring done, I have to make some key
> decisions.
>
> I'm a bit of a safety freak, and I have two small children (4 & 2).
> Short term I want to keep them out of the shop entirely without
> supervision, and the lock on the garage door will do well with that.
> Long term, I want to let them in the shop, but not let them do
> anything really dangerous without supervision (i.e., anything
> involving power tools). I'm also interested in emergency power
> cutoffs, mostly for my own use. Right now the garage is fed by a 240v
> 40 amp circuit that terminates in a sub panel in the garage. I
> recognize I may need more in the future, but it's enough for now.
>
> Without any thought whatsoever to the practicality or cost, the two
> big things I want are:
>
> A lockout box. I want to be able to leave lights and battery chargers
> on, but throw a switch, put a lock on it, and have no power tools
> operate.
>
> Several Big Red Buttons. I want to be able to hit a quick disconnect
> from one of several places in the shop, and have it kill the power to
> all the power tools (but not the lights or the battery chargers).
> Part of my problem is that I do not know what the industry Term of Art
> is for these buttons.
>
> Of course, we don't live in a world where practicality and cost aren't
> concerns, so if any requirement I list above is too much work or too
> much expense, I'm willing to rethink. If it's gonna cost me $2000, I
> can lose the emergency cutoffs and just put a lock on the subpanel I
> have and be done with it.
>
> So, here are my questions, and thanks in advance for anyone with the
> knowledge to answer, the inclination to help and the patience to read
> through my long-winded explanation:
>
> 1) What are Big Red Buttons called?
>
> 2) How do they work? Can I wire three circuits through one without
> needing a second subpanel?
>
> 3) What are the lockout box things called? Googling for "lockout
> box" gives me a bunch of storage boxes to store my lockout/tagout keys
> in. I think maybe a "safety switch" is what I want, something like
> this:
> http://www.builderdepot.com/browse.ihtml?pid=145815&step=5&prodstoreid=2245
>
>
> 4) How do *they* work? Can I wire three circuits through one without
> needing a second subpanel?
>
> 5) If you held a gun to my head and said "Do it right now with what
> you know," I'd drop the emergency cutoff switches for now, install a
> new subpanel on a 30A breaker, and put a "safety switch" between the
> two of them. Is this, in fact, the best plan, or am I artificially
> limiting myself by my lack of knowledge?
>
> 6) Stupid question - I have this kooky idea to hook up a 50 ampish
> inline AC ammeter prior to the first subpanel. Is this stupid, or
> just geeky? I think it'd be pretty cool to always know how much juice
> I'm pulling.
>
> Thanks in advance...
>
> -BAT

We called the big red buttons safety switches. They are normally
closed and wired in series to operate a contactor (relay) which would
control the power to the whole shop.

The simplest way would be to have a small subpanel to control the lights
and battery chargers you want left on and the main panel for the tools
would be fed through the contactor. Drop out the contactor with one of
the safety switches and you kill the power to the main panel. A quick
search on motor starters will find one that will do what you want for
under $200

The safety switch you noted above will do what you want manually but if
you want to use push button safety switchs you will need an enclosed
motor starter to kill the power to the main panel.

Rick

I don't5 claim to be an electrician, however I am a former woodworking and
metalworking Industrial arts teacher (program closed and I am now a school
librarian: LONG story!!!) However I still maintain my home shop.

What you are seeking is/was standard equipment in most (if not all) school
shops. The entire shop could (and was whenever the teacher was not there)
turned off from any of several locations within the room. There was usually one
"panic button" per wall. The shop was "turned on" either with a separate key
switch mounted on the wall or by opening the circuit panel and resetting the
main breaker. Frequently the only functioning electricity in the room was the
lighting and the clock outlet.

In my basement, I have most of the lights and power tools on two circuits
though if one of the breakers trips, there is redundant lighting. I could
separate the lighting out and control both these circuits with a single throw
double pole switch which could be locked. (this doesn't give you the panic
buttons" but does give you security and it is cheap! I wired most of the shop
so the switches control outlets fastened to the ceiling joists. These allow 4'
fluorescent tubes to be plugged in or drop cords to be used to power tools as
needed.

Good luck and enjoy your new shop! PS I like the idea of Plywood walls!!




snip: >Spent some time trolling the archives and Google, and couldn't really
>find what I was looking for. I suspect in part it's because I'm
>suffering from a Language Gap - there's a specific term for what I'm
>looking for, and I don't know what it is.

On Thu, 09 Dec 2004 11:40:38 -0800, Brett A. Thomas <[email protected]> wrote:
> All,
>
> Spent some time trolling the archives and Google, and couldn't really
> find what I was looking for.

Just so you know, the word "trolling" in Usenet terms has a pretty
specific meaning, something along the lines of "posting controversial
messages to stir up people and prolong a useless discussion", which
I don't think is what you're really doing.

>
> Without any thought whatsoever to the practicality or cost, the two big
> things I want are:
> A lockout box. I want to be able to leave lights and battery chargers
> on, but throw a switch, put a lock on it, and have no power tools operate.

The easiest way to do this would be to have the big power tools on a
sub-panel, and the outlets on the main panel. Master-switch the whole
sub-panel on and off.

> Several Big Red Buttons. I want to be able to hit a quick disconnect
> from one of several places in the shop, and have it kill the power to
> all the power tools (but not the lights or the battery chargers).

Yup.

> Part
> of my problem is that I do not know what the industry Term of Art is for
> these buttons.

"Emergency Stop" is what most/all of them seem to be marked with.

> Of course, we don't live in a world where practicality and cost aren't
> concerns, so if any requirement I list above is too much work or too
> much expense, I'm willing to rethink. If it's gonna cost me $2000, I
> can lose the emergency cutoffs and just put a lock on the subpanel I
> have and be done with it.

I can't see the e-stop switches adding much cost, even if you run conduit
from them back to the contactor (we call 'em relays). It's easy but
time-consuming work, so it's worth considering doing yourself if you
can get an Electrician to do the design and advise you.

> So, here are my questions, and thanks in advance for anyone with the
> knowledge to answer, the inclination to help and the patience to read
> through my long-winded explanation:
>
> 1) What are Big Red Buttons called?

See above.

> 2) How do they work? Can I wire three circuits through one without
> needing a second subpanel?

Put 'em before the subpanel with all the switched stuff, and let them
control the relay for the whole subpanel.

> 5) If you held a gun to my head and said "Do it right now with what you
> know," I'd drop the emergency cutoff switches for now, install a new
> subpanel on a 30A breaker, and put a "safety switch" between the two of
> them. Is this, in fact, the best plan, or am I artificially limiting
> myself by my lack of knowledge?

No, you're doing it right, the big red buttons juust control that subpanel.
>
> 6) Stupid question - I have this kooky idea to hook up a 50 ampish
> inline AC ammeter prior to the first subpanel. Is this stupid, or just
> geeky? I think it'd be pretty cool to always know how much juice I'm
> pulling.

It's geeky. I'd do it, and wish I had thought of it. Let us know how
that goes, I may just retrofit my shop.

Dave Hinz

On Thu, 09 Dec 2004 13:02:20 -0800, Brett A. Thomas <[email protected]> wrote:
> Sorry to follow up to my own follow up, but I think I've figured out more.

OK!

> That's an "N.C." which I presume stands for "Normally closed." So, when
> you push it, it opens a circuit (briefly? Until it's pulled back out or
> released some other way?)

As long as you hold it, which is long enough to trip the relay and/or
breaker your 24v is controlling.

> That circuit is then hooked up to - what? A relay, I guess, but is
> there a special name for it? Or do I just get a 30A relay someplace?
> And what voltage (and AC or DC) do I run the contact blocks at?

The control circuit is usually 24v (AC - it'd be spelled 24V if it was DC).

I'd switch the whole subpanel rather than a bunch of individual breakers,
it's cheaper that way. Current capacity of the contacter (relay) should be
more than the total current of the breakers it's feeding.

Many buttons to control one relay, which switches off many breakers in
the entire subpanel all at once. Simplest, most cost-effective
way to do what you want to do, I think.

Dave Hinz

On Thu, 09 Dec 2004 22:30:55 GMT, Ron Short <[email protected]> wrote:
> Dave, if he switched the whole subpanel then how would he still have lights?

That's why it's a sub-panel. The smaller outlets and the lights would
be on the main panel for the shop.

> He'd have to have a separate sub panel for the lights and batteries and
> whatever else he didn't want switched. I think that was an original
> requirement....not sure if it changed.

Nope, no change.

On Fri, 10 Dec 2004 19:42:50 +0100, Juergen Hannappel <[email protected]> wrote:
> [email protected] writes:
>
>
> [... something similar to oridinary practise ]
>
>> again. Note that I'm assuming you can get stop switches that are N.C.,
>> and that will stay open after you push them (as opposed to closing
>> again as soon as you let go).
>
> ANY safety switch is N.C. and will stay in once it's pressed, some can
> be released by pulling it out, others need a key for rearming them.

Our experience differs; I have seen some that are momentary contact, but
they were connected to systems which dropped a relay based on that momentary
opening of the contacts.

I don't know how old that system was, however. But momentary-contact e-stop
mechanisms _do_ exist, and on medical equipment even.

Dave Hinz

Ron Short wrote:
> Dave, if he switched the whole subpanel then how would he still have lights?
> He'd have to have a separate sub panel for the lights and batteries and
> whatever else he didn't want switched. I think that was an original
> requirement....not sure if it changed.

One of my original questions was "do I need a second subpanel?" and it
seems like the answer is "yes."

-BAT

Dave Hinz wrote:
> On Thu, 09 Dec 2004 11:40:38 -0800, Brett A. Thomas <[email protected]> wrote:
> I can't see the e-stop switches adding much cost, even if you run conduit
> from them back to the contactor (we call 'em relays). It's easy but
> time-consuming work, so it's worth considering doing yourself if you
> can get an Electrician to do the design and advise you.

Dave,

Thanks for the info so far, this has helped a lot.

I'm planning on doing it myself, which is part of why I'm really trying
to understand the components.

So, it sounds like what I want is an "emergency stop" button, but the
key thing I needed to know is that it's connected to a "contactor." I
get a big red button, say, one of these beauties:

http://www.recycledgoods.com/ProductDetails.aspx?productID=12196

And hook it to a "contact block," which then runs (24 V?) back to a
relay at the subpanel which causes the shutoff. Is that correct, and,
are there any other special terms that would be helpful in searching for
suppliers?

Thanks again. Oh, and for those searching Usenet archives in the future:

Big Red Button = Emergency Stop button hooked to a contact block or
contactor. You might also be looking for a relay, emergency switch or a
switch.

If someone had done that ten years ago I wouldn't be bugging you folks,
now. :)

-BAT

Sorry to follow up to my own follow up, but I think I've figured out more.

It looks like I hook up a button/contact block. I like the look of this
one:

http://web4.automationdirect.com/adc/Shopping/Catalog/Pushbuttons_-z-_Switches_-z-_Indicators/Eaton_Cutler-Hammer_22mm_(E22_Series)/Emergency_Stop_-z-_Mushroom_Pushbuttons_-a-_Stations/E22JLB2N8B

That's an "N.C." which I presume stands for "Normally closed." So, when
you push it, it opens a circuit (briefly? Until it's pulled back out or
released some other way?)

That circuit is then hooked up to - what? A relay, I guess, but is
there a special name for it? Or do I just get a 30A relay someplace?
And what voltage (and AC or DC) do I run the contact blocks at?

If I figure it out on my own, I'll followup here...

-BAT

Ok, almost got it then, I think. Thank you, you've saved me many hours!

So, I get three or four button and contactor blocks, like this one:

http://web4.automationdirect.com/adc/Shopping/Catalog/Pushbuttons_-z-_Switches_-z-_Indicators/Eaton_Cutler-Hammer_22mm_(E22_Series)/Emergency_Stop_-z-_Mushroom_Pushbuttons_-a-_Stations/E22JLB2N8B

I then connect them to a 40 amp, 24 volt contactor, such as this 2 pole
model:

http://store.yahoo.com/waterheater/c2con40amp2p.html

I also connect one side of the contactor to a 30 amp/220 volt circuit on
my existing subpanel, and the other side to the input of the new subpanel.

Assuming all this is correct, I only have one question - does the
contactor step the 220 down to 24v for the buttons? Or do I need a
seperate transformer to do that? Something like this, maybe?

http://www.surpluscenter.com/item.asp?UID=2004120915272670&item=15-1164&catname=electric

Thanks again!

-BAT

robdingnagian1 wrote:
> You might want to consider some start buttons to turn it all back on.
> They make pushbutton stations that have large "panic" buttons for the
> stop button and also include a start. Also, check your codes as to what
> gauge wire is going to need to feed your subpanel. See if they will
> allow your particular setup.

Yes, that's actually one of my questions - exactly how do I turn this
back on? And, obviously, I'll need to include my building inspector in
all this. But I need to be able to talk vaguely intelligently about
what I'm going to do, first.

As to the question, I think of two basic possibilities:

Either, as you suggest, there needs to be a "turn it all back on" switch
that resets the relay somehow, or, the way this is *supposed* to be
wired is so that, when the relay closes, it causes a dead short and
trips the breaker on the original subpanel, and when the power cuts the
relay opens automatically. I have no opinion about whether that's a
good idea, or if it works, but, if it's not, I'm expecting to get flamed
right about now. :)

All the threads I've seen previously on this subject have tended to the
"tell an electrician you want emergency stops" type of answers, but it
doesn't seem to me this should really be rocket science, and I hope we
can figure it out and document it for everyone else.

> ps. Brett, where are you located?

I'm in San Carlos, CA.

-BAT

robdingnagian1 wrote:
> I had initially replied to your reply to Bill Pounds' reply. However, I
> got too random and snipped the entire text and now this stands alone.
>
> You might want to consider a big safety switch like one of these:
>
> [http://www.squared.com/us/products/safety_switches.nsf/unid/A67139009206C76A85256A29004E1A7D/$file/safetyswitchFrameset.htm]

Thanks for the suggestion and link. Am definitely planning on doing
this for kid safety (and, like I said, not just my own - don't want any
neighborhood hoodlums bleeding all over my shop either if they get in).

> Ask yourself what all of those panic buttons are going to do for you.
> If a child is able to get the machine turned on and gets bitten by its
> teeth, then they probably won't be able to get to a safety switch. If
> they can't turn it on in the first place, there would be less danger.

If you look at my original article, I'm asking about buttons and safety
switches. The switches are to lock out the kids, the buttons are for
me, when I'm in the shop. It seems like they won't add much to the cost
of the wiring, and as long as I don't have any wall coverings, it should
be easy enough to toss 'em in.

> If you do go the route of all of the emergency stop buttons, you will
> probably also want to have magnetic starters on all of your machines.
> That way a machine that was shut down from the power down will not be
> restarted on power up.

Excellent point. I do on my tablesaw and jointer, but I'm not 100% sure
of my planer.

> Another option would be to remove and lock up all of your blades,
> chisels, planes, etc in a cabinet.
>
> I'm in a similar situation with little ones and am contemplating some
> of the same issues that you are.

Well, like I said, with them at the ages they are now (2 & 4), plan A is
to keep the garage locked. Obviously I don't want them touching knives,
saws, chisels, etc. at this age. But I'm thinking there'll be a point
where I'll let them in the garage under minimal supervision but not let
them use powertools under minimal supervision. While you are correct
that you can cut yourself on a human-powered saw, I don't think I've
heard of anyone cutting his own arm off with one - at least by accident.
;)

-BAT

Pounds on Wood wrote:
> Sounds like a lot of locks, when the best solution might be a lock on the
> garage/shop door. Kids don't need to be playing unsupervised in a garage
> even if it only houses the family car.

Well, in the short term that's the plan - when they're this age, they
never need to be out there.

I know when I was, say 12, I spent a lot of time relatively unsupervised
in the garage. I don't think they should have to get me to get a
(neander) saw. My *hope* is that, when they're that age, I won't have
to worry about them around power tools, either - I know when I was 12
you couldn't've paid me enough to turn on my Grandfather's radial arm
saw, I thought it was terrifying (even though I'd worked on it with
him). But we won't know for sure until we get there, and there are
always kids' friends who may be over and less intelligent than my own
genius progeny ;). Whatever the exact age, I expect that there will be
a point when I'm willing to trust them to use neander tools but not
power tools.

-BAT

"Brett A. Thomas" <[email protected]> wrote in message
news:[email protected]...
> Ok, almost got it then, I think. Thank you, you've saved me many hours!
>
> So, I get three or four button and contactor blocks, like this one:
>
>
http://web4.automationdirect.com/adc/Shopping/Catalog/Pushbuttons_-z-_Switches_-z-_Indicators/Eaton_Cutler-Hammer_22mm_(E22_Series)/Emergency_Stop_-z-_Mushroom_Pushbuttons_-a-_Stations/E22JLB2N8B
>
> I then connect them to a 40 amp, 24 volt contactor, such as this 2 pole
> model:
>
> http://store.yahoo.com/waterheater/c2con40amp2p.html
>
> I also connect one side of the contactor to a 30 amp/220 volt circuit on
> my existing subpanel, and the other side to the input of the new subpanel.
>
> Assuming all this is correct, I only have one question - does the
> contactor step the 220 down to 24v for the buttons? Or do I need a
> seperate transformer to do that? Something like this, maybe?
>
>
http://www.surpluscenter.com/item.asp?UID=2004120915272670&item=15-1164&catname=electric


A contactor is just a big relay and steps down nothing. You will need a 24V
source You will also need a N.O. momentary contact switch (probably a key
type) and a 24V relay to complete your system. Now I know that this sounds
confusing but let me explain where I'm coming from. With what you seem to
be describing, you are going to connect your contactor between the existing
sub panel and a new one that will be switched by it. This is cool and is
something I am considering as well. To control the contactor, it looks like
you are going to hook up its field coil to a 24V source with 3 or 4 push
button shut down switches in a loop configuration so that if any of the
buttons are pressed, the contactor will open and kill the power. While this
sounds good, there are a couple of problems. These push button switches are
momentary action type which means that they only work when held in position.
IOW, they will open (turn off) only for as long as you hold the switch. Now
this is where problem comes in. If your 24V source is getting power from
something that is not controlled by the contactor, the contactor will only
open (cut power) when one of the switches is being pressed and as soon as
you let it go, the power will be restored to the contactor and it will close
again and re-power the new box. This will not be of much help. If you
supply power to the 24V source comes from the contactor supplied side, you
will never have power to turn the contactor on. So what do you need to do??
You need to build a self energizing relay to control the contactor and that
is where the 24V relay comes in and you will need a momentary contact N.O.
switch to activate it.. I can email you a schematic if you need it



--
If at first you don't succeed, you're not cut out for skydiving

"TBone" <[email protected]> wrote in message
news:[email protected]...
>
> "Brett A. Thomas" <[email protected]> wrote in message
> news:[email protected]...
> > Ok, almost got it then, I think. Thank you, you've saved me many hours!
> >
> > So, I get three or four button and contactor blocks, like this one:
> >
> >
>
http://web4.automationdirect.com/adc/Shopping/Catalog/Pushbuttons_-z-_Switches_-z-_Indicators/Eaton_Cutler-Hammer_22mm_(E22_Series)/Emergency_Stop_-z-_Mushroom_Pushbuttons_-a-_Stations/E22JLB2N8B
> >
> > I then connect them to a 40 amp, 24 volt contactor, such as this 2 pole
> > model:
> >
> > http://store.yahoo.com/waterheater/c2con40amp2p.html
> >
> > I also connect one side of the contactor to a 30 amp/220 volt circuit on
> > my existing subpanel, and the other side to the input of the new
subpanel.
> >
> > Assuming all this is correct, I only have one question - does the
> > contactor step the 220 down to 24v for the buttons? Or do I need a
> > seperate transformer to do that? Something like this, maybe?
> >
> >
>
http://www.surpluscenter.com/item.asp?UID=2004120915272670&item=15-1164&catname=electric
>
>
> A contactor is just a big relay and steps down nothing. You will need a
24V
> source You will also need a N.O. momentary contact switch (probably a
key
> type) and a 24V relay to complete your system. Now I know that this
sounds
> confusing but let me explain where I'm coming from. With what you seem to
> be describing, you are going to connect your contactor between the
existing
> sub panel and a new one that will be switched by it. This is cool and is
> something I am considering as well. To control the contactor, it looks
like
> you are going to hook up its field coil to a 24V source with 3 or 4 push
> button shut down switches in a loop configuration so that if any of the
> buttons are pressed, the contactor will open and kill the power. While
this
> sounds good, there are a couple of problems. These push button switches
are
> momentary action type which means that they only work when held in
position.
> IOW, they will open (turn off) only for as long as you hold the switch.
Now
> this is where problem comes in. If your 24V source is getting power from
> something that is not controlled by the contactor, the contactor will only
> open (cut power) when one of the switches is being pressed and as soon as
> you let it go, the power will be restored to the contactor and it will
close
> again and re-power the new box. This will not be of much help. If you
> supply power to the 24V source comes from the contactor supplied side, you
> will never have power to turn the contactor on. So what do you need to
do??
> You need to build a self energizing relay to control the contactor and
that
> is where the 24V relay comes in and you will need a momentary contact N.O.
> switch to activate it.. I can email you a schematic if you need it
>

Just get a good contactor ( about nema #2) and you can put an aux N.O.
contact block on it to perform the "latch" function

William....

>
>
> --
> If at first you don't succeed, you're not cut out for skydiving
>
>

robdingnagian1 wrote:

>Brett A. Thomas wrote:
>
>
>>Ok, almost got it then, I think. Thank you, you've saved me many
>>
>>
>hours!
>
>
>>So, I get three or four button and contactor blocks, like this one:
>>
>>
>>
>>
>http://web4.automationdirect.com/adc/Shopping/Catalog/Pushbuttons_-z-_Switches_-z-_Indicators/Eaton_Cutler-Hammer_22mm_(E22_Series)/Emergency_Stop_-z-_Mushroom_Pushbuttons_-a-_Stations/E22JLB2N8B
>
>
>>I then connect them to a 40 amp, 24 volt contactor, such as this 2
>>
>>
>pole
>
>
>>model:
>>
>>http://store.yahoo.com/waterheater/c2con40amp2p.html
>>
>>I also connect one side of the contactor to a 30 amp/220 volt circuit
>>
>>
>on
>
>
>>my existing subpanel, and the other side to the input of the new
>>
>>
>subpanel.
>
>
>>Assuming all this is correct, I only have one question - does the
>>contactor step the 220 down to 24v for the buttons? Or do I need a
>>seperate transformer to do that? Something like this, maybe?
>>
>>
>>
>>
>http://www.surpluscenter.com/item.asp?UID=2004120915272670&item=15-1164&catname=electric
>
>
>>Thanks again!
>>
>>-BAT
>>
>>
>
>
>You might want to consider some start buttons to turn it all back on.
>They make pushbutton stations that have large "panic" buttons for the
>stop button and also include a start. Also, check your codes as to what
>gauge wire is going to need to feed your subpanel. See if they will
>allow your particular setup.
>
>I have some of those definite purpose contactors and didn't really know
>a use for them. Now you have me thinking. I'm not plannning what you're
>planning. But, the noggin is smoking. As I've never used one and don't
>know their proper wiring, I do have this question. Can several
>pushbutton stations operate the same contactor or would there need to
>be a series of contactors?
>
Yes you would wire the stop contactors in series to drop out the
contactor and the start ones in parallel to start it.


>I've only wired magnetic starters and one
>per machine. I haven't tried to feed a subpanel with them.
>
>I look forward to seeing how this thread progresses when some of the
>electrician types get home from work.
>Eric T. in MN
>
>ps. Brett, where are you located?
>
>
>

I work for a large temperature controls company and we use the contactors
you are discussing all of the time. What you are trying to do is set up an
electrical circuit where you have multiple switches wired all in series. The
voltage used to power the contactor is supplied by a transformer. It steps
the voltage down from 120 VAC to 24 VAC. One side of the transformer (the
common) is wired to the common side of the transformer, the other is wired
through the normally closed switches, one after another, to the other side
of the contactor coil. If any one switch is hit, the circuit will open
preventing the contractor from being powered, killing the power to your
power tools.

Depending on your local codes, you can mount a 24VAC transformer at the
circuit breaker panel and route the wires through the wall to the switches,
without conduit. The 24VAC transformer should be sized to handle the
contactor while not exceeding a rating of 100VA (about 4 amps). That will
meet the requirements for class 2 wiring, and can normally be run with
thermostat wire. A 40VA, 24 VAC transformer will more than do the job for
you assuming a typical 30 or 40 amp contactor.

"robdingnagian1" <[email protected]> wrote in message
news:[email protected]...
>
> Brett A. Thomas wrote:
> > Ok, almost got it then, I think. Thank you, you've saved me many
> hours!
> >
> > So, I get three or four button and contactor blocks, like this one:
> >
> >
>
http://web4.automationdirect.com/adc/Shopping/Catalog/Pushbuttons_-z-_Switches_-z-_Indicators/Eaton_Cutler-Hammer_22mm_(E22_Series)/Emergency_Stop_-z-_Mushroom_Pushbuttons_-a-_Stations/E22JLB2N8B
> >
> > I then connect them to a 40 amp, 24 volt contactor, such as this 2
> pole
> > model:
> >
> > http://store.yahoo.com/waterheater/c2con40amp2p.html
> >
> > I also connect one side of the contactor to a 30 amp/220 volt circuit
> on
> > my existing subpanel, and the other side to the input of the new
> subpanel.
> >
> > Assuming all this is correct, I only have one question - does the
> > contactor step the 220 down to 24v for the buttons? Or do I need a
> > seperate transformer to do that? Something like this, maybe?
> >
> >
>
http://www.surpluscenter.com/item.asp?UID=2004120915272670&item=15-1164&catname=electric
> >
> > Thanks again!
> >
> > -BAT
>
>
> You might want to consider some start buttons to turn it all back on.
> They make pushbutton stations that have large "panic" buttons for the
> stop button and also include a start. Also, check your codes as to what
> gauge wire is going to need to feed your subpanel. See if they will
> allow your particular setup.
>
> I have some of those definite purpose contactors and didn't really know
> a use for them. Now you have me thinking. I'm not plannning what you're
> planning. But, the noggin is smoking. As I've never used one and don't
> know their proper wiring, I do have this question. Can several
> pushbutton stations operate the same contactor or would there need to
> be a series of contactors? I've only wired magnetic starters and one
> per machine. I haven't tried to feed a subpanel with them.
>
> I look forward to seeing how this thread progresses when some of the
> electrician types get home from work.
> Eric T. in MN
>
> ps. Brett, where are you located?
>

"Brett A. Thomas" <[email protected]> wrote in message
news:[email protected]...
> Pounds on Wood wrote:
> > Sounds like a lot of locks, when the best solution might be a lock on
the
> > garage/shop door. Kids don't need to be playing unsupervised in a
garage
> > even if it only houses the family car.
>
> Well, in the short term that's the plan - when they're this age, they
> never need to be out there.
>
> I know when I was, say 12, I spent a lot of time relatively unsupervised
> in the garage. I don't think they should have to get me to get a
> (neander) saw. My *hope* is that, when they're that age, I won't have
> to worry about them around power tools, either - I know when I was 12
> you couldn't've paid me enough to turn on my Grandfather's radial arm
> saw, I thought it was terrifying (even though I'd worked on it with
> him). But we won't know for sure until we get there, and there are
> always kids' friends who may be over and less intelligent than my own
> genius progeny ;). Whatever the exact age, I expect that there will be
> a point when I'm willing to trust them to use neander tools but not
> power tools.
>
> -BAT

Good LUCK! When I was about 10 years old my father want to keep me from
running the table saw so he installed a fused switch on it with a paddle
lock on the switch lever.... Thought it was all safe.... Wrong answer:-)
it did not lock the fuse cover, so I just unplugged it ( did not want a
nasty shock:-) and jumpered around the fuse and switch and then plugged it
in to turn it on and unplugged it for off.... BTW I still have all my
fingers!

William.....

[email protected] writes:


[... something similar to oridinary practise ]

> again. Note that I'm assuming you can get stop switches that are N.C.,
> and that will stay open after you push them (as opposed to closing
> again as soon as you let go).

ANY safety switch is N.C. and will stay in once it's pressed, some can
be released by pulling it out, others need a key for rearming them.
You can also have a rope attached to special emergency switches, so
that when you pull the rope the power goes away, they are used for
example along converor belts or other large machinery that's hard to
secure with ordinary switches.
--
Dr. Juergen Hannappel http://lisa2.physik.uni-bonn.de/~hannappe
mailto:[email protected] Phone: +49 228 73 2447 FAX ... 7869
Physikalisches Institut der Uni Bonn Nussallee 12, D-53115 Bonn, Germany
CERN: Phone: +412276 76461 Fax: ..77930 Bat. 892-R-A13 CH-1211 Geneve 23

Dave, if he switched the whole subpanel then how would he still have lights?
He'd have to have a separate sub panel for the lights and batteries and
whatever else he didn't want switched. I think that was an original
requirement....not sure if it changed.

> I'd switch the whole subpanel rather than a bunch of individual breakers,
> it's cheaper that way. Current capacity of the contacter (relay) should
be
> more than the total current of the breakers it's feeding.

> Dave Hinz
>