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#103746 - 11/08/02 02:54 AM Bewildered! Designed by the Woodshop Supervisor
Joe Tedesco Offline
Member
Registered: 10/07/00
Posts: 2749
Loc: Boston, Massachusetts USA


Bewildered! Designed by the woodshop supervisor!

The explosion proof switch probably costs more than the saw equipment.
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Joe Tedesco, NEC Consultant
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#103747 - 11/08/02 04:32 AM Re: Bewildered! Designed by the Woodshop Supervisor
jdevlin Offline
Member
Registered: 08/07/02
Posts: 402
Loc: welland ontario canada
Sawdust can be an explosion hazard just like grain dust if it is fine enough.
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#103748 - 11/08/02 04:55 AM Re: Bewildered! Designed by the Woodshop Supervisor
Joe Tedesco Offline
Member
Registered: 10/07/00
Posts: 2749
Loc: Boston, Massachusetts USA
True

Quote:
Class III locations usually include textile mills that process cotton, rayon, and so on, where easily ignitible fibers or combustible flyings are present in the manufacturing process. Sawmills and other woodworking plants, where sawdust, wood shavings, and combustible fibers or flyings are present, may also become hazardous. If wood flour (dust) is present, the location is a Class II, Group G location, not a Class III location.
www.necdirect.org




[This message has been edited by Joe Tedesco (edited 11-08-2002).]
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#103749 - 11/08/02 06:07 AM Re: Bewildered! Designed by the Woodshop Supervisor
spyder Offline
Member
Registered: 10/14/02
Posts: 210
Loc: Massachusetts
Better safe than sorry. But still seems a little extreme.
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#103750 - 11/08/02 06:35 AM Re: Bewildered! Designed by the Woodshop Supervisor
Redsy Offline
Member
Registered: 03/28/01
Posts: 2056
Loc: Bucks County PA
There's more to this than meets the eye.
That sure looks like a Class 1, Div.1 disconnect. What about the conduit seal?
What about the NEMA 12 enclosure fed by
sealtite?

Let's play "Guess the Classification"

[This message has been edited by Redsy (edited 11-08-2002).]
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#103751 - 11/08/02 11:36 AM Re: Bewildered! Designed by the Woodshop Supervisor
SAFTENG Offline
Member
Registered: 09/04/01
Posts: 136
Loc: Cincinnati, OH, USA
I thought that saw dust would have fallen into Class II locations. Class I is flammable vapors and gases, Class II is dust, and Class III is Ignitable Fibers and Flyings??? Although wood dust is not exclusively mentioned in the UL classifications, would it not be considered a Class II location. Just asking the elctrical experts.

Bryan www.SAFTENG.net
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#103752 - 11/08/02 02:07 PM Re: Bewildered! Designed by the Woodshop Supervisor
JBD Offline
Member
Registered: 07/12/01
Posts: 599
Loc: WI, USA
The simple presence of wood saw dust does not create a Class II hazardous location. If it did all of our circular saws and sanders would need to be dust ignition-proof.

According to Killark's 1999 National Electrical Code Review & Application Guide " To be considered a "dust" the combustible material must exist as a finely divided solid of 420 microns (0.420 mm) or less. Such a dust will pass through a No. 40 U.S. sieve."
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#103753 - 11/08/02 04:46 PM Re: Bewildered! Designed by the Woodshop Supervisor
Roger Offline
Member
Registered: 05/18/02
Posts: 1716
Loc: N.C.
The dust shouldn't be a problem in this case.

Check out the below floor dust collector.

But look in the background, there's another one of these switches.

BTW, The band saw is mighty high dollar itself.

Roger
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#103754 - 11/11/02 03:13 AM Re: Bewildered! Designed by the Woodshop Supervisor
Trainwire Offline
Member
Registered: 03/15/02
Posts: 360
Loc: Strasburg,PA,USA
Are you sure we are looking at just a disconnect?
That gizmo sure looks like a rotary three phase converter to me.
But then I have been known to be wrong, on numerous occasions

TW
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#103755 - 11/11/02 04:32 AM Re: Bewildered! Designed by the Woodshop Supervisor
Redsy Offline
Member
Registered: 03/28/01
Posts: 2056
Loc: Bucks County PA
Roger,
Good eye with the additional disco. Also, above the (non-xp)panel is what appears to me an explosion-proof j-box of similar classification.
Either somone got a deal on surplus or stolen materials, or some contractor sold the owner a line of bull.

[This message has been edited by Redsy (edited 11-11-2002).]
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