Wood Shop
- Thread starter laketime
- Start date
- Status
- Location
- Simi Valley, CA
Open pole barn with a dust collection system, I would just say that things need to be dust proof, which would be anything that was approved for a wet location.
You might want to interlock the dust collector to the dust producing items. But this is hard with hand tools. Also be careful with "wet locations" and "rainproof". rainproof items are designed for falling water and don't prevent airborne dust from entering. I am not sure which NEMA classifician is used for wet location, but the NEC 502 talks about using dust tight(NEMA 12) enclosures for hazardous dust enviroments. If I think there may be dust, I spec NEMA 12 enclosures, it just helps keep the stuff clean.
renosteinke
Senior Member
- Location
- NE Arkansas
Wet location does NOT equal dust proof.
I'm willing to give a NEMA 4 gasketed enclosure the benefit of the doubt, but the usual NEMA 3R 'raintight' stuff is rather good at getting filled with sawdust.
Motors ought to be TEFC- though, again, I'm willing to accept factory motors on the machinery. I'm willing to trust a saw maker to know something about making saws.
Dust collection is a bit touchy. As a commercial-size shop, the system is likley large enough that you will need to use metal duct and ground / bond the pieces together.
Not all sawdust is a hazard. The coarse dust from the table saw is not as troublesome as the fine dust from the sander, and the wood chips from the planer are of very little concern. Varnish and paint -be they solvent fumes, overspray, or sanding dust - are a very serious concern.
I'm willing to give a NEMA 4 gasketed enclosure the benefit of the doubt, but the usual NEMA 3R 'raintight' stuff is rather good at getting filled with sawdust.
Motors ought to be TEFC- though, again, I'm willing to accept factory motors on the machinery. I'm willing to trust a saw maker to know something about making saws.
Dust collection is a bit touchy. As a commercial-size shop, the system is likley large enough that you will need to use metal duct and ground / bond the pieces together.
Not all sawdust is a hazard. The coarse dust from the table saw is not as troublesome as the fine dust from the sander, and the wood chips from the planer are of very little concern. Varnish and paint -be they solvent fumes, overspray, or sanding dust - are a very serious concern.
- Location
- Simi Valley, CA
Wood shops are not classified the way they used to be. My point with the Bell type boxes was, at least they don't have the extra holes like a 4s box does, so you'll keep most of the dust out of the box at least.
They found that the amount of dust you would need to cause an explosion would be so much that you wouldn't be able to see your hand in front of your face.
They found that the amount of dust you would need to cause an explosion would be so much that you wouldn't be able to see your hand in front of your face.
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
For a "wood shop" only, it most likely wouldn't need to be classified at all; and, if it were, it would be Class III where the installation difference between Division 1 and 2 is negligible. See Section 503.10(A) for Class III, Division 1 and note Section 503.10(B) for Division 2 effectively refers right back to 503.10(A). Also note and all other Art 503 Sections apply to both Division 1 and 2.
Basically everything needs to be dusttight (not "dust proof"). Table 110.28 FPN [2011 NEC] indicates how Enclosure Types are recognized. BTW virtually nothing is required to be listed for Class III.
The only other significant considerations beyond an "ordinary location" installation is avoiding over-heating exterior surfaces and Grounding & Bonding (503.30) which is over-kill for Class III IMO, but it is what it is.
Basically everything needs to be dusttight (not "dust proof"). Table 110.28 FPN [2011 NEC] indicates how Enclosure Types are recognized. BTW virtually nothing is required to be listed for Class III.
The only other significant considerations beyond an "ordinary location" installation is avoiding over-heating exterior surfaces and Grounding & Bonding (503.30) which is over-kill for Class III IMO, but it is what it is.
- Status