This is a topic that was brought up awhile ago and I meant to post some pictures I had taken. This system is a 2hp 'Grizzly' brand Dust Collector (specs say 1550 CFM) that my Dad installed down in his basement woodshop following procedures outlined in a book that he bought. Model was similar to this: (from www.Grizzly.com )



Here are pages from the book describing 2 installation procedures:





more pictures to follow...
Bill

He decided to run the wires on the inside and outside to be extra sure:

no way..... theres no need for all that earthing,,the metal junctions are connected via plastic pipes,, how can they become live?????

Paul,

Admitedly, this may be more than is really necessary, but it was done to discharge static electrical buildup, as recommended by a book (shown) on how to install Dust-collection systems.

Bill

Roger that Bill. If you read the NFPA code on static electricity (OK the number escapes me at the moment) you will find you ALWAYS must run a conductor alongside your plastic piping in many hazardous or static prone areas.

Folks that are shooting sawdust through plastic pipes with no ground are living pretty dangerously. The power in one good spark can set up a very dangerous explosion.

I had to get into this very heavy when we did the fuel farm at Dulles, it's pretty amazing how much electrical buildup you can get with fuel running through pipes. The fuel never really touches the pipe due to differing polarity of fuel and pipe.

Pretty interesting, but a bit thick for quick answer.

Many years ago, I worked for Tiffany & Co. The polishing of silver and the static it produced, gave many polishers a good jolt and set many a dust collector on fire. The only way we could somewhat control static was to run #4 bare copper through the pipes, dust hoods and bond everything in the area. On dry and cold days we still would get static discharges. we had to attach a ground wire with a clip lead.

I learned about this the hard way,(as with most things), while taking down a PVC vacuum transfer system for documents (the type that sends little bottles through it).
The sttic zonk knocked me clean off of an aluminum ladder, and I sprained my ankle. This gave me some time to figure out what went wrong.
In retrospect, 25 years or so later, I was very lucky to have been just a few feet off of the ground...S

My 2-year-old's hair stands on end when he slides down his plastic slide...

Bill,
Having had a static shock myself off of an Industrial D/Collection system, I know that those grounding wires will pay for themselves.
BTW Bill, good pictures!.


[This message has been edited by Trumpy (edited 06-20-2003).]

I seem to recall Fine Homebuilding running an article, which asserted that the codes (requiring such grounding) did not apply, nor was there an ignition hazard present, in dust collection systems of the size likely to be found in a home shop. Industrial size systems being another matter.
Anyone out there have any primary data available?