# More Questions On Extraction Earthing



## Keith Biggin (Nov 3, 2010)

Hi Gents

I'm new to the forum and haven't looked for answers in other threads. However, any advice or redirection appreciated. I've recently completed a metal pipe based system at home. Its a fantastic sucker based on a 3000 cu meter/hour machine and 180mm ducting stepping down to machine requirements close to the machines. Its a crazy indulgence but its been great fun building it. The extractor is in an enclosure not much bigger than the extrator itself (two outside wall, two chipboard walls). Access to the extractor is through two removable doors on one of the chipboard walls. The enclosure is lined with a combination of dense sound insulation and old carpet and exhausted to the outside by a rectangular carpet lined chipboard tunnel with sound baffles. The tunnel is at least 50% larger than the 180mm inlet hence exhaust air speed is down. Noise inside the workshop is right down...its a great success. My question concerns earthing the enclosure. Should I be concerned with earthing the inside of the enclosure and exhaust given that most dust will have been filtered out through the 5 micro filter bags. If so how?? Regards Keith


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## woodnthings (Jan 24, 2009)

*Hey Keith..*

Sounds like you have darn near a "commercial" system and I could not figure out what you meant by "earthing" until I read the whole thread. We call it "grounding" here and now that makes more sense to me and hopefully others here. 
Basically commercial systems should be grounded and are by virtue of the use of metal duct work. The enclosure will have a natural ground and with the collector inside if it sits on a concrete slab will also be "grounded". If the electrical system provides for an earth ground within the panel then you collector will also be grounded. 
If you are really concerned drive a grounding rod near the enclosure
and run a wire to the frame of your collector. JMO.
FWI
Home shop systems using PVC are a subject of great debate everywhere forums discuss it. Static shock from the movement of air and wood articles can be annoying, even painful but all the discussions I've read pretty much conclude that grounding a PVC duct system is not really necessary to prevent a dust explosion. Wires inside, wires outside etc all combinations have been tried, some folk swear by them others say ppfffrttt, who needs 'em. Here's a thread from here and within it some good links: http://www.woodworkingtalk.com/f7/static-hazard-dust-collection-19591/ :thumbsup: bill
This one especially:http://www.waterfront-woods.com/Articles/Electricity/static.htm


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## Keith Biggin (Nov 3, 2010)

Hi Woodnthings

Thanks for the advice and the prompt reply. I will ground the collector but driving in a spike is not really an option. I have two alternatives i) A ground wire fixed to a shield anchor (expanding bolt) drilled into the concrete floor. ii) Ground wire back to the ground bar in the electrical fuse box. Are either likely to be as effective as a spike. Regards Keith


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## Longknife (Oct 25, 2010)

I don't understand at all the need for grounding the enclosure? I assume that your electrical connection is grounded - in that case you have all the grounding you'll need.
BTW I haven't fully understood your concept that sounded interesting. Pics would be nice :yes:


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## MuzzleMike (Jan 14, 2010)

Longknife said:


> I don't understand at all the need for grounding the enclosure? I assume that your electrical connection is grounded - in that case you have all the grounding you'll need.
> BTW I haven't fully understood your concept that sounded interesting. Pics would be nice :yes:



I under stand what He is saying I use to live in a Mobile home and if the out side of the home was not grounded you could get a jolt by just touching the out side of it . I would just use the common ground that comes from the fuse box and tie into it . 

Mike


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## GeorgeC (Jul 30, 2008)

Keith Biggin said:


> Hi Woodnthings
> 
> Thanks for the advice and the prompt reply. I will ground the collector but driving in a spike is not really an option. I have two alternatives i) A ground wire fixed to a shield anchor (expanding bolt) drilled into the concrete floor. ii) Ground wire back to the ground bar in the electrical fuse box. Are either likely to be as effective as a spike. Regards Keith


I would not consider the concrete floor a good ground. There many reasons for this. If you really have a static potential problem that needs grounding and do not have access to the outside earth then you should contact your local elictrical company.

They can advise you if their system is appropriate for use as a grounding point.

George


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