# Earthing Dust Extraction Pipes



## Bigbadmarky (29 Jul 2020)

Bonjour All, 
I've got a small dust extraction system running under one of my benches in my workshop and I'm quite please with it to be honest. I used 68mm downpipe for most of it with a cut up bike innertube holding it together. I even managed a few blast gates from MDF. While it does get blocked from time to time, its does a pretty decent job. The only downside is the static. I've been shocked more times than than a priest in strip club. 

How do I go about earthing it? Do I need to run copper inside the pipes? Where do I earth it to (FYI I don't have 240v in the workshop yet)?
Many thanks, 
BBM


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## sunnybob (29 Jul 2020)

How is the pipe fixed to the wall?
Assuming its a brick or cement wall and If you use metal pipe clips, just put wide washers between the clip and the wall. Bear in mind that all wall plugs are plastic and will insulate the screw.

Thats all you need. a metal bond between the outside of the pipe and either a brick wall, or a metal rod hammered into the ground. 
But every rubber joint is an insulator, so you will need to run a wire from piece to piece or earth each section seperately.


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## Rorschach (29 Jul 2020)

Aluminium flashing tape on the outside of the pipe works well.

Where to earth it could be the issue though, where is your power coming from at the moment?


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## MikeG. (29 Jul 2020)

Bigbadmarky":1zehw32o said:


> .......I've got a small dust extraction system.........(FYI I don't have 240v in the workshop yet).......



This has me confused. Have you got a child or small dog running in a ferris wheel to power your extractor? :lol:


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## Rorschach (29 Jul 2020)

MikeG.":3n3a37d6 said:


> Bigbadmarky":3n3a37d6 said:
> 
> 
> > .......I've got a small dust extraction system.........(FYI I don't have 240v in the workshop yet).......
> ...



I'm gonna blow your mind here Mike, there are these called extension cords that can run from one place to another. But if your extension cord isn't long enough then they make these amazing portable things called generators that will create power literally anywhere.

Rumour has it they are working on something called a Battery? Who knows if that will ever take off though.


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## Bm101 (29 Jul 2020)

MikeG.":3j7y9xb0 said:


> Bigbadmarky":3j7y9xb0 said:
> 
> 
> > .......I've got a small dust extraction system.........(FYI I don't have 240v in the workshop yet).......
> ...



Ah. The well known Vernepator Cur. 
An actual breed of dog at one time. 
Just when you thought you knew about dog breeds. 
And I quote: 'To train the dog to run faster, a glowing coal was thrown into the wheel, Bondeson adds.'
We have it tough these days eh?
https://www.npr.org/sections/thesalt/20 ... epator-cur


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## Trevanion (29 Jul 2020)

Rorschach":1l6bx3el said:


> I'm gonna blow your mind here Mike, there are these called extension cords...



Extension Cords... Cords!? In this here land of Her Majesty, we call them extension *LEADS*.


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## Bigbadmarky (29 Jul 2020)

Rorschach":2tnjq7uy said:


> MikeG.":2tnjq7uy said:
> 
> 
> > Bigbadmarky":2tnjq7uy said:
> ...



This is not far off the mark:
Lights, radio and some small stuff runs of a leisure battery charged from my solar panel. I drag an extension down from the house for everything else. If that fails I've got an exuberant toddler and a hamster wheel.

The pipes are fixed to the underside of the work bench and are completely isolated from the wall (plastic mounting clips + timber work bench). 
I'm guessing I'll have to run some kind of earth wire along the length of the pipe (outside) and attach it to the brick wall of the workshop. Would that suffice? Any particular considerations of where I should connect it to i.e. below the dpc?


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## Rorschach (29 Jul 2020)

Since you are presumably running the dust extractor using the extension cord/lead/wire/rope/ribbon/string/gimp/thread (i ran out of ideas here)
then you can use the earth on that.


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## Bigbadmarky (29 Jul 2020)

Rorschach":22qo5eat said:


> Since you are presumably running the dust extractor using the extension cord/lead/wire/rope/ribbon/string/gimp/thread (i ran out of ideas here)
> then you can use the earth on that.



Extension lead is a sealed unit and I'd be loathed to break it open for my half baked attempt at earthing the static. I'd rather have a fixed earth point (until I get 240v sorted down there).


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## Rorschach (29 Jul 2020)

Bigbadmarky":3cf84hjr said:


> Rorschach":3cf84hjr said:
> 
> 
> > Since you are presumably running the dust extractor using the extension cord/lead/wire/rope/ribbon/string/gimp/thread (i ran out of ideas here)
> ...



You don't need to break it open.

The hack way would be to simple wrap a thin wire around the earth pin of the plug on the vacuum. A neater way would be to take a spare plug and wire the earth from that onto a wire and attach that to your pipes.


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## Bigbadmarky (29 Jul 2020)

Rorschach":26qm4egc said:


> Bigbadmarky":26qm4egc said:
> 
> 
> > Rorschach":26qm4egc said:
> ...



Cracking idea. Thanks for that.


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## Lons (29 Jul 2020)

Bigbadmarky":1i2jg09d said:


> Rorschach":1i2jg09d said:
> 
> 
> > The hack way would be to simple wrap a thin wire around the earth pin of the plug on the vacuum. A neater way would be to take a spare plug and wire the earth from that onto a wire and attach that to your pipes.
> ...



*Please don't wrap a wire around the earth pin of the vac * :roll: 
Imagine, you trip over the lead reach out and grab the duct to break your fall and get a rather nasty shock because the thin wire has slipped across the live as the plug has been pulled. Not sensible advice at all!


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## Rorschach (29 Jul 2020)

Lons":2aqd1r4d said:


> *Please don't wrap a wire around the earth pin of the vac * :roll:
> Imagine, you trip over the lead reach out and grab the duct to break your fall and get a rather nasty shock because the thin wire has slipped across the live as the plug has been pulled. Not sensible advice at all!



I did say it was the hack way, which is rarely the safe way to do things. That being said, the circumstances required for your scenario to happen are very remote, requiring you to be suitably earthed at the exact moment the wire brushes against the live pin while being ripped out. But of course as you know it's basically impossible for the live pin on the plug to be exposed while live.


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## Lons (29 Jul 2020)

Rorschach":26r867ow said:


> I did say it was the hack way, which is rarely the safe way to do things. That being said, the circumstances required for your scenario to happen are very remote, requiring you to be suitably earthed at the exact moment the wire brushes against the live pin while being ripped out. But of course as you know it's basically impossible for the live pin on the plug to be exposed while live.


Hack is exactly what it is and as you well know nothing's impossible. If that's the way you want to do things, and it explains rather a lot about you then it's your choice but IMO you really shouldn't be advising others on a open forum especially as it's highly unlikely you know the OPs level of competence or circumstances and even worse you don't know who else is reading your posts.

I've no intention of letting you develop yet another of your pathetic arguments so will just leave it to others to judge for themselves.

EDIT: Anyway what happened to your pledge not to reply to my posts? :wink:


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## Rorschach (29 Jul 2020)

Lons":16jocklp said:


> EDIT: Anyway what happened to your pledge not to reply to my posts? :wink:



I'll make exceptions to point out your lack of knowledge on plugs :wink: 

Anyway the reply wasn't so much for your benefit, it was for the OP.


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## mindthatwhatouch (29 Jul 2020)

Don’t go messing about with a 13amp plug and trying to wrap something round the earth pin.

Take a piece of copper wire (or aluminium tape) wrap it around the pipe and earth it, wherever is easiest. Behind a washer screwed into the brick work, a bit of exposed metalwork any where (metal strap) or a piece of metal buried in the ground. Earthing it at two or three points then even better.


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## Lons (29 Jul 2020)

Rorschach":22as1dly said:


> Lons":22as1dly said:
> 
> 
> > EDIT: Anyway what happened to your pledge not to reply to my posts? :wink:
> ...


OK I'll make an exception as well to say that you have absolutely no idea of my level of competence on electrical wiring so it's another of your know it all assumptions. Anyone who suggests wrapping a wire around a pin on the plug of a vac has a screw loose somewhere, what's your next little tip, silver paper around a blown fuse? :wink: 

I'll end my participation in this argument with the observation that in Jeremy Clarkson's words " you must be very well endowed to be such a huge pr+ck" :twisted:


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## Rorschach (29 Jul 2020)

There is a purpose made device if you go the non hack route (which you should really)

As you can see though, making your own from a spare plug would be very easy, just remove the live and neutral pins and wire only to the earth.


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## Daniel2 (29 Jul 2020)

Hi,
With all due respect, if your knowledge of electricty is really that low (meant in the kindest possible manner, none of us can know everything about everything), I would strongly recommend you getting someone around who knows what they are doing.
Even if it's only a mate, so to speak.
It's one thing to play around with hacks and bodged systems if one has some inkling of what one is doing. It's quite another animal if you don't. Personal safety, that of others and fire risks should not be underestimated.
Any earth is there primarily for safety. Akin to fixing up a safety net, yet clueless about knot tying.
Please don't be another statistic, and enjoy your workshop safely.
Sorry for the preaching, but you're running a high risk.

All the best,
Daniel


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## RogerS (29 Jul 2020)

Daniel2":18jdxhxb said:


> Hi,
> With all due respect, if your knowledge of electricty is really that low (meant in the kindest possible manner, none of us can know everything about everything), I would strongly recommend you getting someone around who knows what they are doing.
> .....
> All the best,
> Daniel



Bang on, Daniel...you've sussed out Rorschach very quickly. =D>


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## Bigbadmarky (30 Jul 2020)

I appreciate all your replies and the concern raised on my behalf. 
Contrary to popular opinion (my wife's included), I'm not a silly person. I wasn't planning on bodging an earth via the extension. I was merely trying to be polite to the chap and grateful for his suggestion. My primary rule in DIY is I'll have a crack at anything but won't touch electrics or gas. Following said rule has seen me through 38 years and will hopefully keep me going for a bit longer. 

I found a couple of videos on Youtube which were useful and informative. This one my John McGrath was particularly useful https://youtu.be/812Ez9OT0As. 

My shop vac is in a fixed location so it would make much more sense for me to have a fixed earth point somewhere in its vicinity. I think I might try and run a copper wire through the pipe and aluminium foil tape round the outside and earth it to the garage wall as suggested. Hopefully that will discharge static from the inside and out of the pipes and save my sanity. 

Thanks for all the replies. 
Peace out, 
BBM


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## sunnybob (30 Jul 2020)

Foil tape can be hit and miss as far as electrical conductivity is concerned. Bear in mind the the foil is fixed to the pipe with a layer of goo. If the goo is thick, its an insulator. If its old and dry, then it most likely will conduct.
You would normally get a circuit, but I wouldnt guarantee a circuit using just that. Bare copper wire is foolproof, just make sure your connection to a ground is also foolproof.
If you have any concerns about using the mains earth, Its quite acceptable to just beat a length of iron rebar into the ground near your installation (at least a foot deep, deeper is better), and then connect your earthing strap to that.


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## Rorschach (30 Jul 2020)

sunnybob":3d080fg7 said:


> Foil tape can be hit and miss as far as electrical conductivity is concerned. Bear in mind the the foil is fixed to the pipe with a layer of goo. If the goo is thick, its an insulator. If its old and dry, then it most likely will conduct.
> You would normally get a circuit, but I wouldnt guarantee a circuit using just that. Bare copper wire is foolproof, just make sure your connection to a ground is also foolproof.
> If you have any concerns about using the mains earth, Its quite acceptable to just beat a length of iron rebar into the ground near your installation (at least a foot deep, deeper is better), and then connect your earthing strap to that.



Insulation from the adhesive is negligible and with foil tape you have the benefit of surface area as opposed to a thin bare copper wire. We are not talking about conducting a current in the say way as wiring up some lights for example, we are providing a path for the static to leak away, after all it is building up in PVC pipe, PVC itself used as an electrical insulator.

Edit: Forgot to add, if the OP is getting a shock from a certain location, say the top of the pipe next to his sander, then if that area is covered in the earthed foil tape it would be literally impossible to get a shock there again, even if the adhesive was providing insulation.


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## Bigbadmarky (30 Jul 2020)

Thanks for the advice chaps. Much appreciated. 
I might use foil tape to stick down some bare copper wire on the outside of the pipe. Belt and braces approach!
Thanks again, 
BBM


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## Lons (30 Jul 2020)

Bigbadmarky":3hmw7onj said:


> I appreciate all your replies and the concern raised on my behalf.
> Contrary to popular opinion (my wife's included), I'm not a silly person. I wasn't planning on bodging an earth via the extension. I was merely trying to be polite to the chap and grateful for his suggestion.
> BBM



Absolutely the right decision BBM you're clearly very sensible but there's no need to be polite to someone who suggests a practice that's unsafe. While you have the sense to ignore it unfortunately none of us know how many others who lack that common sense and basic knowledge are browsing the forum and think it might be a good idea.

We all have a responsibility to not post potentially dangerous practice, better to post nothing at all than suggest someone wraps copper wire around the earth pin on a plug. There are people out there who don't even know which pin is which for heavens sake.

Bob's suggestion you wack a length of metal earthing rod into the ground is sound advice.
Stay safe.


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## gregmcateer (30 Jul 2020)

Good people, 
If I may jump in with a diameter question that's indirectly related. 
I'm planning to get a DE and pipe it. Just a bandsaw and lathe next to each other. Should get 125 or 150mm, or will 100mm be enough?
TIA
Greg


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## sunnybob (30 Jul 2020)

Depends entirely on your motor. No point having an oversized pipe and an undersized motor, nothing will move.
Every extractor unit will come with the recommended pipe for that size.As a general rule, bigger is better.


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## gregmcateer (30 Jul 2020)

Thanks, Bob
I am thinking 2 or 3hp. Was wondering if 3 hp is overkill for say 4 metres ducting, or is it still worth it to shift dust quickly? Filter obviously still required, and planned


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## sunnybob (31 Jul 2020)

If money is not too much of an issue, then your next question is "am I going to get more machines"?
A smallish bandsaw and lathe will work on 100 mm and maybe 1 hp fine, but if you are planning on adding a planer or thicknesser, then you need a much bigger motor and pipe.
Its a "piece of string" question to be honest. Do you want operating room clean? or are you happy with some dust escaping the system?
But if you are of a technical nature then you can study the BILL PENTZ web site and scientifically work out every aspect of your system. Be warned, its a very technical work. :shock:


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## gregmcateer (31 Jul 2020)

Cheers, Bob. 
I think that probably answers it. 
No plans, likelihood or space for any other 'big' machines. I've been on the Pentz site and it's mostly way over my head - big picture clear, detail not at all. 
I guess I need to price up 100mm and a 1 - 2 HP extractor with a proper fine filter on top. If it's not too big a number, look at larger duct for efficiency. 
Thanks again. 
Greg


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## sunnybob (31 Jul 2020)

I'm hands on technical, and can follow any diagram, but that site just has too much info :roll: :lol: 

But think long about upgrades and additions. I've been doing this woodworking lark for only 6 years and I've completely re arranged my single car garage at least three times to make room for more equipment. 8) 
I could have saved myself many hundreds if I'd known then what I know now.  :shock:


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## gregmcateer (31 Jul 2020)

That's a good shout!
I will think long and hard and I'll buy the best I can reasonably afford (And get past SWMBO!!)
Cheers
Greg


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## Lons (31 Jul 2020)

sunnybob":2lh1aksu said:


> I've been doing this woodworking lark for only 6 years and I've completely re arranged my single car garage at least three times to make room for more equipment. 8)
> I could have saved myself many hundreds if I'd known then what I know now.  :shock:


What!!! Only 3 times in 6 years :roll: what are you doing Bob mine is constantly evolving. #-o


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## sunnybob (31 Jul 2020)

Lons, the active ingredient there was "COMPLETELY" rearranged.
Minor weekly shuffles dont count :roll: :lol: :lol: :lol:


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## gregmcateer (31 Jul 2020)

I'm loving all this- and I hope learning, too! Trouble is, it is clear a little knowledge is a dangerous thing!

If I went with a 2 or 3 HP extractor with a 125mm duct, is this worth it as the bandsaw only has 100mm port? (Lathe can have 125 from source).

And second question, blast gates near source, or near extractor?

Thanks again

Greg


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## Inspector (31 Jul 2020)

Most 3hp DC's have the same impeller and housing as a 2hp DC. Usually about 300mm. The reason they flow more air is the extra filter allows more flow. Better 3hp DC's will have a 330mm or so impeller. If you get a 3hp use 150mm duct. When you get to the bandsaw you split the 150mm into three 100mm pipes. One to the lower blade guide area under the table, one to the bottom of the cabinet and the third just behind the upper blade guides above the table. Three 100mm pipes flow approximately the same air as a 150mm duct. 

Blast gates are best located at the main trunk where the branches come to join. If the extractor has a 2 or 3 way splitter at the inlet get rid of it. It creates a lot of turbulence at the impeller. Better is a large pipe straight to it for several feet with wyes to branch off to other machines.

Lathe benefits from as much air as it can get. so use a 150mm duct all the way to it. A bellmouth hood provides the best flow into the duct so will capture fine dust further than from a pipe without.

Pete


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## gregmcateer (31 Jul 2020)

Inspector Pete, 
That's really clear advice, thankyou.
Am I correct thinking a circular bell mouth good is better than a rectangular one?
TIA
Greg


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## Inspector (31 Jul 2020)

Round bell mouth to a hose/pipe is as good as you can get. 
If by rectangular you mean a square duct with the four sides flared with the same radii it will be pretty good too.
If by rectangular you mean the flared cone shapes like a Big Gulp type the bell mouth is better.

I've linked this before but the gent is using a 6" duct on a 3 ph DC. https://www.youtube.com/watch?v=xjtHCmR-N3M

Pete


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## gregmcateer (31 Jul 2020)

Wow! That's some suck power!

I'll keep searching, but haven't found anywhere here that seems to sell the round bell mouth. Maybe worth trying a local fabricator, as I live in the original Black Country :lol: 

Thanks again - much appreciated


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## Inspector (31 Jul 2020)

Guys that make their own speakers use them. Try speaker ports. 150mm are hard to come by but are out there. The Aussie forum shows how to make them by heating PVC on a form in the lathe. Later when I have time I can link it to you if you want. Or do like that one and turn it from MDF or wood on your lathe.

Pete


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## Lons (31 Jul 2020)

sunnybob":1astw3yg said:


> Lons, the active ingredient there was "COMPLETELY" rearranged.
> Minor weekly shuffles dont count :roll: :lol: :lol: :lol:


   My shuffles are major events Bob and being in the UK it's guaranteed that as soon as all my stuff is outside the heavens open.


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## gregmcateer (31 Jul 2020)

Google and perseverance are my friends;

www.ductstore.co.uk/acatalog/Bell-Mouths.html#aBM

I know nothing of the firm, so all usual disclaimers apply  



Inspector":o7mq959q said:


> Guys that make their own speakers use them. Try speaker ports. 150mm are hard to come by but are out there. The Aussie forum shows how to make them by heating PVC on a form in the lathe. Later when I have time I can link it to you if you want. Or do like that one and turn it from MDF or wood on your lathe.
> 
> Pete


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## Inspector (31 Jul 2020)

It is more of a cone rather than a bell mouth but still better than a naked duct.

Pete


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