ESD mats - when is grounding not required?

[steaky1212]

Hi all,

I've been having a disagreement with someone at work about whether or not some ESD floor matting needs attaching to a ground point, and was hoping some collective wisdom would shed some light one way or another.

- His view is that connecting to ground is not required as it is so big that it should dissipate constantly.
- My view is that BSEN 61340-5-1 clearly states that flooring system needs to be attached to the common ground point. I've never heard of the argument of large mats not requiring grounding.

Is there a case that can be made, that says that if the matting is large enough then a connection to ground is not required?
I could probably use a flash tester to measure the resistance, but we are all in lockdown so it's very difficult for me to perform any sort of testing.

Other notes: The matting is on painted concrete floor - the floor paint isn't anything special. However, I did conduct some burn-in breakdown tests elsewhere in the factory (so may have had a different floor paint) and noticed some arcing to the floor - so maybe there is something there? I can't remember what values I was running through, but it was arcing from black nylon wheels so must've been fairly high.

Any insight is greatly appreciated, thanks.


EDIT: This is in a production environment where the electronics are installed inside the product next to a row of benches. It is impractical to use to use wristbands, so we have implemented matting/floor paint and footwear.

[Elasia]

double sided copper tape to whatever grounding point if you are in an industrial/commercial setting.. its cheap insurance

Thing is, its a risk control product.. not a guarantee you wont zap something, same reason you use the wrist guard when working on someone elses item

Now beyond that, i've never connected a floor mat to direct ground myself in my labs.. only time you even really need a floor mat is if carpet *or* like the above and you need to par down your risk on sensitive items

[wraper]

- His view is that connecting to ground is not required as it is so big that it should dissipate constantly.

So big that it might act as capacitor plate.

[thm_w]

- My view is that BSEN 61340-5-1 clearly states that flooring system needs to be attached to the common ground point. I've never heard of the argument of large mats not requiring grounding.

Well if you can quote from the spec and they cannot, then it sounds like you know what you are talking about.

This page says: "The EPA ground provides a low resistance path (<2 ) to ground, usually to mains protective earth. A single EPA ground must be used within one EPA facility. "
http://www.compliance-club.com/archive/old_archive/030923.htm

So question is what ground is, if its defined in the spec somewhere.
Maybe they just mean alternative to mains earth would be a grounded rod, pipe, etc.

[tooki]

Why not have proper ESD floor paint applied? That just needs one ground point, and then just equip everyone with ESD footwear and that’s all you need. (That’s how my workplace is set up.)

[thm_w]

Why not have proper ESD floor paint applied? That just needs one ground point, and then just equip everyone with ESD footwear and that’s all you need. (That’s how my workplace is set up.)

The point is the person he is arguing with says the ground point is not required.

[Gregg]

I think OP is being trolled.  Whenever the situation arises where some Dunning Kruger sufferer offers an opinion that must be true unless you can disprove it, you are being trolled.   

[steaky1212]

I think the main issue was that they are under the illusion that static dissapative means that it will dissipate static to the environment - and therefore a connection to ground is not required.

(side note, this is a tricky situation as I have butted heads with the same person before as I wanted to decommission a hipot tester that had sucked in metal dust, whereas he was fine blowing it through with an air-line).

[Mr. Scram]

I think OP is being trolled.  Whenever the situation arises where some Dunning Kruger sufferer offers an opinion that must be true unless you can disprove it, you are being trolled.   

Trolling is intentional while Dunning-Kruger by definition is not. I'm sorry to be a bit pedantic but it seems to be a trend to label any and all dissent as trolling.

[tooki]

I think OP is being trolled.  Whenever the situation arises where some Dunning Kruger sufferer offers an opinion that must be true unless you can disprove it, you are being trolled.   

Trolling is intentional while Dunning-Kruger by definition is not. I'm sorry to be a bit pedantic but it seems to be a trend to label any and all dissent as trolling.

1000% truth. It’s super annoying.

[tkamiya]

Concrete itself is somewhat conducting.  Rebar inside is grounded at some point.  So if it is painted with a proper conductive paint, it is grounded,.

[wraper]

Concrete itself is somewhat conducting.  Rebar inside is grounded at some point.  So if it is painted with a proper conductive paint, it is grounded,.

It's at potential you can only guess about and might not be the same as any equipment and other things connected to mains earth. The fact is, it might work OK but does not adhere to any standards and you might get screwed over legally/ losing customers say when business partner finds out or by physically damaging things.

[thm_w]

Concrete itself is somewhat conducting.  Rebar inside is grounded at some point.  So if it is painted with a proper conductive paint, it is grounded,.

Probably, but thats not what the spec requires.
Perhaps you can make that argument if you tie directly to the rebar.

[SparkyFX]

Is there a case that can be made, that says that if the matting is large enough then a connection to ground is not required?
I could probably use a flash tester to measure the resistance, but we are all in lockdown so it's very difficult for me to perform any sort of testing.

Testing is the best way to settle the discussion.

In my opinion both points of view have something to it, as in this is not an "either - or" question, but which effect dominates. But without grounding the floor mats the actual conductivity might depend on humidity and temperature in a way that might exceed acceptable limits. That might also influence how or when to test.

[tkamiya]

Use of rebar as electrical ground is called "reefer ground" and is approved by NEC.  It's perfectly legal substitute for ground rods. 

Now, just painting anti-static paint on that is approved or not, I have no idea. 

[jh15]

It is Ufer earthing or grounding method.

[tkamiya]

You are right!  I always mess this one up.  Appreciate your correction.

The point I wanted to make was, during construction, rebar can be welded and portion of it exposed.  ("inspectable" is a requirement for this type of ground)  In that case, it can be used as a ground for mains.

[SilverSolder]

Ufer madness? 

[DanielMilkov]

- His view is that connecting to ground is not required as it is so big that it should dissipate constantly.
- My view is that BSEN 61340-5-1 clearly states that flooring system needs to be attached to the common ground point. I've never heard of the argument of large mats not requiring grounding.

If you are working with sensitive devices its always a good idea to ground the whole mat just in case becouse dust/residue on the surface could compromise its electrical properties.You can also attenuate its properties by dragging heavy objects over the surface, abrasion or cuts, chemical cleaners, or direct heat caused by soldering or rework.I personally always keep my matt grounded and wear a wrist strap only in extreme cases.But overall these wrist straps are a big pain.And i avoid them as often as i can.But I always keep my matt grounded just in case I work on something more sensitive.

You can read the artical here : https://blog.gotopac.com/2017/09/06/do-you-need-a-esd-worksurface-mat-if-your-workstation-has-esd-laminate-do-you-need-an-esd-chair-if-you-have-an-esd-floormat/