Re: [PSES] Earthing -- Star vs Spring/Split Washers

2022-02-16 Thread Charles Grasso 
I am sure our military folks have run across this issue before! Perhaps you
can look into some of the publicly available documents ??

On Tue, Feb 15, 2022 at 5:54 PM Richard Nute  wrote:

> * This message originated outside of DISH and was sent by: ri...@ieee.org
>  *
> --
>
>
>
> Hello James:
>
>
>
> As for resistance of the connection, I doubt that there is significant
> difference.  I have tested both with a high-current-sourcing milliohmeter.
> You can repeat the test and see if there is a difference in the
> resistance.  (Even a loose connection will still pass the high current
> test.)
>
>
>
> A star washer is more likely to penetrate paint.  However, a stud mounted
> in a panel is independent of paint.  So, a lockwasher simply locks the nut
> to the stud and has little to no effect on the resistance of the
> connection.
>
>
>
> Best regards,
>
> Rich
>
>
>
>
>
>
>
> *From:* James Pawson (U3C) 
> *Sent:* Tuesday, February 15, 2022 7:34 AM
> *To:* EMC-PSTC@LISTSERV.IEEE.ORG
> *Subject:* [PSES] Earthing -- Star vs Spring/Split Washers
>
>
>
> Hello all,
>
>
>
> I’ve given myself a regular internet headache trying to understand the
> relative merits of spring vs star washers for use on an earth stud for
> protective earthing purposes.
>
>
>
> What is the conventional wisdom and justification? I know I can trust you
> folks to be above a simple “we’ve always done it this way”
>
>
>
> Can anyone point me towards any citable references or standards covering
> this subject?
>
>
>
> I promise I will write a blog post to pull the information together for
> future confused generations.
>
>
>
> Thanks and all the best,
>
> James
>
>
>
>
>
> James Pawson
>
> The EMC Problem Solver
>
>
>
> *Unit 3 Compliance Ltd*
>
> *EMC : Environmental & Vibration : Electrical Safety : CE & UKCA :
> Consultancy*
>
>
>
> www.unit3compliance.co.uk
> <http://www.unit3compliance.co.uk/>
> |  ja...@unit3compliance.co.uk
>
> +44(0)1274 911747  |  +44(0)7811 139957
>
> 2 Wellington Business Park, New Lane, Bradford, BD4 8AL
>
> Registered in England and Wales # 10574298
>
>
>
>
>
>
> -
> 
>
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-- 

Charles Grasso

Dish Technologies

 (c) 303-204-2974

(h) 303-317-5530

(e ) charles.gra...@dish.com

(e2) chasgra...@gmail.com

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Re: [PSES] Earthing -- Star vs Spring/Split Washers

2022-02-15 Thread Richard Nute 
 

Hello James:

 

As for resistance of the connection, I doubt that there is significant
difference.  I have tested both with a high-current-sourcing milliohmeter.
You can repeat the test and see if there is a difference in the resistance.
(Even a loose connection will still pass the high current test.)

 

A star washer is more likely to penetrate paint.  However, a stud mounted in
a panel is independent of paint.  So, a lockwasher simply locks the nut to
the stud and has little to no effect on the resistance of the connection.  

 

Best regards,

Rich

 

 

 

From: James Pawson (U3C)  
Sent: Tuesday, February 15, 2022 7:34 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Earthing -- Star vs Spring/Split Washers

 

Hello all,

 

I've given myself a regular internet headache trying to understand the
relative merits of spring vs star washers for use on an earth stud for
protective earthing purposes.

 

What is the conventional wisdom and justification? I know I can trust you
folks to be above a simple "we've always done it this way"

 

Can anyone point me towards any citable references or standards covering
this subject?

 

I promise I will write a blog post to pull the information together for
future confused generations.

 

Thanks and all the best,

James

 

 

James Pawson

The EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA :
Consultancy

 

 <http://www.unit3compliance.co.uk/> www.unit3compliance.co.uk  |
<mailto:ja...@unit3compliance.co.uk> ja...@unit3compliance.co.uk 

+44(0)1274 911747  |  +44(0)7811 139957

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298

 

 

 


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Re: [PSES] Earthing -- Star vs Spring/Split Washers

2022-02-15 Thread Doug Nix 
James,

If your concerns are above 60 Hz, i.e., you’re thinking about HF bonding as 
well as LF bonding for safety, then I have two excellent resources for you:

[1] T. Williams, K. Armstrong, EMC for Systems and Installations, 1st Ed. 
Oxford: Newnes. 2000. ISBN 0 7506 4167 3

[2] E.B. Joffe, K. Lock, Grounds for Grounding, 1st ed. Hoboken: Wiley & Sons. 
2010. ISBN 978-0471-66008-8

Both books are very good. In [1], have a look at p.121-122. In [2], have a look 
at p.335-336. Actually, Chapter 5 on bonding, starting at p. 323, is excellent.

I could recommend others, but I think those two are a great start.

Doug Nix
d...@ieee.org
+1 (519) 729-5704

> On 15-Feb-22, at 14:48, Douglas E Powell  wrote:
> 
> James,
> 
> Most safety standards have requirements for ground bond testing based on the 
> current available in the hazard. I've never seen requirements specifying the 
> type of washer other than it cannot have compressible material in the stack 
> up, as polymers or fiber washers.
> 
> Back in the day, I learned my earthing (EU) or grounding (US) for high power 
> equipment from a German expert at LGA Landesgewerbeanstalt Bayern in Nürnberg 
> and the guidance I received was to use star washers on plain metal surfaces; 
> not to cut through paint as many believe, but to dig into the metal parts to 
> provide an oxygen free connection. Yes, initial conductivity for a steel star 
> washer is not great, but the EU Liability Directive would indicate that the 
> connection needs to be reliable for up to 10 years. For a normally very low 
> current (mA) ground to launch into service at a moment's notice, and safely 
> carry away a few hundred amps, is sometimes a challenge if the long term 
> environment is in the least bit corrosive.
> 
> Notably, my mentor also allowed serrated lock washers.
> 
> Best,  Doug
> 
> Douglas E Powell
> Laporte, Colorado USA
> LinkedIn 
> 
> (UTC -07:00) Mountain Time (US-MST)
> 
> 
> 
> On Tue, Feb 15, 2022 at 8:34 AM James Pawson (U3C) 
> mailto:ja...@unit3compliance.co.uk>> wrote:
> Hello all,
> 
> 
> 
> I’ve given myself a regular internet headache trying to understand the 
> relative merits of spring vs star washers for use on an earth stud for 
> protective earthing purposes.
> 
> 
> 
> What is the conventional wisdom and justification? I know I can trust you 
> folks to be above a simple “we’ve always done it this way”
> 
> 
> 
> Can anyone point me towards any citable references or standards covering this 
> subject?
> 
> 
> 
> I promise I will write a blog post to pull the information together for 
> future confused generations.
> 
> 
> 
> Thanks and all the best,
> 
> James
> 
> 
> 
> 
> 
> James Pawson
> 
> The EMC Problem Solver
> 
> 
> 
> Unit 3 Compliance Ltd
> 
> EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy
> 
> 
> 
> www.unit3compliance.co.uk   |  
> ja...@unit3compliance.co.uk 
> +44(0)1274 911747  |  +44(0)7811 139957
> 
> 2 Wellington Business Park, New Lane, Bradford, BD4 8AL
> 
> Registered in England and Wales # 10574298
> 
> 
> 
> 
> 
> 
> 
> 
> 
>  
> This email has been checked for viruses by AVG antivirus software.
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> 
> This message is from the IEEE Product Safety Engineering Society emc-pstc 
> discussion list. To post a message to the list, send your e-mail to 
> >
> 
> All emc-pstc postings are archived and searchable on the web at: 
> http://www.ieee-pses.org/emc-pstc.html 
> 
> Attachments are not permitted but the IEEE PSES Online Communities site at 
> http://product-compliance.oc.ieee.org/ 
>  can be used for graphics (in 
> well-used formats), large files, etc.
> 
> Website:  http://www.ieee-pses.org/ 
> Instructions:  http://www.ieee-pses.org/list.html (including how to 
> unsubscribe) 
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> This message is from the IEEE Product Safety Engineering Society emc-pstc 
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Re: [PSES] Earthing -- Star vs Spring/Split Washers

2022-02-15 Thread Douglas E Powell 
James,

Most safety standards have requirements for ground bond testing based on
the current available in the hazard. I've never seen
requirements specifying the type of washer other than it cannot have
compressible material in the stack up, as polymers or fiber washers.

Back in the day, I learned my earthing (EU) or grounding (US) for high
power equipment from a German expert at LGA Landesgewerbeanstalt Bayern in
Nürnberg and the guidance I received was to use star washers on plain metal
surfaces; not to cut through paint as many believe, but to dig into the
metal parts to provide an oxygen free connection. Yes, initial conductivity
for a steel star washer is not great, but the EU Liability Directive would
indicate that the connection needs to be reliable for up to 10 years. For a
normally very low current (mA) ground to launch into service at a moment's
notice, and safely carry away a few hundred amps, is sometimes a challenge
if the long term environment is in the least bit corrosive.

Notably, my mentor also allowed serrated lock washers.

Best,  Doug

Douglas E Powell
Laporte, Colorado USA
LinkedIn 

(UTC -07:00) Mountain Time (US-MST)



On Tue, Feb 15, 2022 at 8:34 AM James Pawson (U3C) <
ja...@unit3compliance.co.uk> wrote:

> Hello all,
>
>
>
> I’ve given myself a regular internet headache trying to understand the
> relative merits of spring vs star washers for use on an earth stud for
> protective earthing purposes.
>
>
>
> What is the conventional wisdom and justification? I know I can trust you
> folks to be above a simple “we’ve always done it this way”
>
>
>
> Can anyone point me towards any citable references or standards covering
> this subject?
>
>
>
> I promise I will write a blog post to pull the information together for
> future confused generations.
>
>
>
> Thanks and all the best,
>
> James
>
>
>
>
>
> James Pawson
>
> The EMC Problem Solver
>
>
>
> *Unit 3 Compliance Ltd*
>
> *EMC : Environmental & Vibration : Electrical Safety : CE & UKCA :
> Consultancy*
>
>
>
> www.unit3compliance.co.uk  |  ja...@unit3compliance.co.uk
>
> +44(0)1274 911747  |  +44(0)7811 139957
>
> 2 Wellington Business Park, New Lane, Bradford, BD4 8AL
>
> Registered in England and Wales # 10574298
>
>
>
>
>
>
>
>
> --
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> This email has been checked for viruses by AVG antivirus software.
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> 
>
> This message is from the IEEE Product Safety Engineering Society emc-pstc
> discussion list. To post a message to the list, send your e-mail to <
> emc-p...@ieee.org>
>
> All emc-pstc postings are archived and searchable on the web at:
> http://www.ieee-pses.org/emc-pstc.html
>
> Attachments are not permitted but the IEEE PSES Online Communities site at
> http://product-compliance.oc.ieee.org/ can be used for graphics (in
> well-used formats), large files, etc.
>
> Website: http://www.ieee-pses.org/
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> unsubscribe) 
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> For help, send mail to the list administrators:
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> Mike Cantwell 
>
> For policy questions, send mail to:
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> David Heald 
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All emc-pstc postings are archived and searchable on the web at:
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Attachments are not permitted but the IEEE PSES Online Communities site at 
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formats), large files, etc.

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[PSES] Earthing -- Star vs Spring/Split Washers

2022-02-15 Thread James Pawson (U3C) 
Hello all,

 

I've given myself a regular internet headache trying to understand the
relative merits of spring vs star washers for use on an earth stud for
protective earthing purposes.

 

What is the conventional wisdom and justification? I know I can trust you
folks to be above a simple "we've always done it this way"

 

Can anyone point me towards any citable references or standards covering
this subject?

 

I promise I will write a blog post to pull the information together for
future confused generations.

 

Thanks and all the best,

James

 

 

James Pawson

The EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA :
Consultancy

 

  www.unit3compliance.co.uk  |
 ja...@unit3compliance.co.uk 

+44(0)1274 911747  |  +44(0)7811 139957

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298

 

 

 



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