Re: [PSES] Chamber grounding [General Use]

[ce-test, qualified testing bv, Gert Gremmen]

>Yes, the building ground is likely to be noisy, unless you actually connect
directly >back to its earth spike

No signal, ground or supply is noisy. It is the designer that defines a
certain conductor to be clean, and references all other voltages (probably
to be filtered)  to that potential.
Inside a screened room, there is only ONE ground (reference potential), and
that is the conductive shell around the EUT (so the chamber wall itself). 

Electrical safety inside a room must be referenced to that potential, as
well as all signals measured inside. 
All cable screens are therefore connected to the conductive wall before
leaving. It is  fully irrelevant to what you connect  the outside of the
chamber , as the skin effect effectively separates all current on the
external surface from the internal surface. For extremely low frequencies,
wall thickness may be insufficient, and wall current on the external
surface can show up on the internal surface and create potential differences
on different parts of the internal wall (and possibly fields inside). The
only remedy is increasing wall thickness , dual walls,  increase
conductivity or apply a layer of  magnetic conductive shield (ferro metal Ur
> 1) .
One should prevent LF current to flow on the outside. Still it makes no
difference to what ground point you connect the room (just do not make 2
different connections).
One last problem may be the presence of LF magnetic fields on the outside,
they may create currents op to several amps on the outside surface, leading
to the problem sketched above.  (try connecting a 50-60Hz current clamp
around the metal tubing of your central heating and be surprised: the loops
in these tubes and the mains magnetic field easily creates  a few amps of
"thougth" ground faults)  .

Electrical safety at the outside of the room is obtained by simply
connecting the wall to the building's safety conductor.  

Gert

-Original Message-
From: John Woodgate [mailto:jmw1...@btinternet.com] 
Sent: Wednesday 19 July 2017 09:31
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]

It's not my consensus! Yes, the building ground is likely to be noisy,
unless you actually connect directly back to its earth spike. Even then, the
wire you use is an inductor and may have noise induced in it. 

I am quite sure that BS 7671 and other Code standards do not recognize that
a screened room is outside their scopes. 

With best wishes DESIGN IT IN! OOO - Own Opinions Only www.jmwa.demon.co.uk
J M Woodgate and Associates Rayleigh England

Sylvae in aeternum manent.

-Original Message-
From: Price, Andrew (Leonardo, UK)
[mailto:andrew.p.pr...@leonardocompany.com]
Sent: 19 July 2017 07:16
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]

Thanks all for the replies.

It seems that there is some divided opinion.

Some of the test houses I have spoken to state that they definitely ground
their chambers via ground spikes. This is to remove low frequency noise that
causes issues with the low frequency emc tests  that are required in
mil-std, def stan  and rtca/do-160.
One test house I spoke to stated that as a result of cost cutting an earth
spike was not fitted so earthing was taken to building ground, as a result
of this the test house has issues with low frequency noise.

The consensus of the forum is that a ground spike should not be required and
the building ground used should be enough.

This then probably raises the question of how good is the building ground?
Is there a requirement for this?
If there is noise on the building ground how can this be eliminated?

Regards
Andy



 Andrew Price
 Land & Naval Defence Electronics Division
 Prinicpal Environmental Engineer (EMC)

 Leonardo MW Ltd
 Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
 Tel  EMC LAB : +44 (0)1268 883308
 Mobile: +44 (0)7507 854888
 
andrew.p.pr...@leonardocompany.com<mailto:andrew.p.pr...@leonardocompany.com
>
 leonardocomapany.com
HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS /
SPACE

* Please consider the environment before printing this email.




Leonardo MW Ltd
Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex
SS14 3EL A company registered in England & Wales.  Company no. 02426132

This email and any attachments are confidential to the intended recipient
and may also be privileged. If you are not the intended recipient please
delete it from your system and notify the sender.
You should not copy it or use it for any purpose nor disclose or distribute
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-

This message is from the IEEE 

Re: [PSES] Chamber grounding [General Use]

[ce-test, qualified testing bv, Gert Gremmen]

>I am quite sure that BS 7671 and other Code standards do not recognize that
a >screened room is outside their scopes

Of course they won't. But it is, technically.

Gert

-Original Message-
From: John Woodgate [mailto:jmw1...@btinternet.com] 
Sent: Wednesday 19 July 2017 09:31
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]

It's not my consensus! Yes, the building ground is likely to be noisy,
unless you actually connect directly back to its earth spike. Even then, the
wire you use is an inductor and may have noise induced in it. 

I am quite sure that BS 7671 and other Code standards do not recognize that
a screened room is outside their scopes. 

With best wishes DESIGN IT IN! OOO - Own Opinions Only www.jmwa.demon.co.uk
J M Woodgate and Associates Rayleigh England

Sylvae in aeternum manent.

-Original Message-
From: Price, Andrew (Leonardo, UK)
[mailto:andrew.p.pr...@leonardocompany.com]
Sent: 19 July 2017 07:16
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]

Thanks all for the replies.

It seems that there is some divided opinion.

Some of the test houses I have spoken to state that they definitely ground
their chambers via ground spikes. This is to remove low frequency noise that
causes issues with the low frequency emc tests  that are required in
mil-std, def stan  and rtca/do-160.
One test house I spoke to stated that as a result of cost cutting an earth
spike was not fitted so earthing was taken to building ground, as a result
of this the test house has issues with low frequency noise.

The consensus of the forum is that a ground spike should not be required and
the building ground used should be enough.

This then probably raises the question of how good is the building ground?
Is there a requirement for this?
If there is noise on the building ground how can this be eliminated?

Regards
Andy



 Andrew Price
 Land & Naval Defence Electronics Division
 Prinicpal Environmental Engineer (EMC)

 Leonardo MW Ltd
 Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
 Tel  EMC LAB : +44 (0)1268 883308
 Mobile: +44 (0)7507 854888
 
andrew.p.pr...@leonardocompany.com<mailto:andrew.p.pr...@leonardocompany.com
>
 leonardocomapany.com
HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS /
SPACE

* Please consider the environment before printing this email.




Leonardo MW Ltd
Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex
SS14 3EL A company registered in England & Wales.  Company no. 02426132

This email and any attachments are confidential to the intended recipient
and may also be privileged. If you are not the intended recipient please
delete it from your system and notify the sender.
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All emc-

Re: [PSES] Chamber grounding [General Use]

[John Woodgate]

It's not my consensus! Yes, the building ground is likely to be noisy,
unless you actually connect directly back to its earth spike. Even then, the
wire you use is an inductor and may have noise induced in it. 

I am quite sure that BS 7671 and other Code standards do not recognize that
a screened room is outside their scopes. 

With best wishes DESIGN IT IN! OOO - Own Opinions Only
www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England

Sylvae in aeternum manent.

-Original Message-
From: Price, Andrew (Leonardo, UK)
[mailto:andrew.p.pr...@leonardocompany.com] 
Sent: 19 July 2017 07:16
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]

Thanks all for the replies.

It seems that there is some divided opinion.

Some of the test houses I have spoken to state that they definitely ground
their chambers via ground spikes. This is to remove low frequency noise that
causes issues with the low frequency emc tests  that are required in
mil-std, def stan  and rtca/do-160.
One test house I spoke to stated that as a result of cost cutting an earth
spike was not fitted so earthing was taken to building ground, as a result
of this the test house has issues with low frequency noise.

The consensus of the forum is that a ground spike should not be required and
the building ground used should be enough.

This then probably raises the question of how good is the building ground?
Is there a requirement for this?
If there is noise on the building ground how can this be eliminated?

Regards
Andy



 Andrew Price
 Land & Naval Defence Electronics Division
 Prinicpal Environmental Engineer (EMC)

 Leonardo MW Ltd
 Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
 Tel  EMC LAB : +44 (0)1268 883308
 Mobile: +44 (0)7507 854888
 
andrew.p.pr...@leonardocompany.com<mailto:andrew.p.pr...@leonardocompany.com
>
 leonardocomapany.com
HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS /
SPACE

* Please consider the environment before printing this email.




Leonardo MW Ltd
Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex
SS14 3EL A company registered in England & Wales.  Company no. 02426132

This email and any attachments are confidential to the intended recipient
and may also be privileged. If you are not the intended recipient please
delete it from your system and notify the sender.
You should not copy it or use it for any purpose nor disclose or distribute
its contents to any other person.


-

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David Heald: 

Re: [PSES] Chamber grounding [General Use]

[Price, Andrew (Leonardo, UK)]

Thanks all for the replies.

It seems that there is some divided opinion.

Some of the test houses I have spoken to state that they definitely ground 
their chambers via ground spikes. This is to remove low frequency noise that 
causes issues with the low frequency emc tests  that are required in mil-std, 
def stan  and rtca/do-160.
One test house I spoke to stated that as a result of cost cutting an earth 
spike was not fitted so earthing was taken to building ground, as a result of 
this the test house has issues with low frequency noise.

The consensus of the forum is that a ground spike should not be required and 
the building ground used should be enough.

This then probably raises the question of how good is the building ground? Is 
there a requirement for this?
If there is noise on the building ground how can this be eliminated?

Regards
Andy



 Andrew Price
 Land & Naval Defence Electronics Division
 Prinicpal Environmental Engineer (EMC)

 Leonardo MW Ltd
 Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
 Tel  EMC LAB : +44 (0)1268 883308
 Mobile: +44 (0)7507 854888
 
andrew.p.pr...@leonardocompany.com
 leonardocomapany.com
HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS / SPACE

* Please consider the environment before printing this email.




Leonardo MW Ltd
Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 
3EL
A company registered in England & Wales.  Company no. 02426132

This email and any attachments are confidential to the intended
recipient and may also be privileged. If you are not the intended
recipient please delete it from your system and notify the sender.
You should not copy it or use it for any purpose nor disclose or
distribute its contents to any other person.


-

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Re: [PSES] Chamber grounding [General Use]

[ce-test, qualified testing bv, Gert Gremmen]

I agree that (national) legislation should play a role here,
but EMC chambers are NOT ordinary equipments, nor
part of a standard electrical installation.
I would not rely on electrical codes to create a safe work environment,
and have my personal opinions prevail.

We operate in a gray area, where safety is concerned.


So here good (low voltage) engineering practice suggests "permanent
connection"
and due to the specifically lethal character of the "high leakage current
device"
of the device, a second backup connection is not superfluous.

Gert


From: John Woodgate [mailto:jmw1...@btinternet.com] 
Sent: Tuesday 18 July 2017 21:09
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]

I think the issue is far more about electrical safety than EMC. Of course
you are quite right about a Faraday cage not requiring an earth connection.
It's what happens if there is a high-current live mains to accessible metal
fault. The preferred technique depends on how such a fault is detected and
rendered harmless. National electrical codes have much to say about this,
and they don't all require the same solutions. That's why I advised the OP
to look at BS 7694, because that is what applies in Britain.


With best wishes DESIGN IT IN! OOO - Own Opinions Only
www.jmwa.demon.co.uk <http://www.jmwa.demon.co.uk/>  J M Woodgate and
Associates Rayleigh England

Sylvae in aeternum manent.

From: Ghery S. Pettit [mailto:n6...@comcast.net] 
Sent: 18 July 2017 19:59
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]

It's not so much that it needs filtering at the power frequency as it is
that that much line to ground capacitance is needed to provide 100 dB of
insertion loss down to 10 kHz (which is typical for chamber power filters).

Back to the original question -

I've had 3 and 10 meter chambers in different places over the years.  The
first chamber was built before I joined the company and the engineer worked
very hard to maintain a single point ground for the chamber.  I built a 10
meter chamber for the same company a number of years later and didn't worry
about a single point ground.  Both worked fine.  A Faraday Cage, once you
are talking high enough frequencies (and 10 kHz is high enough), doesn't
care if it is ungrounded, single point grounded or multi-point grounded.
The RF currents flow close enough to the surface that the shield is good.

Now, if you have a problem with 60 Hz power causing currents to flow through
the shield material you may have a different problem.  I've never had to
care about shielding effectiveness at 60 Hz, so skin effect hasn't been an
issue for me.  YMMV.

Ghery S. Pettit, NCE


From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Tuesday, July 18, 2017 11:47 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]


"But as soon as mains filters are mounted on the wall, one has to cope with
leakage currents (blind current) as large as 6 amp or more." 
6 amps!  At 230 volts, 50 Hz, Xc is 38.8 ohms.  Total C from line to earth
is 69.2 uF!  (Presumably the filter has an equal capacitance from neutral to
earth.)  Why does a chamber need so much filtering at mains frequency?

Rich


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Re: [PSES] Chamber grounding [General Use]

[John Woodgate]

I think the issue is far more about electrical safety than EMC. Of course
you are quite right about a Faraday cage not requiring an earth connection.
It's what happens if there is a high-current live mains to accessible metal
fault. The preferred technique depends on how such a fault is detected and
rendered harmless. National electrical codes have much to say about this,
and they don't all require the same solutions. That's why I advised the OP
to look at BS 7694, because that is what applies in Britain.
 
 
With best wishes DESIGN IT IN! OOO - Own Opinions Only
 <http://www.jmwa.demon.co.uk/> www.jmwa.demon.co.uk J M Woodgate and
Associates Rayleigh England
 
Sylvae in aeternum manent.
 
From: Ghery S. Pettit [mailto:n6...@comcast.net] 
Sent: 18 July 2017 19:59
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]
 
It's not so much that it needs filtering at the power frequency as it is
that that much line to ground capacitance is needed to provide 100 dB of
insertion loss down to 10 kHz (which is typical for chamber power filters).
 
Back to the original question -
 
I've had 3 and 10 meter chambers in different places over the years.  The
first chamber was built before I joined the company and the engineer worked
very hard to maintain a single point ground for the chamber.  I built a 10
meter chamber for the same company a number of years later and didn't worry
about a single point ground.  Both worked fine.  A Faraday Cage, once you
are talking high enough frequencies (and 10 kHz is high enough), doesn't
care if it is ungrounded, single point grounded or multi-point grounded.
The RF currents flow close enough to the surface that the shield is good.
 
Now, if you have a problem with 60 Hz power causing currents to flow through
the shield material you may have a different problem.  I've never had to
care about shielding effectiveness at 60 Hz, so skin effect hasn't been an
issue for me.  YMMV.
 
Ghery S. Pettit, NCE
 
 
From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Tuesday, July 18, 2017 11:47 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] Chamber grounding [General Use]
 
 
"But as soon as mains filters are mounted on the wall, one has to cope with
leakage currents (blind current) as large as 6 amp or more." 
6 amps!  At 230 volts, 50 Hz, Xc is 38.8 ohms.  Total C from line to earth
is 69.2 uF!  (Presumably the filter has an equal capacitance from neutral to
earth.)  Why does a chamber need so much filtering at mains frequency?
 
Rich
 
 
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Attachments ar

Re: [PSES] Chamber grounding [General Use]

[Ken Javor]

In the US, 120 Vac and 60 Hz.  The filter has a pass band below 1 kHz, and a
stop band of 100 dB at 10 kHz.  That requires large amounts of
line-to-ground capacity and series inductance, and obviously at least five
poles.

Ken Javor
Phone: (256) 650-5261



From: Richard Nute 
Reply-To: 
Date: Tue, 18 Jul 2017 11:47:22 -0700
To: 
Subject: Re: [PSES] Chamber grounding [General Use]

 
³But as soon as mains filters are mounted on the wall, one has to cope with
leakage currents (blind current) as large as 6 amp or more.²

6 amps!  At 230 volts, 50 Hz, Xc is 38.8 ohms.  Total C from line to earth
is 69.2 uF!  (Presumably the filter has an equal capacitance from neutral to
earth.)  Why does a chamber need so much filtering at mains frequency?
 
Rich
 
 
-


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For policy questions, send mail to:
Jim Bacher  
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Re: [PSES] Chamber grounding [General Use]

[Ghery S. Pettit]

It's not so much that it needs filtering at the power frequency as it is
that that much line to ground capacitance is needed to provide 100 dB of
insertion loss down to 10 kHz (which is typical for chamber power filters).

 

Back to the original question -

 

I've had 3 and 10 meter chambers in different places over the years.  The
first chamber was built before I joined the company and the engineer worked
very hard to maintain a single point ground for the chamber.  I built a 10
meter chamber for the same company a number of years later and didn't worry
about a single point ground.  Both worked fine.  A Faraday Cage, once you
are talking high enough frequencies (and 10 kHz is high enough), doesn't
care if it is ungrounded, single point grounded or multi-point grounded.
The RF currents flow close enough to the surface that the shield is good.

 

Now, if you have a problem with 60 Hz power causing currents to flow through
the shield material you may have a different problem.  I've never had to
care about shielding effectiveness at 60 Hz, so skin effect hasn't been an
issue for me.  YMMV.

 

Ghery S. Pettit, NCE

 

 

From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Tuesday, July 18, 2017 11:47 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]

 

 

"But as soon as mains filters are mounted on the wall, one has to cope with
leakage currents (blind current) as large as 6 amp or more." 

6 amps!  At 230 volts, 50 Hz, Xc is 38.8 ohms.  Total C from line to earth
is 69.2 uF!  (Presumably the filter has an equal capacitance from neutral to
earth.)  Why does a chamber need so much filtering at mains frequency?

 

Rich

 

 

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Re: [PSES] Chamber grounding [General Use]

[Richard Nute]

 

"But as soon as mains filters are mounted on the
wall, one has to cope with leakage currents (blind
current) as large as 6 amp or more." 

6 amps!  At 230 volts, 50 Hz, Xc is 38.8 ohms.
Total C from line to earth is 69.2 uF!
(Presumably the filter has an equal capacitance
from neutral to earth.)  Why does a chamber need
so much filtering at mains frequency?

 

Rich

 

 


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Re: [PSES] Chamber grounding [General Use]

[James Pawson (U3C)]

Hi Brian,

My understanding is that GTEMs struggle when anything involving cables is
mentioned, presumably because no one can agree on an accurate, consistent,
standardised method for routing them out of the test volume. 61000-4-20 has
a clause in it that states that EUTs with cables are under consideration or
outside the scope of the standard (I don't have it in front of me).

Al the best
James


James Pawson
Unit 3 Compliance
www.unit3compliance.co.uk



-Original Message-
From: Brian O'Connell [mailto:oconne...@tamuracorp.com] 
Sent: 18 July 2017 18:23
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]

Warning Will Robinson - Brian is not an EMC expert.

Agree with Herr Gremmen about the referencing of equipotential points - this
was critical for my employer's current chamber because it was sitting next
to a machine shop and a HALT chamber. Would suggest two or three cups of
tea, followed by some ale, while pursuing a good reading of the EN50147-x
series and ANSIC63.4 and CISPR16 and the various Bugs Bunny cartoons.

Related question - am wondering why, other than physical size of UUT,
industry prefers anechoics in lieu of GTEMs? 

Brian


From: Gert Gremmen [mailto:g.grem...@cetest.nl]
Sent: Tuesday, July 18, 2017 8:49 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]

As for the purpose of operation, EMC chambers need no grounding.
The shielding property happens by conduction of the shield material the
chamber is made from.
But as soon as mains filters are mounted on the wall, one has to cope with
leakage currents (blind current) as large as 6 amp or more. This is
definitely lethal on the touch so I recommend a grounding of 4-6mm2 copper
in addition to the ground lead in the mains connection.
I suggest leading both grounds to the building ground, as that is an
equipotential point, made for safety.
But again, an ungrounded chamber performs the same as a grounded one.
Gert Gremme
-Oorspronkelijk bericht-
Van: Price, Andrew (Leonardo, UK)
[mailto:andrew.p.pr...@leonardocompany.com]
Verzonden: dinsdag 18 juli 2017 16:55
Aan: EMC-PSTC@LISTSERV.IEEE.ORG
Onderwerp: Re: [PSES] Chamber grounding [General Use] Hi All Which is the
best to use?
Ground each EMC chamber via an earth spike or back to the transformer of the
supply to the building?
Which is best practice?
Regards
Andy

 Andrew Price
 Land & Naval Defence Electronics Division
 Prinicpal Environmental Engineer (EMC)
 Leonardo MW Ltd
 Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
 Tel  EMC LAB : +44 (0)1268 883308
 Mobile: +44 (0)7507 854888

andrew.p.pr...@leonardocompany.com<mailto:andrew.p.pr...@leonardocompany.com
>
 leonardocomapany.com
HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS /
SPACE
* Please consider the environment before printing this email.


Leonardo MW Ltd
Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex
SS14 3EL A company registered in England & Wales.  Company no. 02426132


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Re: [PSES] Chamber grounding [General Use]

[Ken Javor]

I was pondering how best to answer the OP but Gert Gremmen beat me to it
with better words than I would have used.

With regards to the last question, GTEMs are only good for the test sample
enclosure itself, not the attached cables. When using a GTEM, I have told
customers to measure cable common mode conducted emissions (CMCE) first,
control them to a level based on an algorithm relating CMCE to RE at the
required separation, and when that is complete, go into the GTEM and any
failures are then known to originate from the test sample enclosure, not the
cables. Similarly, for RS, apply BCI or 61000-4-6 to the cables at the
appropriate level first, then go into the cell and any problems found there
are due to the test sample enclosure.

Ken Javor
Phone: (256) 650-5261



> From: Brian O'Connell 
> Reply-To: Brian O'Connell 
> Date: Tue, 18 Jul 2017 17:22:35 +
> To: 
> Conversation: [PSES] Chamber grounding [General Use]
> Subject: Re: [PSES] Chamber grounding [General Use]
> 
> Warning Will Robinson - Brian is not an EMC expert.
> 
> Agree with Herr Gremmen about the referencing of equipotential points - this
> was critical for my employer's current chamber because it was sitting next to
> a machine shop and a HALT chamber. Would suggest two or three cups of tea,
> followed by some ale, while pursuing a good reading of the EN50147-x series
> and ANSIC63.4 and CISPR16 and the various Bugs Bunny cartoons.
> 
> Related question - am wondering why, other than physical size of UUT, industry
> prefers anechoics in lieu of GTEMs?
> 
> Brian
> 
> 
> From: Gert Gremmen [mailto:g.grem...@cetest.nl]
> Sent: Tuesday, July 18, 2017 8:49 AM
> To: EMC-PSTC@LISTSERV.IEEE.ORG
> Subject: Re: [PSES] Chamber grounding [General Use]
> 
> As for the purpose of operation, EMC chambers need no grounding.
> The shielding property happens by conduction of the shield material the
> chamber is made from.
> But as soon as mains filters are mounted on the wall, one has to cope with
> leakage currents
> (blind current) as large as 6 amp or more. This is definitely lethal on the
> touch so I recommend a
> grounding of 4-6mm2 copper in addition to the ground lead in the mains
> connection.
> I suggest leading both grounds to the building ground, as that is an
> equipotential point, made for safety.
> But again, an ungrounded chamber performs the same as a grounded one.
> Gert Gremme
> -Oorspronkelijk bericht-
> Van: Price, Andrew (Leonardo, UK) [mailto:andrew.p.pr...@leonardocompany.com]
> Verzonden: dinsdag 18 juli 2017 16:55
> Aan: EMC-PSTC@LISTSERV.IEEE.ORG
> Onderwerp: Re: [PSES] Chamber grounding [General Use]
> Hi All
> Which is the best to use?
> Ground each EMC chamber via an earth spike or back to the transformer of the
> supply to the building?
> Which is best practice?
> Regards
> Andy
> 
>  Andrew Price
>  Land & Naval Defence Electronics Division
>  Prinicpal Environmental Engineer (EMC)
>  Leonardo MW Ltd
>  Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
>  Tel  EMC LAB : +44 (0)1268 883308
>  Mobile: +44 (0)7507 854888
>  
> andrew.p.pr...@leonardocompany.com<mailto:andrew.p.pr...@leonardocompany.com>
>  leonardocomapany.com
> HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS / SPACE
> * Please consider the environment before printing this email.
> 
> 
> Leonardo MW Ltd
> Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14
> 3EL A company registered in England & Wales.  Company no. 02426132
> 
> 
> -
> 
> 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)
> List rules: http://www.ieee-pses.org/listrules.html
> 
> For help, send mail to the list administrators:
> Scott Douglas 
> Mike Cantwell 
> 
> For policy questions, send mail to:
> Jim Bacher:  
> David Heald: 

-

This message is from the IEEE Product Safety Engineering Society

Re: [PSES] Chamber grounding [General Use]

[Brian O'Connell]

Warning Will Robinson - Brian is not an EMC expert.

Agree with Herr Gremmen about the referencing of equipotential points - this 
was critical for my employer's current chamber because it was sitting next to a 
machine shop and a HALT chamber. Would suggest two or three cups of tea, 
followed by some ale, while pursuing a good reading of the EN50147-x series and 
ANSIC63.4 and CISPR16 and the various Bugs Bunny cartoons.

Related question - am wondering why, other than physical size of UUT, industry 
prefers anechoics in lieu of GTEMs? 

Brian


From: Gert Gremmen [mailto:g.grem...@cetest.nl] 
Sent: Tuesday, July 18, 2017 8:49 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Chamber grounding [General Use]

As for the purpose of operation, EMC chambers need no grounding.
The shielding property happens by conduction of the shield material the chamber 
is made from.
But as soon as mains filters are mounted on the wall, one has to cope with 
leakage currents
(blind current) as large as 6 amp or more. This is definitely lethal on the 
touch so I recommend a
grounding of 4-6mm2 copper in addition to the ground lead in the mains 
connection.
I suggest leading both grounds to the building ground, as that is an
equipotential point, made for safety.
But again, an ungrounded chamber performs the same as a grounded one.
Gert Gremme
-Oorspronkelijk bericht-
Van: Price, Andrew (Leonardo, UK) [mailto:andrew.p.pr...@leonardocompany.com]
Verzonden: dinsdag 18 juli 2017 16:55
Aan: EMC-PSTC@LISTSERV.IEEE.ORG
Onderwerp: Re: [PSES] Chamber grounding [General Use]
Hi All
Which is the best to use?
Ground each EMC chamber via an earth spike or back to the transformer of the 
supply to the building?
Which is best practice?
Regards
Andy

 Andrew Price
 Land & Naval Defence Electronics Division
 Prinicpal Environmental Engineer (EMC)
 Leonardo MW Ltd
 Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
 Tel  EMC LAB : +44 (0)1268 883308
 Mobile: +44 (0)7507 854888
 
andrew.p.pr...@leonardocompany.com<mailto:andrew.p.pr...@leonardocompany.com>
 leonardocomapany.com
HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS / SPACE
* Please consider the environment before printing this email.


Leonardo MW Ltd
Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 
3EL A company registered in England & Wales.  Company no. 02426132


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Re: [PSES] Chamber grounding [General Use]

[Gert Gremmen]

As for the purpose of operation, EMC chambers need no grounding.
The shielding property happens by conduction of the shield material the
chamber is made from.

But as soon as mains filters are mounted on the wall, one has to cope with
leakage currents
(blind current) as large as 6 amp or more. This is definitely lethal on the
touch so I recommend a
grounding of 4-6mm2 copper in addition to the ground lead in the mains
connection.

I suggest leading both grounds to the building ground, as that is an
equipotential point, made for safety.

But again, an ungrounded chamber performs the same as a grounded one.

Gert Gremme


-Oorspronkelijk bericht-
Van: Price, Andrew (Leonardo, UK)
[mailto:andrew.p.pr...@leonardocompany.com] 
Verzonden: dinsdag 18 juli 2017 16:55
Aan: EMC-PSTC@LISTSERV.IEEE.ORG
Onderwerp: Re: [PSES] Chamber grounding [General Use]

Hi All

Which is the best to use?
Ground each EMC chamber via an earth spike or back to the transformer of the
supply to the building?
Which is best practice?

Regards
Andy



 Andrew Price
 Land & Naval Defence Electronics Division
 Prinicpal Environmental Engineer (EMC)

 Leonardo MW Ltd
 Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
 Tel  EMC LAB : +44 (0)1268 883308
 Mobile: +44 (0)7507 854888
 
andrew.p.pr...@leonardocompany.com<mailto:andrew.p.pr...@leonardocompany.com
>
 leonardocomapany.com
HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS /
SPACE

* Please consider the environment before printing this email.




Leonardo MW Ltd
Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex
SS14 3EL A company registered in England & Wales.  Company no. 02426132

This email and any attachments are confidential to the intended recipient
and may also be privileged. If you are not the intended recipient please
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Re: [PSES] Chamber grounding [General Use]

[Price, Andrew (Leonardo, UK)]

Hi All

Which is the best to use?
Ground each EMC chamber via an earth spike or back to the transformer of the 
supply to the building?
Which is best practice?

Regards
Andy



 Andrew Price
 Land & Naval Defence Electronics Division
 Prinicpal Environmental Engineer (EMC)

 Leonardo MW Ltd
 Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
 Tel  EMC LAB : +44 (0)1268 883308
 Mobile: +44 (0)7507 854888
 
andrew.p.pr...@leonardocompany.com
 leonardocomapany.com
HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS / SPACE

* Please consider the environment before printing this email.




Leonardo MW Ltd
Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 
3EL
A company registered in England & Wales.  Company no. 02426132

This email and any attachments are confidential to the intended
recipient and may also be privileged. If you are not the intended
recipient please delete it from your system and notify the sender.
You should not copy it or use it for any purpose nor disclose or
distribute its contents to any other person.


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