You would also have to consider the frequency involved. At "very high"
frequencies you probably could not get a good RF ground no matter what
method you used to ground a hinged panel.
Bob Heller
3M EMC Laboratory, 76-1-01
St. Paul, MN 55107-1208
Tel: 651- 778-6336
Fax: 651-778-6252
===================================================================
From: John Cochran <[email protected]>
To: Doug Nix <[email protected]>
Cc: "[email protected]" <[email protected]>
Date: 12/22/2009 11:39 AM
Subject: RE: [PSES] Electrical components on hinged panels
Sent by: <[email protected]>
Thank you, Doug. Looks like we have some rewiring to do. I greatly
appreciate your finding this information for me.
Thanks,
John
From: Doug Nix [mailto:[email protected]]
Sent: Tuesday, December 22, 2009 11:12 AM
To: John Cochran
Cc: [email protected]
Subject: Re: [PSES] Electrical components on hinged panels
John,
Here is the relevant text. Bolding added for emphasis:
EN 60204-1:2006
11 Controlgear: location, mounting, and enclosures
11.1 General requirements
All controlgear shall be located and mounted so as to facilitate:
- its accessibility and maintenance;
- its protection against the external influences or conditions under
which it is intended to
operate;
- operation and maintenance of the machine and its associated
equipment.
11.2 Location and mounting
11.2.1 Accessibility and maintenance
All items of control gear shall be placed and oriented so that they
can be identified without moving them or the wiring. For items that
require checking for correct operation or that are liable to need
replacement, those actions should be possible without dismantling
other equipment or parts of the machine (except opening doors or
removing covers, barriers or obstacles). Terminals not part of
controlgear components or devices shall also conform to these
requirements.
All controlgear shall be mounted so as to facilitate its operation and
maintenance from the front. Where a special tool is necessary to
adjust, maintain, or remove a device, such a tool shall be supplied.
Where access is required for regular maintenance or adjustment, the
relevant devices shall be located between 0,4 m and 2,0 m above the
servicing level. It is recommended that terminals be at least 0,2 m
above the servicing level and be so placed that copductors and cables
can be easily connected to them.
No devices except devices for operating, indicating, measuring, and
cooling shall be mounted on doors or on normally removable access
covers of enclosures. Where control devices are connected through
plug-in arrangements, their association shall be made clear by type
(shape), marking or reference designation, singly or in combination
(see 13.4.5).
Plug-in devices that are handled during normal operation shall be
provided with non-interchangeable features where the lack of such a
facility can result in malfunctioning.
PIug/socket combinations that· are handled during normal operation
shall be located and mounted so as to provide unobstructed access.
Test points for connection of test equipment, where provided, shall
be:
- mounted so as to provide unobstructed access;
- clearly identified to correspond with the documentation (see 17.3);
- adequately insulated;
- sufficiently spaced.
Normally this is taken to mean that pushbuttons, selector switches, pilot
lights, HMIs, cooling fans, and instruments may be mounted on doors or
removable covers. PLC's and remote I/O blocks are not normally included,
although you might be able to successfully argue that installing a remote
I/O block on the door lessens the amount of wiring that must cross the
hinge, and is therefore preferable to running discrete wiring.
Also note that there is a requirement for the wiring to be highly flexible:
13.3 Wiring inside enclosures
Conductors inside enclosures shall be supported where necessary to
keep them in place. Non-metallic ducts shall be permitted only when
they are made with a flame-retardant insulating material (see the IEC
60332 series).
It is recommended that electrical equipment mounted inside enclosures
be designed and constructed in such a way as to permit modification of
the wiring from the front of the enclosure (see also 11.2.1). Where
that is not practicable and control devices are connected from the
rear of the enclosure, access doors or swingout panels shall be
provided.
Connections to devices mounted on doors or to other movable parts
shall be made using flexible conductors in accordance with 12.2 and
12.6 to allow for the frequent movement of the part. The conductors
shall be anchored to the fixed part and to the movable part
independently of the electrical connection (see also 8.2.3 and
11.2.1).
Conductors and cables that do not run in ducts shall be adequately
supported.
Terminal blocks or plug/socket combinations shall be used for control
wIFIng that extends beyond the enclosure. For plug/socket
combinations, see also 13.4.5 and 13.4.6.
Power cables and cables of measuring circuits may be directly
connected to the terminals of the devices for which the connections
were intended.
Section 12.2 deals with wiring materials, gauge and ampacity. Section 12.6
deals with the specific requirements for flexible cables. I'll leave you to
review those sections on your own.
Feel free to contact me with any questions.
Happy Holidays to all!
--
Doug Nix, A.Sc.T.
IEEE PSES Toronto Chapter
Toronto Section, Ontario, Canada
[email protected]
office: +1 (519) 650-4753
mobile +1 (519) 729-5704
fax +1 (519) 653-1318
Find me LinkedIn at http://www.linkedin.com/in/dougnix
On 22-Dec-09, at 09:27 , John Cochran wrote:
I have asked for the specific standard and clause that the inspector is
using to declare our cart is unacceptable for installing components on the
door. The product is a mobile control station for use in industrial
process control. It contains a server and UPS in the main enclosure, with
a Control Logix controller, Ethernet router and 24VDC power supply on the
door. Main incoming power is terminated in the main enclosure through a
16A breaker and protective earth ground is permanently connected to the
stainless steel enclosure. The power is then run to the UPS in the main
enclosure bottom, then out of the UPS to the door for distribution to all
the components through 5A breakers. This also includes coming back across
the door hinge to the server and display. A separate permanently attached
ground braid is run between the main enclosure and the door, to connect
protective earth to the door. Guess I have to look at the EN60204 and see
if I can find any problems with our wiring practices.
John
From: [email protected] [mailto:[email protected]] On Behalf Of John Allen
Sent: Monday, December 21, 2009 9:10 PM
To: Doug Nix
Cc: [email protected]
Subject: Re: [PSES] Electrical components on hinged panels
Pretty sure it's allowed but would have to verify. EN60204 should be the
Standard for the panel. Ask the inspector to point to a Standard and
clause.
On Dec 21, 2009, at 5:50 PM, Doug Nix <[email protected]> wrote:
John,
Is this industrial equipment?
--
Doug Nix, A.Sc.T.
IEEE PSES Toronto Chapter
Toronto Section, Ontario, Canada
[email protected]
mobile (519) 729-5704
fax (519) 653-1318
Find me LinkedIn at http://www.linkedin.com/in/dougnix
Fostering Technological Innovation and Excellence for the Benefit of
Humanity. Celebrating 125 Years of Engineering the Future.
http://www.ieee125.org
On 21-Dec-09, at 17:51 , John Cochran wrote:
Do you know if there is a CE compliance issue with attaching
electrical components to a hinged door? For ease of construction, we
often attach components to the access door of our industrial control
panel enclosures. UL has evaluated our construction methods and
certified us a UL508 Panel Shop. Criteria is that a solid earth
ground is attached to the door, and all electrical cables are
protected against damage. We are being told by a customer that
electrical components are never allowed on a door, in compliance with
CE. If UL finds it acceptable, I am not sure why it would be
unacceptable for Europe. I have seen many enclosures in Europe with
electrical components on a removable panel or door. Is the inspector
exercising personal preference, or is there a compliance standard
that backs up this decision to reject our wiring practices?
Thanks,
John Cochran
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