Re: [PSES] [EXTERNAL] [PSES] Magnets as reliable fasteners

[Don Gies]

Hi Gary,

>From your post, I zoomed in on the words "electrical panel", thinking you had 
>a product or a sub-component that is more circuit-breaker panel than A/V/ICT.

If so, I would have doubts that the North American standards would allow 
magnetic securement, but obviously compliance is checked by consulting the 
standard and the certifying engineer.

Don Gies




Internal
From: Ted Eckert <07cf6ebeab9d-dmarc-requ...@listserv.ieee.org>
Sent: Wednesday, February 9, 2022 9:33 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] [EXTERNAL] [PSES] Magnets as reliable fasteners


[External email: Use caution with links and attachments]




Hi Gary,

I have a consideration a bit different from what Doug and Mark have discussed. 
My concern is that magnets inside of an electrical panel could attract foreign 
objects. Loose screws, bolts or other hardware could be attracted to the 
magnets resulting in reduced clearances, or in the worst case, a short circuit. 
They could create a challenge for maintenance on the panels as extra care would 
be needed. I can even foresee service personnel shutting off the panel for 
maintenance and using the magnets as an impromptu tool holder. If they forget 
that a tool is held in place, there could be an electrical incident when the 
panel is reenergized.

Ted Eckert
The opinions expressed are my own and do not necessarily reflect those of my 
employer.

From: Gary Tornquist <05big...@gmail.com>
Sent: Tuesday, February 8, 2022 6:52 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [EXTERNAL] [PSES] Magnets as reliable fasteners

Hello experts,
Can magnets be used to fasten line voltage assemblies to the inside of an 
electrical panel?
To restate my concerns, if strong enough could they be considered to reliably 
maintain creepage and clearance distances, as well as not overstressing wires 
terminating at the assembly?
And how strong is strong enough?  Test T2 calls for pushing on parts in the 
most unfavorable direction with 10 newtons of force for 5 seconds - is this an 
appropriate test?

The application is in stationary equipment that does not include motors, so 
vibration should not be a concern.

I welcome advice - this is the first time I've seen such proposed construction 
and I don't know a standard such as 62368 to mention it.

Cheers,
Gary Tornquist
Product Safety Consultants
Opinions expressed are my own, not of my employer or client
-


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Re: [PSES] [EXTERNAL] [PSES] Magnets as reliable fasteners

[Ted Eckert]

Hi Gary,

I have a consideration a bit different from what Doug and Mark have discussed. 
My concern is that magnets inside of an electrical panel could attract foreign 
objects. Loose screws, bolts or other hardware could be attracted to the 
magnets resulting in reduced clearances, or in the worst case, a short circuit. 
They could create a challenge for maintenance on the panels as extra care would 
be needed. I can even foresee service personnel shutting off the panel for 
maintenance and using the magnets as an impromptu tool holder. If they forget 
that a tool is held in place, there could be an electrical incident when the 
panel is reenergized.

Ted Eckert
The opinions expressed are my own and do not necessarily reflect those of my 
employer.

From: Gary Tornquist <05big...@gmail.com>
Sent: Tuesday, February 8, 2022 6:52 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [EXTERNAL] [PSES] Magnets as reliable fasteners

Hello experts,
Can magnets be used to fasten line voltage assemblies to the inside of an 
electrical panel?
To restate my concerns, if strong enough could they be considered to reliably 
maintain creepage and clearance distances, as well as not overstressing wires 
terminating at the assembly?
And how strong is strong enough?  Test T2 calls for pushing on parts in the 
most unfavorable direction with 10 newtons of force for 5 seconds - is this an 
appropriate test?

The application is in stationary equipment that does not include motors, so 
vibration should not be a concern.

I welcome advice - this is the first time I've seen such proposed construction 
and I don't know a standard such as 62368 to mention it.

Cheers,
Gary Tornquist
Product Safety Consultants
Opinions expressed are my own, not of my employer or client
-


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Re: [PSES] Magnets as reliable fasteners

[Douglas E Powell]

Gary,

That's quite an idea, and I'm generally not one to squelch innovation.
However, most of the safety standards I work with require that
accessibility is only through use of a tool. The definition of a tool is
sometimes questioned, but typically this includes keys, screwdrivers,
pliers, coins, etc. If the assembly or cover is it is hand removable, then
this would not be considered tool only access.

One cautionary note, I've worked with at least one safety standard that
requires hazard alert labeling for static fields with magnetic flux density
high enough to affect wearable, or implanted medical devices. I actually
discovered a violation for a magnetically mounted ventilation filter that
exceeded the limits of a static field. In that instance, the limits at 0.0
Hz for Head and Torso 200 mT (2000 G), limbs 2 T (20,000 G).

If you are so inclined, you might present this to the IEC committee as a
question or suggestion.

-Doug


Douglas E Powell
Laporte, Colorado USA
doug...@gmail.com
LinkedIn 



On Tue, Feb 8, 2022 at 7:51 PM Gary Tornquist <05big...@gmail.com> wrote:

> Hello experts,
>
> Can magnets be used to fasten line voltage assemblies to the inside of an
> electrical panel?
>
> To restate my concerns, if strong enough could they be considered to
> reliably maintain creepage and clearance distances, as well as not
> overstressing wires terminating at the assembly?
>
> And how strong is strong enough?  Test T2 calls for pushing on parts in
> the most unfavorable direction with 10 newtons of force for 5 seconds – is
> this an appropriate test?
>
>
>
> The application is in stationary equipment that does not include motors,
> so vibration should not be a concern.
>
>
>
> I welcome advice – this is the first time I’ve seen such proposed
> construction and I don’t know a standard such as 62368 to mention it.
>
>
>
> Cheers,
> Gary Tornquist
> Product Safety Consultants
> Opinions expressed are my own, not of my employer or client
> -
> 
>
> 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/
> 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 
>


-- 

-Doug

Douglas E Powell
Laporte, Colorado USA
doug...@gmail.com
http://www.linkedin.com/in/dougp01

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David Heald: 

Re: [PSES] Magnets as reliable fasteners

[Stultz, Mark]

Hi Gary,
I would be very cautious here.  Magnetic attraction can degrade over time due 
to a variety of factors (thermal cycling, plating migration, corrosion, 
magnetic field cycling, among others).  While the appliance is stationary, what 
about damage due to shock or vibration during shipping?
I think in general, 63268-1 addresses this in clause 4.1.5:

4.1.5 Constructions and components not specifically covered

Where the equipment involves technologies, components and materials or methods 
of construction not specifically covered in this standard, the equipment shall 
provide safeguards not less than that generally afforded by this standard and 
the principles of safety contained herein.

The need for additional detailed requirements to cope with a new situation 
should be brought promptly to the attention of the appropriate committee.
This seems novel enough to me that it would need to be brought before the 
committee.

Best regards,

Mark Stultz


From: Gary Tornquist <05big...@gmail.com>
Sent: Tuesday, 8 February, 2022 9:52 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Magnets as reliable fasteners

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Hello experts,
Can magnets be used to fasten line voltage assemblies to the inside of an 
electrical panel?
To restate my concerns, if strong enough could they be considered to reliably 
maintain creepage and clearance distances, as well as not overstressing wires 
terminating at the assembly?
And how strong is strong enough?  Test T2 calls for pushing on parts in the 
most unfavorable direction with 10 newtons of force for 5 seconds - is this an 
appropriate test?

The application is in stationary equipment that does not include motors, so 
vibration should not be a concern.

I welcome advice - this is the first time I've seen such proposed construction 
and I don't know a standard such as 62368 to mention it.

Cheers,
Gary Tornquist
Product Safety Consultants
Opinions expressed are my own, not of my employer or client
-


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 
mailto: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/
Instructions: http://www.ieee-pses.org/list.html (including how to 
unsubscribe)
List rules: 
http://www.ieee-pses.org/listrules.html