Re: [PSES] standard for power suply for server room.

2016-09-21 Thread Douglas Nix
All,

600 V is standard in Canada.

--
Doug Nix
d...@mac.com
http://www.dougnix.net


If you pick up a starving dog and make him prosperous, he will not bite you; 
that is the principal difference between a dog and a man. - Mark Twain 

> On 21-Sep-16, at 15:52, Richard Nute  wrote:
> 
>  
> I would seriously consider pointing out to your customer that their specified 
> supply voltage is not a common one
>  
> I suspect your customer already knows this.  The issue is determining that 
> the product is safe, given that the mains ratings exceed those in many safety 
> standards.  While standards such as 60950 state that they are applicable to 
> 600 V rms (there is a statement in the standard that unless otherwise noted, 
> all voltages are rms), as has been mentioned, the clearance, creepage, and 
> electric strength requirements go well beyond 600 V.  
>  
> Clearance and electric strength requirements are based on transient 
> overvoltages.  Transient overvoltages come from lightning strikes and 
> switching.  DC mains may not be outside the local building so may not be 
> subject to either or both of these sources of overvoltages, so the clearances 
> and electric strength requirements may not be applicable to this equipment.  
> I believe 62368 so states.
>  
> Rich
>  
>  
>  
> -
> 
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Re: [PSES] standard for power suply for server room.

2016-09-21 Thread john Allen
Rich & friends 

 

Whilst I generally agree with what you said, if the customer already knows the 
system to which he needs connections, then it is only reasonable to ask him to 
clarify what his requirements and constraints are!

 

I would also point out that other factors like altitude also affect dielectric 
strength tests  and so on so, please still ask the questions, or thereabouts.

 

John E Allen

W.London, UK

 

From: Richard Nute [mailto:ri...@ieee.org] 
Sent: 21 September 2016 20:52
To: 'john Allen'; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] standard for power suply for server room.

 

 

I would seriously consider pointing out to your customer that their specified 
supply voltage is not a common one

 

I suspect your customer already knows this.  The issue is determining that the 
product is safe, given that the mains ratings exceed those in many safety 
standards.  While standards such as 60950 state that they are applicable to 600 
V rms (there is a statement in the standard that unless otherwise noted, all 
voltages are rms), as has been mentioned, the clearance, creepage, and electric 
strength requirements go well beyond 600 V.  

 

Clearance and electric strength requirements are based on transient 
overvoltages.  Transient overvoltages come from lightning strikes and 
switching.  DC mains may not be outside the local building so may not be 
subject to either or both of these sources of overvoltages, so the clearances 
and electric strength requirements may not be applicable to this equipment.  I 
believe 62368 so states.

 

Rich

 

 

 


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Re: [PSES] standard for power suply for server room.

2016-09-21 Thread Richard Nute
 

I would seriously consider pointing out to your customer that their specified 
supply voltage is not a common one

 

I suspect your customer already knows this.  The issue is determining that the 
product is safe, given that the mains ratings exceed those in many safety 
standards.  While standards such as 60950 state that they are applicable to 600 
V rms (there is a statement in the standard that unless otherwise noted, all 
voltages are rms), as has been mentioned, the clearance, creepage, and electric 
strength requirements go well beyond 600 V.  

 

Clearance and electric strength requirements are based on transient 
overvoltages.  Transient overvoltages come from lightning strikes and 
switching.  DC mains may not be outside the local building so may not be 
subject to either or both of these sources of overvoltages, so the clearances 
and electric strength requirements may not be applicable to this equipment.  I 
believe 62368 so states.

 

Rich

 

 

 


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Re: [PSES] standard for power suply for server room.

2016-09-21 Thread Scott Aldous
Disclaimer: I don't work on data center equipment.

Article 645 from the 2014 NEC includes the 600V rating limit in the
definition for Information Technology Equipment. The 2017 NEC no longer
includes the definition for ITE in Article 645, but 2017 NFPA 75 does and
it includes the 600V limit. In general the 600V limit comes from the
traditional US delineation between low voltage and medium voltage, however
the NEC is slowly moving toward a higher delineation point, at least for
some cases. For example the 2014 NEC changed Article 490 from covering
equipment over 600V nominal to equipment over 1000V nominal. The 2014 NEC
Handbook notes that there is a coordinated effort in this regard related to
alternative energy systems. Also see 250.180 (in general Part X of Article
250), where again starting in the 2014 NEC grounding requirements for
systems over 600V was changed to 1000V. The NEC is not clear on making a
distinction between ac/rms and dc voltages where these limits are imposed,
so the limit is generally applied regardless of waveform. In any case, this
is more of an installation issue than a product certification issue, though
for US certification it should be possible to install such equipment in
compliance with the NEC. It may be helpful to have a discussion on NEC
compliance with the customer to understand how they intend the NEC to be
applied to installations with their equipment.

With regard to certification, UL 60950-1 does include the limitation of
600V for information technology equipment, however the scope (of UL
60950-1) also indicates that the standard is also applicable to external
power supply units intended to supply other equipment within the scope of
this part of IEC 60905. Arguably, this leaves room for such an external
power supply's input not to fall under the 600V limit expressed in the
earlier part of the standard as long as the ITE it supplies falls under
that limit. In any case, Note 2 under clause 1.1.1 indicates that the
standard can be applied to electronic parts of equipment even if such
equipment doesn't wholly fall within the scope. I would think you could
apply UL 60950-1, and if there are any items that are not covered by the
requirements of the standard, you could supplement with requirements from
another standard, perhaps UL 508C
<http://ulstandards.ul.com/standard/?id=508C_3>.

On Wed, Sep 21, 2016 at 8:02 AM, john Allen <john_e_al...@blueyonder.co.uk>
wrote:

> Bostjan
>
>
>
> I would seriously consider pointing out to your customer that their
> specified supply voltage is not a common one (at all) and ask them to state
> in more detail the system configuration which will provide it, and then you
> should know more clearly what you are up against and how to deal with it.
> Mention that the voltage does not appear to coincide with any
> generally-known commercial level known to be found in Europe or N.America,
> and thus ask where it will be found - suspicion might fall on some other
> country &/or an end-use customer that has some very special equipment, and
> might also point you towards some national standard(s) that could be
> national variations on known international ones.
>
>
>
> Ignorance is not a “crime” in cases like this where “something” is very
> unusual and where no-one here on this very experienced forum can provide
> any definitive, or even “educated”, guidance.
>
>
>
> John E Allen
>
> W.London, UK
>
>
>
> *From:* Boštjan Glavič [mailto:bostjan.gla...@siq.si]
> *Sent:* 21 September 2016 05:47
> *To:* EMC-PSTC@LISTSERV.IEEE.ORG
>
> *Subject:* Re: [PSES] standard for power suply for server room.
>
>
>
> Hi Ken,
>
>
>
> UL1012 has the same limitation as 60950-1.
>
>
>
> IEC 61010-1 is not OK since it is not a laboratory equipment or measuring
> equipment.
>
> IEC 62477-1 has also limitation in the scope however limits are 1000Vac
> and 1500VDC.
>
>
>
> Best regards,
>
> Bostjan
>
>
>
> *From:* IBM Ken [mailto:ibm...@gmail.com <ibm...@gmail.com>]
> *Sent:* Wednesday, September 21, 2016 6:36 AM
> *To:* Boštjan Glavič <bostjan.gla...@siq.si>
> *Cc:* EMC-PSTC@LISTSERV.IEEE.ORG
> *Subject:* Re: [PSES] standard for power suply for server room.
>
>
>
> Hi Bostjan!
>
> You might be able to use 60950 or (UL1012?) anyway; I know the scope says
> "Mains or Battery powered up to 600V", but I think the focus of that limit
> (vs the 1000V limit in the LVD for example) might be on just Mains powered
> circuits, because 600V is the delineation point between "Low Voltage" and
> "high voltage" per the National Electrical Code.
>
>
>
> On the other hand, I believe the spacing calculations go higher than 600V
> in 60950 because internal voltages can go much higher than the supp

Re: [PSES] standard for power suply for server room.

2016-09-21 Thread john Allen
Bostjan

 

I would seriously consider pointing out to your customer that their specified 
supply voltage is not a common one (at all) and ask them to state in more 
detail the system configuration which will provide it, and then you should know 
more clearly what you are up against and how to deal with it. Mention that the 
voltage does not appear to coincide with any generally-known commercial level 
known to be found in Europe or N.America, and thus ask where it will be found - 
suspicion might fall on some other country &/or an end-use customer that has 
some very special equipment, and might also point you towards some national 
standard(s) that could be national variations on known international ones.

 

Ignorance is not a “crime” in cases like this where “something” is very unusual 
and where no-one here on this very experienced forum can provide any 
definitive, or even “educated”, guidance.

 

John E Allen

W.London, UK

 

From: Boštjan Glavič [mailto:bostjan.gla...@siq.si] 
Sent: 21 September 2016 05:47
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] standard for power suply for server room.

 

Hi Ken,

 

UL1012 has the same limitation as 60950-1. 

 

IEC 61010-1 is not OK since it is not a laboratory equipment or measuring 
equipment.

IEC 62477-1 has also limitation in the scope however limits are 1000Vac and 
1500VDC.

 

Best regards,

Bostjan

 

From: IBM Ken [mailto:ibm...@gmail.com] 
Sent: Wednesday, September 21, 2016 6:36 AM
To: Boštjan Glavič <bostjan.gla...@siq.si>
Cc: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] standard for power suply for server room.

 

Hi Bostjan!

You might be able to use 60950 or (UL1012?) anyway; I know the scope says 
"Mains or Battery powered up to 600V", but I think the focus of that limit (vs 
the 1000V limit in the LVD for example) might be on just Mains powered 
circuits, because 600V is the delineation point between "Low Voltage" and "high 
voltage" per the National Electrical Code.  

 

On the other hand, I believe the spacing calculations go higher than 600V in 
60950 because internal voltages can go much higher than the supply voltage 
(boost stages in a SMPS, inverters for CCFL tubes, HV supply for corona wire in 
a laser printer, TV flyback, etc).

 

Would 61010 work?

 

-Ken A

 

On Wed, Sep 21, 2016 at 12:09 AM, Boštjan Glavič <bostjan.gla...@siq.si> wrote:

Dear experts I again need your opinion on below issue.

 

Customer was asked for development of power supply which will be used to supply 
a  server in data centre. Input to power supply is defined as 750VDC. 
Unfortunately no information is available how this DC supply voltage is 
generated and reference to PE. Most probably it will be floating.

 

Now the problem, what standard to use for such product?

 

-  Standard IEC 60950-1 which is most often used is limited to 600V 
rated voltage. Does it mean 600VRMS? Is it then allowed to approve also 
products with 600xsqrt(2)=848VDC  rated voltage according IEC 60950-1 or limit 
is also set to 600VDC? Where this limit actually comes from? If you check 
requirements for clearance and creepage distance they go quite higher than 600V.

-  Standard IEC 62477-1 could be appropriate standard however problem 
is that this standard is not worldwide harmonised and therefore no national 
certificates (US/CAN, China) are possible based on report according to this 
standard

-  What other standard would be OK for US/CAN?

 

I appreciate your feedback.

 

Best regards,

Bostjan

 

-


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Re: [PSES] standard for power suply for server room.

2016-09-21 Thread Boštjan Glavič
Hi Zhang,

I do not know what technology they use for generating 750VDC. It could be some 
new technology.

They do not need to cover ITU or ETSI standards.

Best regards,
Bostjan

From: Zhangguoqing (A) [mailto:zhangguoq...@huawei.com]
Sent: Wednesday, September 21, 2016 11:24 AM
To: Boštjan Glavič ; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: standard for power suply for server room.

Hi Bostjan,

Why your Customer ask for 750Vdc input power supply? Normally for the DC input 
data centre equipments , the input is 400Vdc. Please find the standard ITU 
L.1200 and ITU L.1201, or ETSI 300 132-3-1, or  ATIS-0600315.01.2015.

Best Regards,
ZHANG Guoqing
Huawei Technologies Duesseldorf GmbH

From: Boštjan Glavič [mailto:bostjan.gla...@siq.si]
Sent: 2016年9月21日 6:10
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] standard for power suply for server room.

Dear experts I again need your opinion on below issue.

Customer was asked for development of power supply which will be used to supply 
a  server in data centre. Input to power supply is defined as 750VDC. 
Unfortunately no information is available how this DC supply voltage is 
generated and reference to PE. Most probably it will be floating.

Now the problem, what standard to use for such product?


-  Standard IEC 60950-1 which is most often used is limited to 600V 
rated voltage. Does it mean 600VRMS? Is it then allowed to approve also 
products with 600xsqrt(2)=848VDC  rated voltage according IEC 60950-1 or limit 
is also set to 600VDC? Where this limit actually comes from? If you check 
requirements for clearance and creepage distance they go quite higher than 600V.

-  Standard IEC 62477-1 could be appropriate standard however problem 
is that this standard is not worldwide harmonised and therefore no national 
certificates (US/CAN, China) are possible based on report according to this 
standard

-  What other standard would be OK for US/CAN?

I appreciate your feedback.

Best regards,
Bostjan

-


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discussion list. To post a message to the list, send your e-mail to 
>

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Re: [PSES] standard for power suply for server room.

2016-09-21 Thread Zhangguoqing (A)
Hi Bostjan,

Why your Customer ask for 750Vdc input power supply? Normally for the DC input 
data centre equipments , the input is 400Vdc. Please find the standard ITU 
L.1200 and ITU L.1201, or ETSI 300 132-3-1, or  ATIS-0600315.01.2015.
Best Regards,
ZHANG Guoqing
Huawei Technologies Duesseldorf GmbH

From: Boštjan Glavič [mailto:bostjan.gla...@siq.si]
Sent: 2016年9月21日 6:10
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] standard for power suply for server room.

Dear experts I again need your opinion on below issue.

Customer was asked for development of power supply which will be used to supply 
a  server in data centre. Input to power supply is defined as 750VDC. 
Unfortunately no information is available how this DC supply voltage is 
generated and reference to PE. Most probably it will be floating.

Now the problem, what standard to use for such product?


-  Standard IEC 60950-1 which is most often used is limited to 600V 
rated voltage. Does it mean 600VRMS? Is it then allowed to approve also 
products with 600xsqrt(2)=848VDC  rated voltage according IEC 60950-1 or limit 
is also set to 600VDC? Where this limit actually comes from? If you check 
requirements for clearance and creepage distance they go quite higher than 600V.

-  Standard IEC 62477-1 could be appropriate standard however problem 
is that this standard is not worldwide harmonised and therefore no national 
certificates (US/CAN, China) are possible based on report according to this 
standard

-  What other standard would be OK for US/CAN?

I appreciate your feedback.

Best regards,
Bostjan

-


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discussion list. To post a message to the list, send your e-mail to 
>

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Re: [PSES] standard for power suply for server room.

2016-09-21 Thread ce-test, qualified testing bv - Gert Gremmen
If this is for European approval, one may simply use EN 60950 and make up a 
Technical construction
file listing the essential differences. A decent (now mandatory anyway) risk 
analysis would cover these differences, showing up as in individual risks. You 
may then choose to extrapolate 6950 values, or seek another standard covering 
high voltage aspects to cover for these risks. 
I think that this would be acceptable to any international body, as long as the 
risks remain well covered.

Regards,

Ing. Gert Gremmen
Approvals manager



+ ce marking of electrical/electronic equipment
+ Independent Consultancy Services
+ Compliance Testing and Design for CE marking
 according to EC-directives:
    - Electro Magnetic Compatibility 2004/108/EC
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From: Boštjan Glavič [mailto:bostjan.gla...@siq.si] 
Sent: Wednesday 21 September 2016 06:10
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] standard for power suply for server room.

Dear experts I again need your opinion on below issue.

Customer was asked for development of power supply which will be used to supply 
a  server in data centre. Input to power supply is defined as 750VDC. 
Unfortunately no information is available how this DC supply voltage is 
generated and reference to PE. Most probably it will be floating.

Now the problem, what standard to use for such product?

- Standard IEC 60950-1 which is most often used is limited to 600V rated 
voltage. Does it mean 600VRMS? Is it then allowed to approve also products with 
600xsqrt(2)=848VDC  rated voltage according IEC 60950-1 or limit is also set to 
600VDC? Where this limit actually comes from? If you check requirements for 
clearance and creepage distance they go quite higher than 600V.
- Standard IEC 62477-1 could be appropriate standard however problem is that 
this standard is not worldwide harmonised and therefore no national 
certificates (US/CAN, China) are possible based on report according to this 
standard
- What other standard would be OK for US/CAN?

I appreciate your feedback.

Best regards,
Bostjan

-

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 

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Re: [PSES] standard for power suply for server room.

2016-09-20 Thread Boštjan Glavič
Hi Ken,

UL1012 has the same limitation as 60950-1.

IEC 61010-1 is not OK since it is not a laboratory equipment or measuring 
equipment.
IEC 62477-1 has also limitation in the scope however limits are 1000Vac and 
1500VDC.

Best regards,
Bostjan

From: IBM Ken [mailto:ibm...@gmail.com]
Sent: Wednesday, September 21, 2016 6:36 AM
To: Boštjan Glavič <bostjan.gla...@siq.si>
Cc: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] standard for power suply for server room.

Hi Bostjan!
You might be able to use 60950 or (UL1012?) anyway; I know the scope says 
"Mains or Battery powered up to 600V", but I think the focus of that limit (vs 
the 1000V limit in the LVD for example) might be on just Mains powered 
circuits, because 600V is the delineation point between "Low Voltage" and "high 
voltage" per the National Electrical Code.

On the other hand, I believe the spacing calculations go higher than 600V in 
60950 because internal voltages can go much higher than the supply voltage 
(boost stages in a SMPS, inverters for CCFL tubes, HV supply for corona wire in 
a laser printer, TV flyback, etc).

Would 61010 work?

-Ken A

On Wed, Sep 21, 2016 at 12:09 AM, Boštjan Glavič 
<bostjan.gla...@siq.si<mailto:bostjan.gla...@siq.si>> wrote:
Dear experts I again need your opinion on below issue.

Customer was asked for development of power supply which will be used to supply 
a  server in data centre. Input to power supply is defined as 750VDC. 
Unfortunately no information is available how this DC supply voltage is 
generated and reference to PE. Most probably it will be floating.

Now the problem, what standard to use for such product?


-  Standard IEC 60950-1 which is most often used is limited to 600V 
rated voltage. Does it mean 600VRMS? Is it then allowed to approve also 
products with 600xsqrt(2)=848VDC  rated voltage according IEC 60950-1 or limit 
is also set to 600VDC? Where this limit actually comes from? If you check 
requirements for clearance and creepage distance they go quite higher than 600V.

-  Standard IEC 62477-1 could be appropriate standard however problem 
is that this standard is not worldwide harmonised and therefore no national 
certificates (US/CAN, China) are possible based on report according to this 
standard

-  What other standard would be OK for US/CAN?

I appreciate your feedback.

Best regards,
Bostjan

-


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Re: [PSES] standard for power suply for server room.

2016-09-20 Thread IBM Ken
Hi Bostjan!
You might be able to use 60950 or (UL1012?) anyway; I know the scope says
"Mains or Battery powered up to 600V", but I think the focus of that limit
(vs the 1000V limit in the LVD for example) might be on just Mains powered
circuits, because 600V is the delineation point between "Low Voltage" and
"high voltage" per the National Electrical Code.

On the other hand, I believe the spacing calculations go higher than 600V
in 60950 because internal voltages can go much higher than the supply
voltage (boost stages in a SMPS, inverters for CCFL tubes, HV supply for
corona wire in a laser printer, TV flyback, etc).

Would 61010 work?

-Ken A

On Wed, Sep 21, 2016 at 12:09 AM, Boštjan Glavič 
wrote:

> Dear experts I again need your opinion on below issue.
>
>
>
> Customer was asked for development of power supply which will be used to
> supply a  server in data centre. Input to power supply is defined as
> 750VDC. Unfortunately no information is available how this DC supply
> voltage is generated and reference to PE. Most probably it will be floating.
>
>
>
> Now the problem, what standard to use for such product?
>
>
>
> -  Standard IEC 60950-1 which is most often used is limited to
> 600V rated voltage. Does it mean 600VRMS? Is it then allowed to approve
> also products with 600xsqrt(2)=848VDC  rated voltage according IEC 60950-1
> or limit is also set to 600VDC? Where this limit actually comes from? If
> you check requirements for clearance and creepage distance they go quite
> higher than 600V.
>
> -  Standard IEC 62477-1 could be appropriate standard however
> problem is that this standard is not worldwide harmonised and therefore no
> national certificates (US/CAN, China) are possible based on report
> according to this standard
>
> -  What other standard would be OK for US/CAN?
>
>
>
> I appreciate your feedback.
>
>
>
> Best regards,
>
> Bostjan
>
>
> -
> 
>
> 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 sdoug...@ieee.org
> Mike Cantwell mcantw...@ieee.org
>
> For policy questions, send mail to:
> Jim Bacher j.bac...@ieee.org
> David Heald dhe...@gmail.com
>

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For policy questions, send mail to:
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Re: [PSES] standard for power suply for server room.

2016-09-20 Thread Boštjan Glavič
Hi Doug,

Thank you for your tip. I was already thinking of it, however I believe this is 
allowed only if middle point of supply has reference to earth.

Best regards,
Bostjan



From: Doug Powell [mailto:doug...@gmail.com]
Sent: Wednesday, September 21, 2016 6:17 AM
To: Boštjan Glavič <bostjan.gla...@siq.si>; EMC-PSTC 
<EMC-PSTC@LISTSERV.IEEE.ORG>
Subject: Re: [PSES] standard for power suply for server room.

Can it be that the output is indeed floating and nominally +/- 375V?  If you 
use this, some sort of fault detection would be required to shut down if either 
end point becomes grounded. Sometimes this get tricky if the fault detection 
can be shown to fail in an unsafe way.  If achieved, you can use 600V wire on 
each output line..

All the best, Doug


From:bostjan.gla...@siq.si
Sent:September 20, 2016 10:10 PM
To:EMC-PSTC@LISTSERV.IEEE.ORG
Reply-to:bostjan.gla...@siq.si
Subject:[PSES] standard for power suply for server room.


Dear experts I again need your opinion on below issue.

Customer was asked for development of power supply which will be used to supply 
a  server in data centre. Input to power supply is defined as 750VDC. 
Unfortunately no information is available how this DC supply voltage is 
generated and reference to PE. Most probably it will be floating.

Now the problem, what standard to use for such product?


-  Standard IEC 60950-1 which is most often used is limited to 600V 
rated voltage. Does it mean 600VRMS? Is it then allowed to approve also 
products with 600xsqrt(2)=848VDC  rated voltage according IEC 60950-1 or limit 
is also set to 600VDC? Where this limit actually comes from? If you check 
requirements for clearance and creepage distance they go quite higher than 600V.

-  Standard IEC 62477-1 could be appropriate standard however problem 
is that this standard is not worldwide harmonised and therefore no national 
certificates (US/CAN, China) are possible based on report according to this 
standard

-  What other standard would be OK for US/CAN?

I appreciate your feedback.

Best regards,
Bostjan

-


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<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)<http://www.ieee-pses.org/list.html>
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
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For policy questions, send mail to:
Jim Bacher <j.bac...@ieee.org<mailto:j.bac...@ieee.org>>
David Heald <dhe...@gmail.com<mailto:dhe...@gmail.com>>

-

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:
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Attachments are not permitted but the IEEE PSES Online Communities site at 
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Re: [PSES] standard for power suply for server room.

2016-09-20 Thread Doug Powell
 Can it be that the output is indeed floating and nominally +/- 375V?  If you use this, some sort of fault detection would be required to shut down if either end point becomes grounded. Sometimes this get tricky if the fault detection can be shown to fail in an unsafe way.  If achieved, you can use 600V wire on each output line.. All the best, Doug  From:bostjan.gla...@siq.siSent:September 20, 2016 10:10 PMTo:EMC-PSTC@LISTSERV.IEEE.ORGReply-to:bostjan.gla...@siq.siSubject:[PSES] standard for power suply for server room.  







Dear experts I again need your opinion on below issue.
 
Customer was asked for development of power supply which will be used to supply a  server in data centre. Input to power supply is defined as 750VDC. Unfortunately no information is available how this DC supply voltage
 is generated and reference to PE. Most probably it will be floating.
 
Now the problem, what standard to use for such product?
 
- 
Standard IEC 60950-1 which is most often used is limited to 600V rated voltage. Does it mean 600VRMS? Is it then allowed to approve also products with 600xsqrt(2)=848VDC  rated voltage according IEC 60950-1
 or limit is also set to 600VDC? Where this limit actually comes from? If you check requirements for clearance and creepage distance they go quite higher than 600V.
- 
Standard IEC 62477-1 could be appropriate standard however problem is that this standard is not worldwide harmonised and therefore no national certificates (US/CAN, China) are possible based on report according
 to this standard
- 
What other standard would be OK for US/CAN?
 
I appreciate your feedback.
 
Best regards,
Bostjan
 



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All emc-pstc postings are archived and searchable on the web at:
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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

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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 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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