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:

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

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

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

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

Re: [PSES] Measurement Accuracy

in general, the test standards prescribe the accuracy / type of equipments and method to be used for testing. This means that measurement uncertainty has been specified indirectly. In such cases, where we are following these guidelines, the pass/fail decision can be taken based on the limits

[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

Re: [PSES] Measurement Accuracy

Measurement uncertainty depends on instruments used, method used etc. Each lab has to do calculation of measurement uncertainty for particular method. Measurement uncertainty becomes critical when results are close to the limit. High uncertainty means you have more chance to be in »a grey area«

Re: [PSES] Measurement Accuracy

ISO, International Standardization Organization, Guide to the Expression of Uncertainty in Measurement, GUM ISO, General Requirements for the Competence of testing and calibration laboratories, ISO 17025 http://www.bipm.org/en/publications/guides/gum.html Brian From: Richard Nute

Re: [PSES] Measurement Accuracy

I was wondering if anyone was aware of any guidance documents that provided acceptable levels of uncertainty when conducting various tests. I didn’t know what “uncertainty” is, so I did a Google search and found this reference:

Re: [PSES] Connection to ac mains with split end line cord

I forgot to copy the list on my response to Bostjan, but essentially my assumption was that Article 645 provides a significant exceptions to other parts of the NEC such as: prohibition on running cables through holes in floors (see 400.8), and prohibition of running non-plenum rated cables in a

Re: [PSES] Measurement Accuracy

Hi Kevin! You didn't specify the measurement method, but if you use thermocouples, does your lab use use OD5012 (used to be called OP-108 and 109)? It is also from the IECEE but gives guidance on how to prepare and use thermocouples. You asked for guidance on acceptable tolerances, which this

Re: [PSES] Connection to ac mains with split end line cord

Hi Brian, We are talking about the product with rated current > 200A and special industrial plug and special location. Why such restrictions? In EU it is recommended to have permanent connection to mains. Best regards, Bostjan On 20. sep. 2016, at 17.47, Kunde, Brian

Re: [PSES] Measurement Accuracy

Mr. Robinson, Nothing said necessarily represents the opinions or policies of my employer(s). Agree with Doug Powell's comments. Methinks this is a bit more of an internal policy for the NCB/NRTL than what has been specified by regulation or standards. The conformity assessment bodies where

Re: [PSES] Connection to ac mains with split end line cord

>From this side of the Herring Pond, it looks as though a law that requires a >plug is sensible for consumer electronics and household appliances (which is >the law in Europe), but has been extended, through excess of zeal no doubt, to >other sorts of product that can be expected to be

Re: [PSES] Measurement Accuracy

Kevin, Most certifying agencies will provide information on their expectations for measurement uncertainty. The EMC people of this world can go on for ages about the topic, you will almost always see a workshop on this at the annual EMC symposium. For safety testing this usually does not come

Re: [PSES] Connection to ac mains with split end line cord

This is a question that goes back to the beginning of time; or at least the 35 years I’ve been on the job. And I’ve never heard a good reason for either side of the argument. You don’t want unqualified people trying to wire a Plug onto a power cord and you don’t want to ship a plug that will

[PSES] Measurement Accuracy

I was wondering if anyone was aware of any guidance documents that provided acceptable levels of uncertainty when conducting various tests. The specific measurement that I am interested in this case is temperature measurements, but I would be interested in seeing other guidance for other