Questions tagged [iec]
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42 questions
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Clearance calculation according to IEC 61010-1 section K.3.2
I'm designing a circuit which has to meet the standard IEC 61010-1. It has a transient voltage limitation at the input, so I can calculate my clearances according to section K.3.2.
The surge ...
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2
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469
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Why is transient voltage not taken into account when calculating creepage?
I am working through the creepage and clearance in IEC 61010-1, and I find that transient voltage (1.2 x 50 µs) is taken into account for clearance, but in creepage, only the working voltage is taken ...
- 511
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311
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Does testing the open neutral single fault condition in IEC 60601 turn the electrical equipment being tested off?
My question is about the open supply conductor fault test in the electrical safety testing of medical equipment under IEC 60601.
Given the equipment is otherwise on for the test up until this fault is ...
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Shielded Cable for IEC 61000-4-6
BSEE here but I’ve been writing firmware for twenty years and my electrical knowledge is rusty. We have a USB device we want to test to 61000-4-6. My boss is saying that because we don’t have the same ...
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Hipot Test Leakage Current - Canada IEC 62368-1
How do you get the leakage current parameter for hi-pot test? There is only tables for voltages in IEC 62368-1.
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IEC 62052-11 Heating test, what does it mean 25 K?
In IEC 62052-11, Heating test, describe as below,
7.2 Heating Under rated operating conditions, electrical circuits and insulation shall not reach a temperature which might adversely affect
the ...
- 141
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0
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151
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Dealing with IEC and NEC wiring color code in the same equipment
I am dealing with IEC and NEC standards for wiring color codes.
For the first time, I have to integrate european (and UL certified) COTS products - power supplies - into a system for the US market. ...
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2
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212
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Intrinsic safety (IEC60079-11) - assessing spark ignition of RLC circuit, but the L is placed before the zener barrier
My IS circuit contains an inductance, capacitance, and resistance. Shown below is the simplified schematic, with uncountable and countable fault applied, resulting in the most onerous condition:
The ...
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63
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Standard defining whether to strip multi-core cables inside the cable duct or close to IO Card
During the factory acceptance test (FAT) of a remote IO panel (24V, atex zone 1,) the client did not accept that the multi-core cables were stripped inside the panel wire duct. He said that they ...
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102
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Intrinsic safety connection protection between two intrinsic safety devices inside a hazardous zone
I am designing an RF module in in a hazardous zone (in the picture it is shown with DCDC and MCU etc.) My module gets power supply from AC/DC.
I read about intrinsic safety barriers from the IEC 60079-...
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Electrical Standards for Exposed DC Connections
We are trying to make a slide lock connection between two parts and thus need to have some sort of connector between them.
I am wondering if anyone is aware of a IEC standard relevant for connecting a ...
- 438
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124
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Why there are no IEC C8 to NEMA 1-15R cables?
Conntek has an IEC C8 to 1-15R adapter. C8 to CEE7/16 cables are dime a dozen on Aliexpress. Yet there are no C8 to 1-15R cables as far as I can tell. Is there an electronics/standard reason ...
- 388
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47
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Does the use of an IEC line connector on equipment require a UL cert?
My client wants to use a 12V SLA with a built-in line-powered charger in his gear. If I add an IEC AC mains line connector does this turkey now have to go through cert?
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Can an unpolarised (C7) plug be used safely in place of a polarised (C7P) plug?
I bought this AC adapter from the US to replace a broken Australian one. Unfortunately, the power brick is keyed for use with the polarised C7P plug. Unpolarised C7 appears to be the standard in ...
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2
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300
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Determination of temperature rise - Deviation of ± 5 K
I was referring IEC 61439-1 standard for the deriving the temperature rise of an assembly through comparison. We can derive the current rating of an assembly (low voltage switchboard) at any point (...
- 327
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124
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What is meant by the statement "variation at all measured points (including the ambient air temperature) does not exceed 1K/h"?
I am trying to understand a temperature rise test that is being conducted over a switchboard. The test conforms to IEC 61439-1. The clause 10.10.2.3.1 (Method of test - General) regarding the ...
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1
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215
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Why is the temperature sometimes expressed as a difference between two values and not an absolute value?
I was going through an IEC standard - 61439-1, table 6.
For aluminum, the standard specifies the value as 55K which is a temperature rise.
IEC 60085 specifies the class B insulator absolute value as ...
1
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0
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86
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IEC 61000-3-3 flicker for switches and relays
IEC 61000-3-3 shall be used for testing all 230V 50Hz AC devices with up to 16A current rating.
What about switches, relays, power plugs-basically devices that act as gateways between mains and actual ...
- 497
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1k
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What are the differences between UL1581 and UL2556 for VW-1 (Vertical Flame Test)?
In IEC62368-1, it's stated:
Wire complying with UL 2556 VW-1 is considered to comply with these
requirements.
I've asked a manufacturer if he could meet these requirements and he answered that he ...
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485
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Voltage protection level Up of SPD (surge protection device)
I was going through the datasheet of the below SPD.
https://www.phoenixcontact.com/en-pc/products/type2-surge-arrester-val-sec-t2-3c-350-fm-2905339
It says, Voltage protection level Up ≤ 1.5 kV
It ...
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0
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394
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IEC 60664-1. Rated impulse withstand voltage
In IEC 60664-1:2020 table F.1 (Rated impulse withstand voltage for equipment energized directly from the mains supply)
For 1250V, the calculated Rated Impulse with stand Voltage value is equal to ...
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3
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Why are switchgears rated in specific capacities such as 63A, 100A, 125A and so on?
I am working in a consultant industry, wherein we get the switchgears from different OEMs. I wonder why the switchgears (including fuses and fuse-gears) and control gear assemblies are rated in the ...
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4
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457
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Can I convert a stereo receiver's hard-wired two-prong power cord to an IEC C7?
Repairs to my stereo receiver require considerable disassembly.
One step requires me to unsolder the two mains leads from posts on the main circuit board.
The polarized, two-prong plug, AC cord enters ...
0
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0
answers
93
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Why are some devices labelled Class II instead of Class III despite using ELV?
For example, my table lamp has an IEC 61140 Class II marking despite it being externally supplied with 24V.
- 121
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1
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345
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Double insulation for battery operated device
I work for a lab device manufacturing firm. During the testing of our electronic pipette according to IEC 61010-1,the safety test lab asked why it did not have the symbol indicating double insulation.
...
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1k
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Is there any kind of “motor current/load limit curve”, like the one for wires?
When we try to select a motor protective circuit breaker (for an IEC induction motor), we can compare its tripping curve to the motor’s time-current curve during starting and steady-state. To avoid ...
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167
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AC/AC power supply for PCB
I am trying to source the right setup for powering this PCB:
I have found an 18 V AC/AC power supply but it has a barrel connector:
I am struggling to work out how to connect the barrel connector to ...
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How do we calculate the sub-transient current (initial symmetrical short-circuit current)?
For the ease of understanding, I have divided my questions into two sub-parts:
Per IEC 60909, the initial symmetrical short circuit current is calculated by: \$I_k"=\frac{cU_n}{\sqrt(3)Z_k}\$. ...
- 327
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2
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10k
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How to hook up a transformer to 120V AC?
I'm building a DC power supply and am stepping down my voltage from 120V (from the outlet) to 24V through a transformer. I will be soldering the 3 wires that plug into a North American electrical ...
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0
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348
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24V DC Industrial equipment - which IEC standards to comply with
I'm trying to design a commercial industrial product/PCB for the first time.
In order to do it "right", I would like to be aware about the most common IEC / IPC standards to comply with. ...
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92
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Is there any standard or norm for this situation?
Considering a metallic enclosure(which has PSU and electronics in it) with an IEC mains socket, an example shown below:
And it uses an IEC power socket such as:
For this kind of enclosure is there ...
- 2,714
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Must the device I am developing conform with IEC 61010-1:2010 standard?
I am developing a device that contains 5 inputs (piezo buttons) and 5 outputs (2x pump - induction motor, fan - induction motor with basic speed control using dimmer circuit, 2x source for LED ...
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179
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IEC 60664-1 clearance between phase and earth
With IEC 60664-1 you require clearance between phase and earth.
But if you have a resistor voltage divider between phase and earth do you need the same clearance between the pads of the resistors?
Or ...
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IEC 61010 table for creepage distances
Good day
I am making a pcb layout that is required to comply with the IEC 61010-1. In the standard, there is a table for clearances and creepages, which depends on working voltage, pollution degree ...
- 493
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1
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How to calculate power loss & voltage drop in three-phase power cables
What is the correct formula/method to calculate cable power losses in a three-phase system? I'm unable to find any IEC standard outlining the same.
If you consider 3C/4C cables, the manufacturer ...
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What are the IEC standards/certifications to look for in a DSO while making measurements pertaining analog parameters like CMRR, SNR, THD etc
I am in the process of measuring CMRR for our mixed signal system that deals with bio-signal acquisition. I am using DSOX2014A keysight entry-level oscilloscope to make measurement to derive CMRR, SNR ...
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212
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Why are computer displays Class I devices but TVs Class II?
I was wondering why all computer displays I know are Class I devices, or at least come with a Schuko plug, while all TVs I know are double insulated Class II devices?
I understand it might have ...
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2
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3k
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Do I need to insulate down conductors in a lightning protection system?
When we install seperate down conductors in an external lightning protection system, do we need to fully insulate it or need to insulate in touchable areas? Is there any requirements in IEC 62305 ...
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1
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368
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When does an electrical product get an RU (Underwriters Laboratories) certified mark?
If you take an example of contactor, it can be used in residential, industrial, electric vehicle applications etc.
Let's say the contactor has passed the UL standards corresponding to the industrial ...
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1
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2k
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Do we have equivalent standards for all UL standards under IEC?
As per the image, it looks like there will be an alternative standard in IEC with respect to every UL standard?
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2
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442
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United Kingdom Split Phase Transformer / Centre Tapped Earthed (CTE) / 55V - 0V - 55V - How do you wire the connector?
I'm working on a weird project which involves making a custom cable for a British CTE Transformer. For those not in the know, these transformers are typically used at jobsites to provide 110V power. ...
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IEC grounding and bonding standard
Is there an equivalent standard in IEC such as UL 467 or IEEE 837 which talks about the various test procedure for bonding clamps? Is IEC 61914:2015 similar to UL 467?
