Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [iec]

30 questions
6
votes
2 answers

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}\$. However, it seems that determining the value of \$Z_k\$…
DaSnipeKid
  • 253
  • 1
  • 10
4
votes
2 answers

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 (contacts such as busbar joints, SCPD joint, or any…
DaSnipeKid
  • 253
  • 1
  • 10
4
votes
1 answer

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. Our pipette is powered by a rechargeable battery…
Harsh
  • 81
  • 5
3
votes
3 answers

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 specific values for all the manufacturers. And…
DaSnipeKid
  • 253
  • 1
  • 10
3
votes
0 answers

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 something to do with the user being closer to a…
MichielB
  • 151
  • 2
2
votes
1 answer

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 temperature rise states about the constant value. It…
DaSnipeKid
  • 253
  • 1
  • 10
2
votes
2 answers

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 outlet to the corresponding wires of the transformer,…
Mark Hofmeister
  • 41
  • 2
2
votes
1 answer

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 lighting). The PCB will be placed in a box with IP65…
jan019
  • 43
  • 5
2
votes
1 answer

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?
nikhil valiveti
  • 47
  • 5
1
vote
1 answer

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 Australia as I cannot find any polarised C7 plugs with…
Navoda Punchihewa
  • 11
  • 2
1
vote
1 answer

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 130°C. Why is the absolute temperature mentioned…
Manoj Vignesh T
  • 11
  • 2
1
vote
0 answers

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 load? From my understanding these type of…
user14665305
  • 109
  • 3
1
vote
0 answers

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 cannot comply with UL2556 VW-1 but with UL1581…
Carton_
  • 135
  • 7
1
vote
0 answers

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 1000V (4000, 6000, 8000, 12000) Ex) DC 1050V,…
YOYO
  • 11
  • 2
1
vote
4 answers

Can I convert a stereo receiver's hard-wired two-prong power cord to an IEC C7?

enter image description hereenter image description here 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…
DrSmokeWrench
  • 67
  • 6
1
2