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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. ...
vionyst's user avatar
  • 856
1 vote
2 answers
74 views

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 ...
Never's user avatar
  • 100
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0 answers
32 views

Industrial product IEC 61000-3-2 compliance

I have a question related to IEC 61000-3-2 standard for current harmonics limits. I am working on an industrial product rated for 500W that connects to the grid (220VAC). The standard states that ...
Ultra67's user avatar
  • 485
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0 answers
47 views

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 ...
Mariana's user avatar
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0 answers
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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-...
Kostas Severus's user avatar
1 vote
0 answers
61 views

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 ...
Explorex's user avatar
  • 408
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0 answers
61 views

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 ...
chx's user avatar
  • 368
1 vote
0 answers
33 views

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?
Marty Schrader's user avatar
1 vote
1 answer
391 views

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 ...
Navoda Punchihewa's user avatar
4 votes
2 answers
204 views

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 (...
DaSnipeKid's user avatar
2 votes
1 answer
89 views

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 ...
DaSnipeKid's user avatar
1 vote
1 answer
125 views

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 ...
Manoj Vignesh T's user avatar
1 vote
0 answers
53 views

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 ...
user14665305's user avatar
1 vote
0 answers
574 views

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 ...
Carton_'s user avatar
  • 145
0 votes
1 answer
158 views

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 ...
Gopal's user avatar
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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 ...
YOYO's user avatar
  • 11
3 votes
3 answers
414 views

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 ...
DaSnipeKid's user avatar
1 vote
4 answers
230 views

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 ...
DrSmokeWrench's user avatar
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0 answers
63 views

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.
Jelle Westra's user avatar
4 votes
1 answer
214 views

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. ...
Harsh's user avatar
  • 103
0 votes
0 answers
809 views

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 ...
LoukasGr's user avatar
0 votes
0 answers
136 views

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 ...
Steven_25's user avatar
6 votes
2 answers
1k views

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}\$. ...
DaSnipeKid's user avatar
2 votes
2 answers
6k views

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 ...
Mark Hofmeister's user avatar
1 vote
0 answers
238 views

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. ...
KarlKarlsom's user avatar
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0 votes
2 answers
77 views

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 ...
cm64's user avatar
  • 2,203
2 votes
1 answer
377 views

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 ...
jan019's user avatar
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0 answers
128 views

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 ...
MMmmm's user avatar
  • 49
1 vote
1 answer
5k views

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 ...
user139731's user avatar
1 vote
1 answer
6k views

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 ...
Jimmy Alfred's user avatar
1 vote
0 answers
80 views

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 ...
Mayank Saxena's user avatar
3 votes
0 answers
151 views

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 ...
MichielB's user avatar
  • 151
0 votes
2 answers
2k views

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 ...
Sandaru Akalanka's user avatar
1 vote
1 answer
168 views

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 ...
nikhil valiveti's user avatar
2 votes
1 answer
2k views

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's user avatar
0 votes
2 answers
287 views

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. ...
NuclearDude's user avatar
1 vote
0 answers
144 views

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?
Electronic Curious's user avatar