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Questions tagged [insulation]

An insulation or insulator, is a barrier of non-conductive material around electrical conductors and other circuit-components like resistors, capacitors, IC etc.

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Safety considerations for designing Mains Voltage Sensing Circuit

I'm looking to design a circuit to measure AC mains voltage and current for protection purposes. I'm considering using the ADS131E0 ADC by Texas. The IC is made with power-line monitoring in mind. On ...
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In a high voltage insulator with multiple discs, when is it advantageous to gradually increase their diameter?

What engineering considerations go into gradually increasing the diameter of dielectric discs for high voltage standoff insulators? I recall seeing high voltage insulators that had small diameter ...
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How to track down <100µA earth leakage on DC rails

On our subsea robot, we have an isolated power supply (converting 3-phase AC into 320 Vdc). For security reasons, we have a line monitor monitoring the resistance between protective earth and both 0 V ...
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Two-point probe volume resistance how to measure without guard?

So I have measured the surface resistance of a highly insulative material using a Megger MIT 420/2 and a two-point probe. But how would I go about measuring volume resistance? The Megger has no guard ...
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Need USB C cable / connector insulation voltage....and ESD on shield, will impact the internal signals

Any one know how much voltage the standard USB C cable insulation can withstand?..Also want to know shield to internal conductor insulation..If I apply ESD on the connector shield, will it impact the ...
NICEGUY NICEGUY's user avatar
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What type of wire do you recommend for "breadboard jumpers" where the insulation doesn't melt?

Every kind of 24AWG solid core wire I've gotten from Amazon over the years has this same problem. If you want to have lovely neat organized breadboards/perf board circuits, you try to bend the wire to ...
AJ_Smoothie's user avatar
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Risk of Insulation Tester / Megger damage from voltage breakdowns?

I've purchased an insulation tester capable of outputting 5kV and measuring resistance up to 1000 GΩ, as detailed in the manual available here. While my tests are not prone to significant breakdowns, ...
15 Volts's user avatar
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EV charger individual cable insulation

Are the internal conductor strands inside the Level 1, level 2, level 3 EV chargers bare or do they have a coat of insulation? I know the conductor strands combined as a wire have a sheath of rubber ...
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Can ML240 polyimide magnet wire handle 50kV when used in inductors?

I have built ~2mH inductors wired on air core plastic bobbins from AWG26 ML240 polyimide magnet wire and tested them at ~25kV. They seem to work fine without shorting through the polyimide insulation....
Robert Francis Jr's user avatar
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Is there a way to do a high voltage insulation check on a wire without grounding it?

So far we are using a common HV tester to check the insulation (green) of a wire: It has coal brushes (thin blue) at 1000 V, the wire core (orange) is PE. Short-circuit or leakage create a fault ...
Joe's user avatar
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Percentage difference of winding measurements

I am trying to learn more about the proper winding measurement of power transformers. In this regard I am following this tutorial https://www.youtube.com/watch?v=3HIEIoa4NKA&list=LL&index=2. ...
k1gabitzu k1gabitzu's user avatar
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Megger terminals clarification

I saw that some meggers inject the test voltage / current from the - (minus) terminal while do this from the + (plus) terminals (don't know why, it probably depends on the manufacturer?) Currently I ...
k1gabitzu k1gabitzu's user avatar
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Best way to heatsink many exposed copper polygons, avoiding electrical shorts

I'm working on a special type of lamp that uses 10 high-power SMD LEDs and 10 low-power TH LEDs. The heat dissipation will be an issue, so almost the entirety of the PCB is copper pours for the SMD ...
anrieff's user avatar
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What is the purpose of pin row header standoffs (the small legs or ribs on bandoliers)?

Image of header documentation from Samtec with the standoff sections highlighted in yellow - note the lengths shown here are reverse usual headers i.e. the pin's short side is usually by the standoffs ...
BanalMoniker's user avatar
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Understanding insulation resistance in a transformer

I looked for a schematic that shows the insulation resistances in a transformer. I could not find any, so I drew what I think is right: I read that there's insulation between the primary and ...
Edward Josef's user avatar
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2 answers
2k views

Insulation resistance or isolation resistance?

is there a difference between "isolation resistance" and "insulation resistance"? What is the correct term? I have a definition: "Electrical resistance with an often high ohm ...
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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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Why are conductive chassis double insulated appliances allowed in the UK?

MacBooks are infamous for 'buzzing' to the touch while charging. If another (properly Earthed) laptop touches one, it can flicker the screen or shut down. If I plug one of these same properly Earthed ...
OJFord's user avatar
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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.
Jelle Westra's user avatar
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2 answers
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Is the plastic sheath on wire nessesary? [closed]

My brother added a breaker and ran a line of wire, but he stripped off the plastic sheath leaving bare copper wire in the attic. Is this safe?
Bev Sweet's user avatar
4 votes
1 answer
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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. ...
Harsh's user avatar
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Should I strip insulation from the copper wire when forming an antenna?

I'm forming an antenna from insulated copper wire. Insulation property is to block electric field, if I am not mistaken. Should I strip the insulation from the wire to allow better receiving of radio ...
gavenkoa's user avatar
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1 answer
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What determines the voltage rating of a cable, and why do some cables have \$U_0 = U\$ while others have \$U_0 < U\$?

Just as an example, let's consider two cables, with voltage ratings being respectively 300/300 V and 300/500 V. My understanding is that voltage rating is an indication of the quality of the ...
denny baldini's user avatar
9 votes
2 answers
940 views

What is a correct method to measure safe maximum voltage of a PCB?

I have a small (24 x 15 mm) PCB for a custom connector. It is intended for low voltage (< 48 VDC) applications, but I am interested in measuring it in order to provide customers a reasonable ...
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30ga Kynar wire-wrap insulation withstand rating?

I commonly use 30ga Kynar (Polyvinylidene Fluoride, PVDF) wire for PCB <=24 VDC repairs. But can it be used to repair 120 VAC signal wires? Strangely, vendors do not seem to publish a voltage ...
rdtsc's user avatar
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2 votes
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Can insulation resistance be properly measured at low voltages such as 20 V?

I'm attempting to better understand the process of measuring insulation resistance. As you will infer, I am not at all familiar with this measurement. We have a connector prototype that we have ...
JYelton's user avatar
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2 votes
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367 views

What is the best way to transmit 1 kW (power supply) to a tethered drone so that the cable thickness and weight is minimized?

I am delivering 1 kW power to a tethered drone. To minimize the wire weight and maximize maneuverability, I would like to keep the wire as thin and lightweight as possible. The motors on my drone have ...
Pragy Agarwal's user avatar
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76 views

Double insulated PSU to replace batteries

I am building a small power supply with a linear regulator that can be used in place of 9 V blocks. Like a battery, it needs to be floating and hence I want to build it according to double insulated ...
ecclectrics's user avatar
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Choosing a liquid binder for a conductive paste

I want to make a conductive paste using graphite powder mixed with a liquid binder. The idea is the liquid binder dries/cures and the grains of powder are bound together to form a conductive pathway. ...
EddieP's user avatar
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Insulation safety ratings (working and withstand voltage) of fiber optics cables

I'm trying to build a high voltage optocoupler to implement galvanic isolation between a high voltage supply and its control signals. Since the working voltage is several kilovolts, it's beyond the ...
比尔盖子's user avatar
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How do stacked cylindrical discs work as insulators when there is metal in their center? [duplicate]

A couple of previous questions here asked about the purpose of stacked cylindrical discs and the answers indicated they are insulators that prevent arcing. We recently found a broken section of these ...
Michal Kucera's user avatar
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1 answer
85 views

What is the insulation material on the wire for this PCB transformer? [closed]

Circled below: It's a bit wrinkled. Can anyone tell just from the texture and color?
FlakR's user avatar
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How to distinguish different temperature wire insulations?

Wire insulations have different temperature ratings: 80°C 90°C 105°C 125°C 200°C These ratings can result in different current ratings for the same wire gauge. Are there ways to distinguish ...
FlakR's user avatar
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2 answers
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Would an inductor work differently under a different dielectric environment?

I am talking about these common rounded inductors with a metal core that you would find on PCBs. Would the operation be different in, say, mineral oil vs. air? These are two different dielectric ...
FlakR's user avatar
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PTC Heating Element Watt and Insulation Film | Hot Melt Glue Gun

Question 1 If two glue guns of 20 watts and 40 watts are receiving direct current from the electric board (no adapter). Then what makes one gun 20 watts and the second one 40 watts. Is it related to ...
tangiblephysics's user avatar
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1 answer
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White insulating sheets inside power supply

Does anyone know what this kind of sheet is called? I presume the purpose is for electrical insulation. The one in the picture is found on a fan inside a power supply.
FlakR's user avatar
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Insulation monitoring device for electric vehicle

Good day to all! I am planning on designing an electric vehicle architecture from scratch. My main DC bus voltage is 400 V. However, I have got different voltages in my system. I have got a 600/400 V ...
gr3en_apple's user avatar
1 vote
2 answers
767 views

What Stops the Windings on an Electric motor From Shorting with Each Other?

What stops the windings from shorting with each other? Are the windings insulated when the copper is still not bent, then the insulated copper is bent into the winding shape?
itisyeetimetoday's user avatar
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225 views

Landing a Thermocouple on a surface with voltage present

I am connecting multiple K-type TCs (thermocouples) to an electric engine prototype. I have had a problem with the TCs having up to 150 volts on them when the engine is running. I don't know the ...
Greenhorn's user avatar
1 vote
1 answer
1k views

Difference between Working Voltage and Isolation Voltage?

I am building a board to collect data from a 2000V system. The board is going to be powered from a USB port on a laptop and data collected directly into the laptop. I am looking at Isolated 5Vto5V ...
AQUAMAN's user avatar
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2 votes
0 answers
62 views

Electric shock through thick rubber tube filled with coolant and carrying a high voltage wire

I have two Litz wires coming out of a coil. The coil is driven with short pulses of 20 kHz sinosoidal voltage with a peak of 1.4kV. Each Litz wire is insulated by 3 thin layers of mylar sheets in ...
Khaled Nasr's user avatar
1 vote
1 answer
2k views

How much voltage can one layer of a common black electrical tape block? [duplicate]

Wikipedia says just "Low voltage, phase B". The tape I bought has no specification about such property on the package. About how much voltage can one layer of such tape block? If one layer ...
Damn Vegetables's user avatar
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1 answer
62 views

Is asymmetric insulation resistance a sign of AC appliance failure?

I tracked down an AC appliance (a dishwasher) which started tripping my home current circuit breaker (RCD). I happen to have a professional insulation resistance meter and I was able to measure about ...
miroxlav's user avatar
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1 vote
2 answers
194 views

How do you pass Insulation Testing when your load is low impedance?

This is probably a silly question but I read that for class I equipment I need to perform insulation resistance tests and it must be under 1 megaohm. My understanding is that one of these tests ...
MMmmm's user avatar
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0 answers
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Why is insulation resistance is bad when absorption Ratio ≈ 1 and insulation resistance is good when absorption Ratio >1.25 or 1.3?

i will do absorption Ratio (AR) test for transformers in my job,and i know how to calculate the absorption Ratio AR=\$ \frac{R_{60}}{R_{30}}\$ \$ R_{60}\$=Insulation Resistance after 60 second test \$ ...
user16266657's user avatar
2 votes
2 answers
308 views

What is the standard PVD coating for electrical insulation purposes?

I want to insulate some copper parts with a thin coating. I am interested in a physical vapor deposition (PVD) process, but I’m not sure if PVD is suitable for the deposition of an electrically ...
EddieP's user avatar
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0 answers
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Insulation and losses In transmission line

Why do we consider only P=V.I In AC transmission while designing the insulation of transmission line not the equation P=V^2/Z and consider this equation in determine the insulation in DC transmission ...
Sudhanshu Ranjan's user avatar
1 vote
2 answers
876 views

Electric-grade gel / silicone to provide physical protection for circuit boards from damage

Not looking for a brand or product (unless allowed to ask) just the generic name for electric-grade gel / silicone that can be poured on the circuit board or embed the circuit-board in it. It would ...
TommyS's user avatar
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6 votes
3 answers
637 views

What's the right replacement for vintage "glass cloth insulation" that transfers heat in Variac?

I ripped apart a broken 1950s-era Variac autotransformer to diagnose an internal short in the core, and found a layer of gooey insulating fabric mat between the coil/taps and the mounting plate: The ...
BZo's user avatar
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0 votes
1 answer
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Trying to understand practical applications for bonded metal laminations & insulated epoxy coating [closed]

I am trying to better understand practical applications for bonded metal laminations and insulated epoxy coating. I started a new job at a company that does this and I am so lost. Any insight would be ...
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