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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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 ...
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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. ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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.
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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?
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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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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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. ...
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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 ...
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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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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?
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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 ...
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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 ...
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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 ...
EnaVodo's user avatar
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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.
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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
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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?
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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
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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 ...
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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
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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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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 ...
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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 ...
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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
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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 ...
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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
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562 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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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 ...
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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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Strain gauge installation tester vs. insulation tester

An insulation tester (or a Megaohmtester) costs in the range of 500-1k USD and can measure up to G-Ohm and more in resistance. Even a big brand tester like Fluke 1587 costs under 1k. Not saying they ...
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Delayed insulation failure of DC barrel jack

Recently I had to replace a male DC barrel jack that connected a string of LEDs to a driver. Unconnected, I measured 100 VDC out of the driver. The male jack I salvaged from an old 12 VDC power ...
J Physics FM's user avatar
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4 answers
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Is solder mask a valid electrical insulator?

I had some PCBs manufactured prior to ordering all of my components :-( It turns out that the surface mounted 1W LEDs I'm going to use have the heat slug connected internally to the LED's +ve terminal....
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Estimating VAC rating from VDC rating

I have encountered several terminals, sockets, cables, and similar components which are rated in either DC or AC voltage, but not both. I sometimes want to use an AC rated part with DC or vice versa. ...
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How would you apply high voltage on a piece of dielectric making sure breakdown does not occur?

Say you have a piece of dielectric with a breakdown electric field, BDE. For some experimental requirement you have to apply an electric field, E > BDE, across the piece of dielectric without ...
ExpGuy's user avatar
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Distribution of charges in an electrostatic study

I have a question concerning the capacitive coupling between two conductors. The capacitance C between the two is only a function of the diameter of the 2 studied conductors, the insulation thickness ...
Wallflower's user avatar
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Diagnosing voltage reading on battery pack. Possible Insulation leakage?

With reference to this question I asked the other day: How can I measure a voltage between two conductive surfaces that are completely isolated? There was a good answer there so I didn't want to ...
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Which insulating tape and when?

There are quite a few tapes out there, from the plain black electrical tape to different color variations to Scotch 33+, 77, 88 to Kaptons (polyamide), I have also seen some velcro type wraps which ...
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Any electric insulation material that is great heat conductor even 300°C?

Is there any good electric insulation material or tape that is also great heat conductor even 300°C and above. I wish to wrap nichrome wires with this material in creating a water cup heater. Thanks.
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