Picture source: Facebook https://www.facebook.com/share/p/1DrRjhJH2r/

I have been reached that If you should not use a knot for cable strain relief.
⚠️ Important: If this is a 230 V / mains-powered device, proper mechanical strain relief is mandatory for safety and compliance.
A knot is not a safe strain-relief method, especially for electrical cables.
If this is for mains power, lab equipment, or a commercial product, knots are simply not acceptable.

Here’s why it’s considered unsafe ❌:
Uncontrolled bending radius → damages conductors over time
Stress concentrates at one point instead of being spread out
Insulation can be crushed or cut, especially on flexible cords
Not compliant with electrical standards (IEC, UL, etc.)
In mains voltage, a pulled knot can still transfer force to terminals
Proper strain relief must mechanically clamp or grip the outer jacket of the cable and transfer pulling force to the enclosure, not the conductors.

✅ Safe alternatives:
Cable gland (PG/M thread, rubber compression)
Strain-relief bushing / grommet
Screw-mounted cable clamp
Zip tie + fixed anchor (inside enclosure, jacket only)

Here is an analysis of each method:

1. Cable Gland (PG/M thread, rubber compression)

This is one of the most professional, secure, and robust methods for cable entry and strain relief.

How it works safely: A cable gland consists of a threaded body, a rubber or neoprene compression seal (grommet), and a compression nut. As you tighten the nut, the seal compresses radially around the cable’s outer jacket. This action creates both a strong mechanical grip for strain relief and a watertight/dust-tight seal (often rated to IP68).

Best Practices for Safety:

Correct Sizing: It is crucial to select a gland whose sealing range matches the exact outside diameter of your cable. A loose gland offers no protection, while an undersized one can damage the cable jacket.

Proper Tightening: Follow the manufacturer’s torque specifications. Under-tightening can lead to cable slippage, while over-tightening can crush the cable’s internal insulation.

Material Selection: Choose the right gland material for the environment. Plastic (nylon) is common for general indoor/outdoor use, while metal (brass, stainless steel) is preferred for industrial or hazardous locations for added durability and electromagnetic compatibility (EMC).

2. Strain-Relief Bushing / Grommet

These are commonly used in consumer electronics and appliances for a cost-effective and reliable solution.

How it works safely:

Strain-Relief Bushing: This is typically a two-part nylon component that clamps onto the cable and then snaps into a pre-punched hole in the enclosure wall. The geometric shape of the bushing, once snapped in, prevents it from being pulled back through the hole, effectively anchoring the cable.

Grommet: A simple rubber grommet protects the cable from chafing against the sharp edges of a metal hole. While it provides some friction, it is not a primary strain relief device on its own. However, some “strain-relief grommets” are designed with an internal membrane that grips the cable.

Best Practices for Safety:

Match to Cable and Hole: You must use a bushing designed specifically for the cable’s profile (round or flat) and dimensions, as well as the panel hole size and thickness. A poor fit will result in failure.

Installation Tool: For high-volume applications, a special assembly tool is often recommended to ensure the bushing is fully and correctly compressed and seated without damaging the cable.

3. Screw-Mounted Cable Clamp (P-Clip / Saddle Clamp)

This is a simple, mechanical method widely used in automotive, industrial, and general wiring applications.

How it works safely: A metal or plastic clamp, shaped like the letter “P” or a U-saddle, is placed over the cable and secured to a fixed surface inside the enclosure with a screw. The clamp holds the cable jacket firmly against the surface, preventing movement.

Best Practices for Safety:

Correct Size: The internal diameter of the clamp must match the cable diameter closely. A clamp that is too large will not grip, and one that is too small will pinch and damage the cable.

Cushioning: For metal clamps, choose a version with a rubber or vinyl cushion lining. This protects the cable jacket from abrasion and distributes the clamping force more evenly, preventing damage to the internal conductors.

Secure Anchoring: Ensure the screw is fastened securely into a solid part of the enclosure so the anchor point itself does not fail under tension.

4. Zip Tie + Fixed Anchor (Inside enclosure, jacket only)

This is a versatile and common method, especially for retrofitting or custom wiring, but it requires careful execution to be safe.

How it works safely: A zip tie (cable tie) is used to bundle the cable to a fixed anchor point inside the enclosure. The anchor can be an adhesive-backed mount, a screw-mount base, or a dedicated tie-down point molded into the enclosure.

Best Practices for Safety:

Grip the Jacket Only: The most critical rule is to only secure the outer jacket of the cable. Never place a zip tie around the individual insulated conductors after the jacket has been stripped. This can crush the insulation and cause a short circuit.

Do Not Over-Tighten: Tighten the zip tie by hand just enough to prevent the cable from sliding. Using a tool to over-tighten can easily crush the cable’s internal structure, leading to long-term failure.

Use Correct Anchors: Adhesive anchors can fail over time, especially in warm environments. For a permanent and safe solution, use a screw-mounted anchor base secured to the enclosure wall.

Anchor Location: Place the anchor as close as possible to the point where the individual wires break out of the jacket to minimize movement at the terminations.

Examples:
This YouTube video, it’s a great visual guide on how to properly install a cable gland, which is one of the most secure methods
Strain Relief Connectors… New design for more flexibility

I hv been seeing circuits like this i will be wondering what a hell are they publishing like this without shame !

Dangerous, do not use !

This is what I call an “automatic house ingnitor circuit”

Lithium battery exploder circuit

That looks like a one way ticket to frying your USB controller, and a Lithium battery that may burst in to flames.

No over voltage protection, no Over-current protection, the only resistor is on the LED. That is an express way to burning someones house down.

I would not recommend this circuit. The USB 3.0 interface will supply 5V. There will be a 0.7 V drop across the diode, so you will be trying to charge the 3.7 V Lithium battery with 4.3 V. The Voltage to charge the battery should not exceed 4.2 V. I recommend you use a proper BMS to control the charging of the battery. The USB voltage can go higher than exactly 5V, as the USB voltage range varies, with traditional standards being around 5V but with a range of approximately 4.4V to 5.25V.

A lithium-ion battery can explode or catch fire due to a phenomenon called thermal runaway, which is a dangerous, self-perpetuating chain reaction that causes a rapid increase in temperature. This is most often caused by internal short circuits from manufacturing defects or damage, overcharging, or exposure to high temperatures. While a full explosion is possible, more often it results in the battery venting hot gases and flames through a safety valve.
Video: Here’s what happens when a lithium ion battery explodes

After some research on some product information pages and Wikipedia Network Isolator page I found out that there are some special cases where there are sensible reasons to use such extra isolation device on Ethernet network. After some more searching, I also found products designed for industrial applications and audio applications.

PATIENT PROTECTION
Galvanic isolation of the Ethernet interfaces on medical electrical equipment or systems
for which patients must be protected from harmful leakage currents in line with standards.

APPLIANCE PROTECTION
Protection of particularly valuable devices from ripple voltages and surges from the edge of the network.

MEASUREMENT TECHNOLOGY
Protection of electrical measurement and monitoring equipment from external voltages and interference voltages from the
Ethernet cabling.

POTENTIAL DIFFERENCES (BUILDING TECHNOLOGY)
Potential equalisation currents are prevented in computer systems connected via an Ethernet
cabling over greater distances.

AUDIO
Reduction of low-frequency AC voltages (mains ripples), which are caused by the network connection, to an imperceptible level.

Medical applications

Network isolators are used in the medical industry to protect patients against leakage currents. IEC standard IEC 60601-1 (3rd edition) specifically deals with medical electronic and electrical equipment and systems, and classifies non-medical devices as potential hazard sources. Network isolators work to remove this hazard, by electrically disconnecting medical devices from a network. They are often installed in the medical field in conjunction with isolation transformers, which serve to protect the patient from electrical faults. The international standard IEC 60601-1 Medical Electrical Equipment (3rd edition) specifies stringent criteria on the safety and isolation of medical devices. Very many medical institutions use Ethernet isolators for electrical safety and to keep equipment interference free. Medical-grade Ethernet isolators must follow strict regulations concerning the isolation level that an Ethernet isolator provides. Isolators marketed to meet European Medical Device Directive (EN6060-1) typically have isolation level of 4kV or higher.

Industrial applications

Network isolators have industrial applications in overcoming the problems of differing ground potentials across networks, or between network components for example to stop shield currents on shielded Ethernet cable (ground loop currents) and on electrical testing facilities where higher that normal office environment electrical disturbances are present. There are also uses in electronics testing  systems where dangerous voltages are present.

Ethernet Isolator combines intrinsically safe energy limitation and galvanic isolation page tells that the FieldConnex® Ethernet Isolator combines intrinsically safe energy limitation and galvanic isolation into one product. Now Ethernet connections are plug and play in Ex-Zone 1. Intrinsically safe Ethernet Isolator EI-0D2-10Y-10B product provides galvanic isolation according to EN50020 for 10 BASE-T/100 BASE-TX. It contains active electronics and needs a power source to operate.

Audio applications

Ground loops and high frequency noise have known to cause all kinds of issues with sensitive audio systems. Especially people tuning their HiFi systems are interested could Ethernet connection be improved in some way. Because almost all the audiophiles would have experienced of tuning their own audio system with variety of cables or accessories in order to enhance the music sound from their treasured audio systems, some special HiFi equipment manufacturers have seen market for expensive Ethernet isolators for HiFi applications. So called ‘audiophile’ grade ethernet cables have made inroads into specialist audio dealers.

Audio Stream Ethernet Accessories and Cables page has information on several special (expensive) accessories that are claimed to provide improvement when used with HiFi equipment. In Ethernet isolation sector the page lists SOtM iSO-CAT6 Ethernet isolator. SOtM iSO-CAT6 Ethernet isolator product page claims that noise interference created by LAN port has enormous effect to system sound and SOtM iSO-CAT6 may offer certain varying sound improvement (for other views check reviews at 6moons and avrev). SOtM iSO-CAT6 manual says that this product provides isolation 1500Vrms, 0.5mA, 60sec (same level as normal Ethernet cards).

Are the isolators really needed in audio system? Maybe not in most cases (but there can be some special cases where extra isolation can have some effect). By default the ethernet ports are isolated with transformers. However – ground loops from shielding still can exist if you use shielded cables. If you are worried on ground loops on audio system, I recommend to use unshielded Ethernet cables, so you get no ground loop. If you are really paranoid on isolation, isolate the audio with a fiber optic cable. Some people who have written on their experiences have found out no difference on copper, isolated copper or fiber on sound quality. This no difference will also apply to special Ethernet cables: The use of solid core verses stranded or gold verses silver for the conductors for this link in particular is just putting lipstick on a pig. Again, this is digital side… The likelihood of there being a genuine difference rather than a psychoacoustic cause for the described difference is much, much lower given known physics.

How Ethernet Isolators Work

An Ethernet isolator separates the electrical currents of multiple devices: it allows the Ethernet data signals to pass without allowing the two circuits to physically contact each other. The Ethernet isolator is basically just several 1:1 Ethernet transformers put between the RJ-45 connections (two needed for 10/100 Mbit/s Ethernet, four needed for 1 Gbit/s Ethernet). Typically all those transformers are built into one transformer module similar to ones used in Ethernet cards and switches. Such isolator consists of a small PCB at the back panel with two RJ45 connectors and a LAN transformer in between. This would provide an additional 1500V to 4000V of isolation depending on the transformer chosen.

Network isolators are commercially available in various designs. Medical-grade Ethernet isolators must follow much stricter regulations concerning the isolation level that Ethernet isolators for industrial uses.

Ethernet isolators are typically constructed using the same technique as normal Ethernet port. Ethernet specification needs magnetic transformer coupling between RJ45 connector and electronics. Most modern Ethernet ports with MDIX functionality (auto-detect direct or cross-connect) use 1:1 transformers optimized for Ethernet frequencies (frequency range depends on line speed) and impedance (100 ohms)  for all used signal pairs.

Transformers offer a very good common mode rejection: A transformer only “sees” the voltage accross its windings, not the common voltage both ends of the winding are driven to simultaneously. You get a differential front end without a deliberate circuit, just basic physics.

An Ethernet isolator could be basically built using one such transformer module (contains 2 or 4 transformers in one case) that is just wired between two RJ45 connectors. Standard Ethernet transformers provide typically 1500Vrms isolation. If higher isolation level is needed, a suitable special transformer with improved isolation specification needs to be manufactured. For example medical isolator can isolate the data AND the shield up to 5.000V. The nic transformers only isolate the data up to 1.500V. Here is picture of MI 1005 E Medical Built In Isolator showing that there is just transformers (inside black box in the center) and two RJ45 connectors.

Isolation is a very good idea on communications systems that are linking lots of different hardware over a wide area: You don’t want fault current/voltages in the mains wiring or devices to spread onto your communications wiring.

Ethernet transformer links:
http://www.haloelectronics.com/products/lan/ethernet/
http://www.mouser.fi/new/molex/molexRJ45jacks/
http://www.mouser.fi/new/halo-electronics/halo-ethernet-transformers/
https://www.eeweb.com/company-blog/microchip/migrating-from-the-lan9115-to-the-lan9210/

Links to more information:
http://www.diyaudio.com/forums/pc-based/154048-ethernet-galvanic-isolation.html
http://www.bb-elec.com/Learning-Center/All-White-Papers/Ethernet/Power-over-Ethernet-PoE.aspx
http://hackaday.com/2010/10/26/ethernet-connection-using-capacitive-coupling/
http://www.youritronics.com/magnetic-less-ethernet/

Some product links:

I have found those with Google search. I have not used any of those or recommend them.
http://industrialcomponent.com/baaske/2006633.html
http://industrialcomponent.com/baaske/ethernet-isolation.html
Ethernet Data Isolator – 10BASE-T/100BASE-TX
http://industrialcomponent.com/baaske/2006633.html
L-com 10/100/1000 Ethernet Data Isolator (EN60601-1 Compliant) provides isolation up to 4 kV
Bourns 360 V dc 3kA 1500 Isolated Ethernet Protector, Wall Mount Mounting is an Ethernet surge protector product that also promises to provide 5 kV isolation for 10/100/1000 Mbit/s Ethernet.
EMO EN-100C :: Network isolator for PCB mounting is intended for integration on the PCB of the device being protected. The devices in the EN-100-series meet the requirements of IEC 60601-1 (3rd edition) and IEC 60601-1-2 for medical settings
Phoenix Contact Network isolator – FL ISOLATOR 100-RJ/RJ – 2313931 is a passive passive network isolator for electrical isolation in Ethernet networks up to 4 kV and speeds of up to 100 Mbps.
https://www.mtl-inst.com/images/uploads/datasheets/is_ethernet/9468-ET.pdf
http://www.mmcchina.com/Upload/whitepaper/MMC_Whitepaper12EN.pdf
http://industrialcomponent.com/baaske/ethernet-isolation.html
http://industrialcomponent.com/baaske/2006633.html
http://www.baaske-medical.de/media/content/Datasheet_MI1005_MI1005E.pdf
http://industrialcomponent.com/baaske/2006633.html
https://www.dustinhome.fi/product/5011222413/rj45-network-isolator-6kv
https://www.dxengineering.com/parts/dxe-iso-plus-2
https://www.phoenixcontact.com/en-pc/products/network-isolator-fl-isolator-1000-rj-rj-2313915

Sources:
http://www.tech-faq.com/ethernet-isolator.html
http://electronics.stackexchange.com/questions/180415/ethernet-3000v-isolation
http://www.mouser.fi/new/halo-electronics/halo-ethernet-transformers/
http://www.diyaudio.com/forums/pc-based/154048-ethernet-galvanic-isolation.html
http://www.6moons.com/audioreviews2/sotm2/1.html
http://www.avrev.com/home-theater-accessories/acoustics-eq-room-tuning/sotm-iso-cat6-lan-filter-and-tx-usbhub-review-3.html
http://www.computeraudiophile.com/f22-networking-networked-audio-and-streaming/audiophile-ethernet-cables-13798/
http://www.computeraudiophile.com/f22-networking-networked-audio-and-streaming/ethernet-cables-audiostream-test-17713/
http://electronics.stackexchange.com/questions/27756/why-are-ethernet-rj45-sockets-magnetically-coupled/27762
http://www.diyaudio.com/forums/pc-based/154048-ethernet-galvanic-isolation.html

According to the Northern Lights forecast of the Finnish Meteorological Institute, geomagnetic activity will remain higher than normal during the beginning of the week. The solar wind is still fast over the earth, and mass coronal eruptions that probably hit the earth have been emanating from the sunspot region that caused the storm every day. This solar activity involves the release of energy from the sun that travels through space and eventually reaches Earth. Solar radiation storms occur when a large-scale magnetic eruption, often causing a coronal mass ejection and associated solar flare, accelerates charged particles in the solar atmosphere to very high velocities. The most important particles are protons which can get accelerated to large fractions of the speed of light. When that radiation hits the magnetic sphere surrounding the planet, it causes fluctuations in the ionosphere, a layer of the upper atmosphere.

Those fluctuations in the ionosphere can affect communications systems, GPS positioning and electrical power networks.
“Geomagnetic storms can impact infrastructure in near-Earth orbit and on Earth’s surface, potentially disrupting communications, the electric power grid, navigation, radio and satellite operations,” NOAA’s Space Weather Prediction Center said in a release. “SWPC has notified the operators of these systems so they can take protective action.” Aside from brilliant and widespread displays of the aurora, geomagnetic storms can impact infrastructure in near-Earth orbit and on Earth’s surface, potentially disrupting communications, the electric power grid, navigation, radio and satellite operations, the SWPC says. The huge solar storm is keeping power grid and satellite operators on edge. The National Oceanic and Atmospheric Administration says there have been measurable effects and impacts from the geomagnetic storm that has been visible as aurora across vast swathes of the Northern Hemisphere. So far though there have been no reports of major damage.

The last time Earth experienced a Level 5 geomagnetic event, there were power outages in Sweden and damaged transformers in South Africa. Every few centuries the Sun blasts Earth with a huge amount of high-energy particles. The largest known geomagnetic storm in history, known as the Carrington Event of 1859, caused telegraph stations to spark and catch fire. If it were to happen today, it would wreak havoc on technology. A solar storm the size of the Carrington Event could knock out the backbone of the Internet.

Those changes can directly affect satellites and other spacecraft in orbit, altering their orientation or potentially knocking out their electronics. Those changes to the ionosphere can also block or degrade radio transmissions trying to pass through the atmosphere to reach satellites. And they can also prevent radio transmissions from satellites reach earth. SpaceX’s Starlink service warned on its website Saturday morning that it was experiencing “degraded service,” though it didn’t give further details. There has been some degradation and loss to communication systems that rely on high-frequency radio waves.

Since GPS satellites depend on signals penetrating the ionosphere, the geomagnetic disturbance scientists are expecting could affect that critical technology used by planes, ocean-going vessels, and in the agriculture and oil and gas industries. The typical effects of the storm are reduced location accuracy or completely cutting out the GPS location service for some time.

Solar storm managed to shut down farm equipment across US and Canada last weekend. And as the New York Times reports, the storm was particularly devastating for farmers in the US and Canada, whose tractors and other equipment broke down in the middle of planting season — a fascinating and rare example of just how fearsome space weather can become despite our planet’s protective shell. Farm equipment company John Deere’s “StarFire” receivers that combine GPS with other sensor data were hit particularly hard. Tractors that rely on GPS and other navigation tech shut down after the Sun’s ferocious storm, with seed-sowing operations grinding to a halt.

The ionosphere changes could affect shortwave radio transmissions used by ships and aircraft, emergency management agencies, the military and even ham radio operators, all of whom rely on the high frequency radio airwaves. Nothing very serious was reported in the news on those services.

Consumer wireless networks rely on different radio frequencies than the high frequency band, so it appears unlikely that the storm will directly affect cellular service. The impact to cell phones this weekend seemed to have been slim to none. As long as the underlying electrical infrastructure that supports wireless networks remains unaffected, the wireless networks work. The GPS features on your phone also typically use a mix of pure GPS and cellular tower-based location tracking, so even if GPS signals are disrupted, phone users may still be able to maintain a rough location fix.

It was expected that the power grid was potentially at risk. Severe space weather can jeopardize power grids, according to NOAA, whose alert this week said to expect “possible widespread voltage control problems” and that “some protective systems may mistakenly trip out key assets from the power grid.” With a G5 storm, complete blackouts and power grid collapses are possible. A blackout of the electrical grid could have cascading effects for communications and other technologies, including cellphones and the data centers that host websites. Redundancy and resiliency are watchwords of all critical infrastructure providers, so many operators have arranged backup power for essential functions.

Here is the mechanism that causes problems to electrical power grid: These solar caused plasma waves hit the Earth’s magnetic field and compress it, like a balloon that you squeeze with your hands. These magnetic field changes lead to the induction of an electric field in the ground. “This electric field causes currents in our high-voltage lines. These unwanted currents have a negative impact on our energy supply.” “Transformers in particular are adversely affected by low-frequency currents generated by changes in the Earth’s magnetic field. That can lead to big problems.” The way the electrical network is built can affect how much those low frequency magnetic fields can affect it and the used protection systems can affect if critical components can be disconnected before major failures. When protection system work correctly, it can cause short outages. Network operators have strategies for how they proceed in the event of an outage in order to restore supply as quickly and safely as possible. The modern electrical power networks management and remote controlling nowadays uses a lot of communications and networking technology, and if those networks do not work well during the solar event, that can cause delays in restoring power when it gets cut out.

There are examples what could happen: In 1989, a space weather event led to a massive blackout in Quebec, Canada for more than nine hours after geomagnetic fluctuations damaged transformers and other important equipment. In October, an extreme geomagnetic storm stronger than the one predicted for this weekend led to power outages in Sweden and damaged power transformers in South Africa, the SWPC said. In Malmö, for example, in 2003, where solar storms caused a large-scale outage.

This time here were some preliminary indications of irregularities in power systems, but no reports of any major damage. Maybe the power companies were well prepared and/or we were lucky.

Sources:
https://www.epanorama.net/newepa/2022/02/09/space-weather-issues-to-satellites/
https://www.foxweather.com/earth-space/rare-severe-solar-storm-northern-lights-alabama
https://www.cnn.com/2024/05/10/business/sunspots-disrupt-phones-gps-scn/index.html
https://www.iltalehti.fi/saauutiset/a/349a720d-a0dc-4955-9655-65c10a8a73b9
https://www.astronomy.com/science/a-large-solar-storm-could-knock-out-the-internet-and-power-grid-an-electrical-engineer-explains-how/
https://apnews.com/article/solar-storm-northern-lights-power-grid-disruption-eb7fabd1dfbd734a398192bf4c701ca5
https://futurism.com/the-byte/massive-solar-storm-trigger-lights-across-north-america
https://www.gpb.org/news/2024/05/11/the-huge-solar-storm-keeping-power-grid-and-satellite-operators-on-edge
https://en.m.wikipedia.org/wiki/Carrington_Event
https://www.npr.org/2024/05/10/1250515730/solar-storm-geomagnetic-g4
https://www.cbsnews.com/news/severe-geomagnetic-storm-watch-issued-unusual-solar-event/
https://en.m.wikipedia.org/wiki/Carrington_Event
https://www.iltalehti.fi/ulkomaat/a/07d56936-09f4-4410-834f-646b5f7fb634
https://futurism.com/the-byte/solar-storm-shut-down-farm-equipment
https://www.swpc.noaa.gov/phenomena/solar-radiation-storm
https://www.tugraz.at/en/tu-graz/services/news-stories/planet-research/singleview/article/elektrische-netze-stuermische-gefahr-fuer-das-stromnetz0
https://www.kxan.com/news/national-news/what-is-a-g5-geomagnetic-storm/?ipid=promo-link-block1
https://www.firstpost.com/explainers/how-severe-solar-storms-hitting-earth-could-disrupt-communication-lead-to-blackouts-13769676.html
https://www.sfchronicle.com/health/article/geomagnetic-solar-storm-health-effects-19451411.php
https://solar-center.stanford.edu/FAQ/Qflaredest.html

Under the RoHS Directive, in the course of 2023 the production and sale of new fluorescent lighting shall be prohibited within the European Union. From the first of September 2023, T5 and T8 fluorescent tubes will be phased out altogether also in UK.

T8 and T5 fluorescent lamps will be off the market starting from 24 August 2023. In fluorescent lighting the RoHS initiative targets mercury, a common and hazardous substance in linear fluorescent tubes and lamps. Ongoing use of fluorescent will not be illegal, but the sale of new general illumination tubes and lamps will be.

Today, T8 and T5 fluorescent tubes are easily replaced by energy-efficient and environmentally friendly LED light source. The fluorescent freeze-out could bring a revenue boon for LED vendors lasting several years.

The ban introduces the new Single Lighting Regulation 2019/2020 (SLR) and the Energy Label Regulation 2019/2015 (ELR) that covers efficiency and lighting quality of lighting. The SLR no longer distinguishes between lamps, modules and luminaires: instead, it refers only to light sources.

There are also bans in USA. The production and sale of incandescent light bulbs have officially been banned in the United States because of their low energy efficiency. As of August 1, you can no longer purchase incandescent light bulbs, nor are they being manufactured in the United States. This ban also applies to Halogen bulbs and it’s possible that by 2025, Compact Fluorescent Light bulbs (CFL) will also be phased out under the Biden administration’s new standards.2.8.2023 With the sale of incandescent lightbulbs effectively banned in the US, compact fluorescent lightbulbs, or CFLs, are next on the chopping block. From September 2023 a range of halogen, fluorescent and low-performing LED bulbs will be removed from sale. The White House is looking to phase out CFLs by 2025. But some states aren’t waiting that long.

Sources and links to more information:

https://lumenradio.com/stories/eu-ban-on-fluorescent-lighting-are-you-prepared/

T8 and T5 fluorescent lamps will be off the market starting from 24 August 2023.
https://valtavalo.fi/en/yritys/tiedotteet/fluorescent-tubes-to-be-phased-out-in-the-eu/

The amendments were published in the Official Journal of the European Union on 24 February 2022.
https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32022L0284&from=FI

https://www.projectnekton.com/en/information/eu-ban-on-fluorescent-lamps/

https://www.ledsmagazine.com/architectural-lighting/article/14290910/attention-end-users-europe-is-banning-fluorescent-lighting

What is the EU directive for fluorescent lamps?
https://www.projectnekton.com/en/information/eu-ban-on-fluorescent-lamps/

Are fluorescent lights banned in September 2023?
https://www.sparksdirect.co.uk/blog/fluorescent-lamps-tubes-phased-out-september-2023

What light bulbs will be banned in 2023?
https://reviewed.usatoday.com/home-outdoors/features/incandescent-light-bulb-ban-2023-where-to-buy-alternatives

https://www.cnet.com/home/kitchen-and-household/are-compact-fluorescent-lightbulbs-being-banned/

https://www.cbsnews.com/essentials/best-light-bulbs-replace-incandescent-bulbs/

What are the lighting regulations for 2023?
https://professional-electrician.com/features/embrace-new-lighting-regulations-to-power-superior-user-experiences-lutron/

Did you know that figure 8 power cable plug (IEC 60320 type C plug also known as IEC C7) fits into XLR make connector? If it’s round outside, don’t plug an AC cord in, even if it seems to go in. If you do that, you can expect to get disaster result with broken electronics and danger of electrocution. Pins on XLR have the same pitch as mains cable pins. Even the pin size is exactly right to get good connection for feeding mains voltage between XLR pins 1 and 2. Technically it is hot and ground plugged to main live and neutral wires in random order. This is a really bad idea an potentially very dangerous.

There is a good example what kind of damages can happen in this Facebook post that is included here with the permission from the original poster: “Repaired this fatality..it fits bang on! Dude fitted the cable from behind not looking just checking with fingers for right pins…”

This is not the only case where this kind of issues can happen or has happened. There are stories of cd player said bang and let out a nice blue flash. Some claim those accidents to “idiot user” problem, but there are more than that. Mistakes happen when some people do not know too well, are not very careful or need to do plugging in a hurry in environment where they can’t see well and need to go on feeling (for example many live audio setups in dark tight place). It would be better if the mains connector would not easily plug to any other place than mains input socket in he device.

For example Roland RD800 keyboard had the same type issue and the same typo power input was right next to the XLR. Quite a few got blown up so they had to do a recall and they changed the plug on the next version. More information on the recall at https://www.cpsc.gov/Recalls/2014/Roland-Recalls-Digital-Pianos “Hazard:The AC power cord can be connected to the XLR output jacks, posing an electrical shock hazard.”

If you plug the power cord to XLR, what is expected is a bang and let out if some blue flash and maybe some smoke. Depending on which way you plugged in the cord, you could have around 50% change of your equipment metal case to be connected to mains live (which is 230V AC in Europe and 120V AC in USA).

This kind of incidents have been a source of jokes:

You could joke on this incident that here was a DJ that played a banger.

‘Got any AC/DC?’
‘Think I’ve got some AC? I’ll just check’

That’s a bit much for phantom power

So what you’re saying is that a figure 8 cable will work as an unbalanced out in a pinch…
Between GND and HOT… It was only 43dBm (120V AC) or 49 dBm (230V AC) of signal level being fed into the output. It will fry the output electronics.

Back to serious business. Let’s analyze what happens when you plug in IEC C7 plug to equipment XLR. Normally with most common EURO plug to IEC C7 power cable, you can plug in the both ends of the cable freely both ways. Same applies also to most US NEMA to C7 cables as well. So the end result is that you have 50% change that mains power NEUTRAL goes to the XLR pin 1 and LIVE goes to the XLR pin 2. The pin 1 in XLR is the ground pin, that is often connected to the equipment metal case (in some cases it could be isolated or connected through ground lift switch). If there is connection from XLR pin 1 to equipment metal case, that means that the equipment case is now connected to mains neutral wire. Not good but usually not very dangerous (because neutral and ground do not normally have very large potential differences). The XLR pin 2 is the signal hot pin that receives the mains LIVE wire voltage (typically around 120V 60 Hz or 230V 50 Hz). When this high voltage hits typical audio equipment output electronics, the result is that the electronics has more or less fried parts and possibly smoke coming out. Depending on case it could be repairable or whole device could be fried beyond repair. In some rare cases the output could survive the abuse (for example some floating output transformer isolated outputs on some old devices).

The other situation when plug is the other way around is where XLR pin is connected to mains LIVE (120V or 230V AC) and the XLR pin 2 is connected to mains NEUTRAL. In this case if the equipment in question does not have any ground connection anywhere (for example through audio cables to other grounded equipment) the equipment metal case is most probably at mains LIVE wire potential. This is very dangerous, and you could be electrocuted by touching the equipment case like you would be by touching a live wire. In addition to this the equipment XLR output electronics would be fried just like in the previous situation.

The third option is that the plug is plugged just like in previous example: XLR pin is connected to mains LIVE (120V or 230V AC) and the XLR pin 2 is connected to mains NEUTRAL. But the equipment metal case has some other ground connection wired to it (separate grounding wire, grounding through audio cables to other equipment, grounding through metal equipment rack rails etc..). This causes that the LIVE will be shorted to the ground. A lot of current will flow though this ground connection until the circuit protective device stops the current flow (circuit breaker, ground fault interrupter or fuse). When large current flows, you could bear strong bang, see sparks and get some sparking damage to connectors. When the current has been stopped by protective device, you will not get any power and no danger anymore. Your other equipment powered by the same mains circuit will most probably also not get any power anymore. Depending how you plugged the mains cable, how quickly the protective devices cut out the power and some other details, you might or might have damaged equipment and/or audio cables.

I see the possibility of able to plug the main cable to the XLR is a serious design flaw. Pins on XLR have the same pitch as mains cable pins. This is mainly a concern with “prosumer” equipment that use IEC C7 mains connector and has male XLRs. I think there are both equipment designers and whoever originally designed this mains connector for the IEC 60320 standard. IEC C7, that is commmonly referred to as “figure 8″ or “infinity”, was originally designed for domestic audio, video, radio equipment and doubly insulated power supplies. I think that IEC standardization organization made a mistake when they approved XLR mating C7 connector to IEC 60320 standard. At the time of the standard, XLR had been in use for more than a decade for professional audio applications (XLR started around 1950 while IEC standard first version is from 1970′s).

For the product designers is why do you design devices that have both C7/C8 mains input and male XLR connectors? And place them near each other on the back of the device that can be in hard to reach and see place? Making such product designs is stupid and has potential dangers to the user.
Most pro gear use grounded three pin IEC C15/C16 or IEC C5/C6 for mains input or fixed mains cable. With those there is no danger of getting accidentally mains to the XLR connector.

I posted this C7 plug fits to XLR male to my blog years ago
https://www.epanorama.net/newepa/2021/04/29/friday-fun-speaker-to-mains-power-disaster-adapters/

RIFA is Swedish and stands for RadioIndustriernas FabriksAktiebolag, which translates into The Radio Industry’s Manufacturing Incorporated. In German vintage audio forums, these RIFA caps are known as “Knallfrosch”, which translates to firecracker. This is a common problem with vintage computers. Especially in the power supplies. Just get an old machine, turn it on, and boom! Magic smoke! The PME labeled caps were used extensively in older Tektronix switching power supplies. RIFA PME capacitors is pretty much the electronic version of Surströmming. Both come from Sweden, and both explode and stink.

Evox Rifa Metallized Paper X2 Capacitors PME271M
https://www.hificollective.co.uk/components/evox-rifa-pme271m.html
They are classified as X2 capacitors. X2 capacitors are used in positions where a failure of the capacitor would not expose anybody to danger of electric shock.

Failing RIFA safety capacitors
https://www.youtube.com/watch?v=GDTuHDsHHFA

RIFA AC Filter Capacitor Blowup
https://www.youtube.com/watch?v=njbwdbcfXjc
An attempt to capture the failure of a RIFA AC filter capacitor in a TRS-80 Model II Microcomputer.

Rifa Capacitor Fun
https://www.youtube.com/watch?v=8YhS-k1TRFA
In this video I demonstrate why I ALWAYS replace Rifa capacitors when I am repairing vintage machines.
Do not watch this video if you have a nervous disposition.

RIFA capacitor Blows up! while playing Revox B790
https://www.youtube.com/watch?v=YtGdWZ93-uQ
An old RIFA capacitor blows up while playing a record on Revox B790.

Why Do Rifa Capacitors Fail?
https://hackaday.com/2023/04/01/why-do-rifa-capacitors-fail/

Anyone who works with older electronic equipment will before long learn to spot Rifa capacitors, a distinctive yellow-translucent component often used in mains filters, that is notorious for failures. It’s commonly thought to be due to their absorbing water, but based upon [Jerry Walker]’s long experience, he’s not so sure about that. Thus he’s taken a large stock of the parts and subjected them to tests in order to get to the bottom of the Rifa question once and for all.

Rifa Capacitor Fun Follow Up
https://www.youtube.com/watch?v=TB5FL3vziko

EEVblog #1183 – RIFA Madness (Schaffner Repair)
https://www.youtube.com/watch?v=XAbrU17hLTM&t=548s
Repairing the Schaffner NSD200E Mains Interference Simulator.
And the dangers of bad mains filters capacitors, and RIFA brand in particular.

How ironic! They were advertised as a very safe capacitor type once.

Ohhhhhh this did NOT age well.
A bit like the Rifas themselves.

Now there is even joke:
RIFA = Random Interval Fire Autostarter

Ah Rifa madness. To think some reputable suppliers still have them.

How to fix a device with failed or soon failing RIFA filter capacitor between mains wires:
Replace it with a newer (not Rifa) X2 capacitor of the same capacitance and equal or higher voltage rating.

And it is not only the paper capacitors that fail when they get old…

EEVblog 1486 – What you DIDN’T KNOW About Film Capacitor FAILURES!
https://www.youtube.com/watch?v=ikp5BorIo_M
You might think you know how film capacitors fail and degrade in capacitance over time – self-healing due to surges, right? WRONG!

Metallized Film Capacitor Lifetime Evaluation and Failure Mode Analysis
https://cds.cern.ch/record/2038610/files/45-56-Gallay.pdf

ElectroBoom is fun to watch

https://m.youtube.com/watch?v=TwIvUbOhcKE

So are also those:

Kreosan

https://www.youtube.com/watch?v=3ugxq0FMjoQ

Diode gone wild

https://www.youtube.com/c/diodegonewild/videos

Big clive

https://m.youtube.com/watch?v=RmZGwEPt1ck

Big Clive discovered there’s a “thing” going around where people are charging lithium cells by attaching a stripped USB lead directly to them. Normally lithium cells are very safe if undamaged and correct charging procedures are used. But overcharging them like this can result in cell damage and potentially fire.

Some Lithium cells have built-in protection circuitry and some not. Many of the “found” lithium cells salvaged from disposable devices have no extra protection circuitry because it’s not needed in their application. But when recharging them it is very important to control the charge current and stop charging at around 4.2V

Direct charging with a USB lead has very little current limiting and the charger will often smash more than its rated current into them, potentially damaging the charger too. It will also keep charging them beyond 4.2V and that poses a genuine risk of internal chemistry damage, potentially resulting in avalanche failure where an internal short circuit occurs. If that happens the full energy capacity of the cell will be released extremely quickly resulting in the electrolyte venting as a flammable vapour, and if sparks blow out too it can ignite resulting in a flamethrower effect. The real hazard is their ability to store and release very high amounts of energy. If used correctly and protected from physical damage, lithium cells are very safe.

Selected Viewer comments:

Wow, I appreciate that you took the time to write an in-depth and educational description for this video. I wasn’t aware that you could use the cell’s capacity as a measure for how much current you could push into a cell during charging. These “disposable” batteries are my first experience using lithium-ion cells for projects, so your videos on the matter have been amazing. Thank you for all you do

Basically “Please for the love of god, just use a Battery Management System board.”
Maybe it’s just my previous experience with lithium batteries, but charging a 3.7 (4.2v max) cell directly with a 5v USB connection with absolutely no overcharge/overvoltage protection is a very obvious recipe for disaster to me. I shouldn’t be surprised that there are plenty of horrible ideas circulating on the internet like undetonated land mines waiting for someone who doesn’t know better to come along.

I used to fly a lot of RCs and I had only one experience with a lithium cell venting randomly. I have gone through literally hundreds of them with no problem except for that one. And I’ve always used hobby grade RC chargers for lipo.

Any charge put into a rechargeable battery has to be governed in some way. The current has to be trickled in, not flooded in. Just connecting them up to a, ‘dumb’, USB connector is a very bad idea. As mentioned, it’ll overcharge the battery and cause it to become unstable to the point of bursting/exploding/catching fire.

Most lithium cells I’ve found in multiples devices have a small protection board, however I don’t to know to what extend it protects the cell other than charge current and voltage. If they have over discharge protection that’d be pretty awesome but for now I’ll just stick to the TP4056. Don’t wanna find out the bad way.

One important thing to keep in mind about the board with the TP4506 and the DW01: if you try to use it while charging the cell, the TP4506 will see the charge current as well as the load current and will never reach the charge termination point, potentially overcharging the cell.
So use that board to either charge the cell or protect it during use, but not both at the same time.

That’s very good information, especially since the protected one even have separate B+/- and OUT+/- terminals. From what I can tell fixing this would have “cost” three additional components and a very slightly larger PCB, it’s a bit sad that no one has capitalized on this to provide a better variant (that I can find, it’s all TP4056 with or without protection circuit, no PCBs that appears to be different).
Someone suggested that one could fudge a “load bypass while on USB power” using two schottky diodes (for lower voltage loss) – I may have to test that out next time I use one to confirm that this actually works but the idea looks reasonable (not a guarantee).

Maybe look at other chips from the same series. Some are designed to provide power output without the 10% loss in a schotky diode.

Most people want a pre-existing module so they don’t need to design their own, I doubt anyone charging a lithium cell with straight 5V would be capable of that. Which is why it’s a shame that the common protected TP4056 modules LOOKS like they support “pass-through charging” (separate B+/- and OUT+/-) but doesn’t – and that I couldn’t find any better (commodity, small, simple) pre-made alternatives, whether TP4056 or not.

This spoofing is relatively easy because the actual GPS signal is weak. There are very cheap short distancr GPS jammers. The cheapest equipment required to perform GPS spoofing attacks costs a couple of hundred USD (for example HackRF One and computer), while the software to simulate realistic GPS satellite radio signals is generally widely available. Please note that disturbing GPS signals is illegal in very many countries.

Reas more:
Finnish govt agency warns of unusual aircraft GPS interference
https://www.bleepingcomputer.com/news/technology/finnish-govt-agency-warns-of-unusual-aircraft-gps-interference/

https://www.facebook.com/groups/majordomo/permalink/10162357184499522/