Questions tagged [safety]

*Your* health and safety while working on electrical devices, and designing devices that will not shock, set fire to, or otherwise harm the user of the device.

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36 views

How safe are voltage detector pens and how can I test one's safety?

I'm not an electrician and I have some basic understanding of how voltage testing pens work. I haven't had an incident with them before but I'm still quite concerned about their safety mechanisms. I ...
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1answer
39 views

Wired GFCI vs. 40v 5a battery use near spa

My wife has recently taken to running a cord out near our pool to watch TV. She's very careful, but I was thinking of doing what I can to make it safer, since the outlet in question is NOT a GFCI ...
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1answer
70 views

AC to DC power supply - earth ground capacitance on DC output

I have a mains to 60v DV power supply that I’m using for a project. Needless to say it managed to give me a bit of a shock. This surprised me as it’s supposed to be floating. With no load the power ...
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1answer
60 views

How can I safely test how a power supply handles abnormal situations?

I have a bunch of chinese 5V power supplies. The seller indicates that the power supplies have input protection, output protection, over-voltage protection and short circuit protection. That's all ...
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59 views

Bonding Electric Vehicles: Which System to Implement (safety)?

I am currently working on building an autonomous electrical vehicle and would like some input on which bonding system would be safest and most practical. The system battery is 48V (dc) and which feeds ...
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1answer
109 views

Are paperclips conductive enough for anti-static purposes? [closed]

I have recently discovered that I am a very silly man. Despite this, for the purposes of laptop repair, I still want to ground myself without spending any more money. I have recently come in to the ...
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4answers
118 views

Can I safely ground myself by clipping an anti-static wristband to a half-inserted plug?

I'm having some trouble grounding myself for laptop repair. I cannot get the crocodile clip of my anti-static wristband in to my plug socket (I'm in the UK, so our sockets are a bit difficult) and I ...
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1answer
73 views

IATA battery rules

Following IATA guidelines two threshold limits are indicated: 20Wh for cells and 100Wh for multi-cell batteries. Question: Should I apply 20Wh limit also for cells in multi-cell batteries? Example: ...
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64 views

Is this wiring safe [migrated]

The wall box is from the mid-1950's and my multimeter shows that it is grounded. There are a solid 120 volts when testing between live and ground. I noticed a bare copper wire coming from the cloth ...
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0answers
58 views

Adjustable voltage doubler circuit across resistive load…doable?

Disclaimer: what I am proposing is dangerous, and I know that. I would discourage anyone, regardless of expertise from undertaking such a pointless risk to their health and home. After my recent (mis)...
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35 views

Ground fault interruption in a dryer with ground bonded to neutral? [migrated]

I've posted this issue elsewhere and maybe because it's so boring nobody wants to expend the energy on it (which is fine!) but for me the motivation is 50/50 safety and learning more about electronics ...
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1answer
31 views

ATEX: PCB design for intrinsically safe, output capacitor

We're looking into restricted breathing or encapsulation concept because PCB has a complex circuit that makes it impossible to achieve SMD clearance under 'ic' or increased safety concept. I have a ...
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24 views

IEC 60950-1 Test Report For Power Supply

The current power supply that we have from our vendor has a straight DC connector. That's the way it was tested for 60950-1. If we change the connector to a right-angled DC connector, is the IEC 60950-...
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74 views

Does this circcuit pose a safety risk that could be avoided?

I was looking over the circuit design for OpenEVSE. I was specifically interested in the GFCI portion of the circuit: This circuit measures the current difference between Line and Neutral on a 120/...
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1answer
50 views

Taping down cord with duct tape fire hazard?

Curious as to if taping down a cord is a fire hazard. Some cords have very thick insulation and rubber so I do not see how it would be the case. I will try to find the article and update the post if ...
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1answer
45 views

Why does the high capacitance of a metal oxide varistor affect sensors and signal sensitivity?

I want to know why the high capacitance of metal oxide varistors affects sensors, signal sensitivity. How does capacitance affect sensitivity ? If we add a low capacitor in series will the total ...
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38 views

Can we use tvs and mov together for thruster?

I want to know if we can use both tvs and mov varistor together ? What will be good for thrusters ? And placement between esc and thruster or before esc? Update: system voltage is power supply ...
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17 views

p mosfet calculations reverse polarity for high power ( 48 V , 30 A )

i want to make reverse polarity protection for input 48 voltage , load 30 Ampere 2 dc buck converters. i was searching many solutions like diodes , but i wanna make it with p fet , so i came across ...
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1answer
31 views

Reverse Polarity Protection relay calculation

i want to make reverse polarity protection without voltage drop ,i was searching and i found this https://www.edn.com/design/analog/4368527/Simple-reverse-polarity-protection-circuit-has-no-voltage-...
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10answers
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Is DC 5V and 2A dangerous to me? [duplicate]

I am new to electronics so please forgive me. I am looking at powering a WS2812B RGB strip. Specifically 144 LEDs/ meter. After doing some research I found that 200mA is lethal and can kill. Now, of ...
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1answer
38 views

What 'rated voltage' means in VDE certificates?

In a VDE certificate for a component (plugin green terminal blocks), a column gives the "Rated voltage(s) / V" with a value of "400" without specification wether it's VAC or VDC. Does this mean that ...
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2answers
48 views

BLDC/BLAC controller motor voltage reverse protection

I am currently designing a BLDC controller and keep running into a power safety issue: I have added a smart diode reverse protection controller to my design with its transistor between the fuse and ...
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2answers
35 views

Can I use pre-regulated PoE power safely/within specifications?

I'm attempting to design a PoE PD for fairly high-power applications; chiefly, powering/driving stepper motors. Currently, both motors and drivers run at 24V and will consume about 30W per PD. At that ...
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0answers
47 views

Which implementation of a safety stop is more accurate?

I recently got into an argument with a friend over what the correct implementation of a safety switch for a motor with a spark gap is. So for intents and purposes, here is the simplified schematic ...
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2answers
60 views

IoT Certification Legality

I am developing an IoT product for a company. The product runs off of two alkaline batteries at a max of 3.2V. It is fully enclosed in a solid plastic case, with small panel openings for a switch and ...
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2answers
48 views

How to safely test a Lithium Battery Management System board

I'd like to design a Battery Managements System board (based on TI bq40z50-R2) for my own small (2-4s) lithium battery pack, but I am still unsure how can I test it safely. I am worried that an error ...
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0answers
18 views

Using a TP4056 with a 08570 Battery

Will a TP4056 (the ones with mini USB and no battery protection) charge a 08570 battery safely? From what I can tell the battery does have built in battery protection but I cannot find much ...
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1answer
28 views

Designing an over discharge lithium ion protection circuit

I am trying to build a portable RGB LED display that runs off a Lithium Ion battery. After a few days of research, I understand the importance of using a dedicated IC to handle charging the battery, ...
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2answers
110 views

Ws2812b circuit safety with 5V 12A

i am making a arduino project using 5v ws2812b 300leds/meter. Its going to be a motion activated led strip that runs along the side of the stairs. I will be using 3.5m of the led strip so 210leds at ...
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1answer
33 views

Current flow in trailing edge dimmer

I was trying to learn something about dimmers for light bulbs. After some reading, I found that most trailing edge dimmers contain some variant of this: Found for example in this diy-project or this ...
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2answers
655 views

How safe is using non-RoHS parts?

I was wondering the safety of using non-RoHS parts for hobby projects. I already use non-leaded solder, but some of the parts I have are not RoHS compliant. How much would I, and my family, be exposed ...
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1answer
50 views

Safety Rated Sensors [closed]

I am trying to find a safety sensor for a machine. The sensor should be safety rated as it will be used to detect if a cover is removed and will shut down robotics and uvc bulbs which is harmful to ...
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2answers
71 views

Abusing EPS connector to power LED's?

I'm working on the wiring harness for a PC build that's going to include a bunch of (5050) LED strip lights. The strips will be wired to fan connectors (more details at end). For testing, I've been ...
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2answers
134 views

Back branches in code

While reading this file on software hazards this slide says: "No Back Branch in the Code" I wonder what does it mean? Normally when we write code in C-language then we don't actually do branching ...
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1answer
35 views

Protection circuitry for AC/DC converter

I'm using the RAC02-GB (Datasheet) as an AC/DC converter and I'm confused about the protection circuit they included in the datasheet: I want to make sure the AC/DC converter has the proper external ...
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1answer
63 views

Oscilloscope and Electrical Safety

I was reading an article in a magazine in which the following sentence is written about a circuit that generates a certain waveform on a load R (in which one of its terminals is connected to the earth ...
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4answers
143 views

Safety: Can I harm myself using an AC, 9V 500mA power supply for experiments?

I'm about to embark on my first electronics project and would like to check off a safety question: I want to build a bicycle hub dynamo -> USB charger based on these instructions. It is basically a ...
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2answers
104 views

Can an electrified wire ever be safe against bare skin?

This could sound ridiculous to someone with an ounce of experience, but I'm just getting started, so here we go ;) Full question is 3 parts... First, what is the lowest amperage needed to light an ...
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1answer
118 views

Safety precautions when developing and testing mains voltage devices [closed]

Specifically, I am planning to design and build an energy meter to measure power drawn from mains - 120V 60Hz. What are the risks associated with developing and testing this device and how to minimize/...
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2answers
103 views

Running an electric motor beyond its ratings

I ordered a 36V 500W brushed DC motor but unfortunately a 24V one came. I'm faced with the dilemma of returning it and waiting for a month before getting a refund, then ordering a new one and waiting ...
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1answer
685 views

How safety capacitor replaces optocoupler

I see some phone chargers using safety capacitor (after some research I found its safety capacitor)But not optocoupler to isolate in and out . How safety capacitors replace the optocoupler
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2answers
123 views

How does electrocution (fatal) happen? [closed]

I'm trying to make my workshop safer but I can't understand how electrocution happens. For example, one hand is touching to live wire and neutral wire is not touched. If I know right, current flows ...
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2answers
99 views

Is this the correct way to wire my transformer?

I am building a 12 V dual power supply. Since this is the first time I will be using mains (230 V). I would like to make sure that I am not going to burn down my house. The transformer I want to use ...
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3answers
78 views

Safety and isolation transformers

What safety measures can be taken when using a 1:1 isolation transformer in order to avoid electric shock even if someone touches both ends of the secondary? Would an insulation monitoring device be ...
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5answers
189 views

How are electric water heating elements isolated?

From what I've seen and understood, electric water heating elements are usually copper tubes/pipes with electricity running through them to heat up the surrounding water. I'm not sure if the ...
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1answer
25 views

What safety regulations do I need to follow for wiring of a decorative lamp utilizing a fluorescent tube with g10q fitting?

I'm building a cast concrete decorative lamp. It will use an exposed circular fluorescent bulb, which attaches to a g10q lampholder. I understand I will need to wire it up to a ballast and starter, ...
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1answer
48 views

AC power supply safety

I am planning on building a vintage tube radio from schematics. Part of the radio will include its (multi-voltage output) power supply, with an AC power cord, AC switch, and transformers. Are they ...
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1answer
111 views

Placement of varistor with respect to fuse

My design includes a pretty standard AC/DC converter powered by mains for intended use at home. For overvoltage and overcurrent protection, I am planning to use a combination of varistor and fuse ...
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1answer
109 views

Are there more (mains) electrical safety incidents in the United States compared to the UK? [closed]

Forgive me if this question isn't exactly "on topic" for this site -- it's a bit meta. I am an academic in the UK, and I occasionally design electrical devices that plug into "the mains" in one ...
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1answer
56 views

How to measure laser class of LIDAR

I just bought a LIDAR with the intention of building an indoors robot that uses it to navigate rooms in my apartment. The manufacturer website states: Low power infrared transmitter conforms to ...