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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1k views

Safety precautions when making a commercial electronic product

I have designed and fabricated an electronic device. High level explanation for this device is as follows: The device designed scans the environment for RFID tags and when a tag gets too close to the ...
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1answer
76 views

Safe to turn off power by removing a plug fuse indefinitely?

I'm trying to turn off the power for my dining room light and as I live in an old apartment, my fuse box only has plug fuses (and a main fuse you pull out). My plan is to cap the AC wires in the ...
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0answers
22 views

One double pole relay or two single pole relays for live and neutral?

I'm designing a PCB that will control AC 240V electric tools. For now I decided to use a single double pole relay to switch live and neutral lines. Is it also safe to use two separate single pole ...
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0answers
142 views

Will my 555 timer circuit work the way I want it to?

Essentially, I am trying to implement a safety system for another project of mine. I am running a very high current through a rather large solenoid and want to ensure that a failure in its control ...
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0answers
41 views

Right way to couple DGND to Chassis ground

So we all know certain things: DGND (and subsequently AGND) needs to be coupled to Chassis ground, or Earth at one position, at least, in a device. The Earth is otherwise considered as a hazardous ...
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5answers
2k views

How to safely power a large LED strip project

I'm making an LED matrix with a board and 4X WS2811 strips (5 m length, 150 LEDs). Each strip is 45 W, takes 12 V and is 3.75 A. I have connected them in series and injected a 12 V, 60 W/5 A adapter ...
2
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0answers
19 views

Standards Compliant High DC Load Safety Interlock System

I have a single AC-DC supply (42V @ 600W) which supplies three motive loads. Each motive load is physically separate and has its own cover which prevents the operator from gaining access to the moving ...
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1answer
23 views

Identifying Neutral/Active when wiring a caged SMPS

Just received a switch mode power supply from china and wanted to double check everything before applying power - The screw terminals coming from the cage have Live, Neutral, Ground marked with a ...
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1answer
73 views

High Voltage Safety Questions

I'm working on a project that uses 1700VDC provided from a 220V:1200V isolated toroidal transformer, bridge rectifier and filter cap. I have no experience with high voltages, so I'd like to ask you ...
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1answer
71 views

Handcuffs as protection?

I am not familiar with electronics at all, but as I was strolling through the stack exchange network I've noticed how it is dangerous to electrocute oneself by touching a wire with one hand and ...
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1answer
500 views

What is this electrical symbol? T with overbar in down-pointing triangle

I'd like to use an old laptop AC adapter in conjunction with an adjustable buck module as a project power supply. It works, but I'm ignorant of some safety details; for example I'm uncertain whether ...
3
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2answers
231 views

ESD protection during lightning storms

I'm new to electronics, and I'm currently building my electronics area. Let's say that I have an ESD bench mount drilled into my wooden workbench, and this ESD bench mount is then connected to the &...
3
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1answer
86 views

Are IR LEDs placed under the same category as lasers?

I am creating a device which uses IR LEDs to illuminate the human eye, while an IR camera records the pupil dilation. From my research, I see that there are two standards which are related to the ...
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1answer
57 views

Replacement of a safety capacitor

I would like to know if I can replace a safety Y2 capacitor (222m 300V - which is a 2.2nf-)with a safety X2 capacitor temporarily. I'm in a hurry and I already ordered the replacement part but while I'...
3
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1answer
83 views

PCB Mounting solutions in outdoor enclosure?

I've completed the design for my pool timer and now I'm down to designing how this board will actually hold itself inside an enclosure. I already have a box that I'd like to re-use. It looks like ...
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3answers
125 views

How to connect 5 kW electric heater to the weak wiring in house?

The water heater has a 5kW heater and requires 20A. Unfortunately, the wiring in our house is old and this allows us to get only 10A. Is there an easy way to reduce energy/current consumption and ...
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0answers
51 views

Heel strap vs wrist strap around ankle

I am a novice to electronics, and I am currently building a home workstation. In this question on ESD chairs, the user Sparky256 said the following in his answer: If you are wearing BOTH a wrist and ...
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2answers
259 views

ESD chair for home workstation [closed]

As mentioned here, I am a novice to electronics, and I am currently building a wooden workbench. The workbench will have an ESD bench mount and ESD matting over the entire bench. Furthermore, the ...
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2answers
70 views

How does equipment ground protects us from electrical shock?

What I have always learned is current leave the source and return back to the source, forming a closed circuit, here are the two thought experiments I had and got confused: Scenario 1: Here I have a ...
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2answers
79 views

ESD safety when working across multiple workbenches/tables

I am a novice to electronics, and I am currently building a wooden workbench. The workbench will have an ESD bench mount and ESD matting over the entire bench. I now want to have a small fold-out ...
3
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1answer
98 views

Is there a safe way to operate any type of a tesla coil on a functioning modern car (moving road vehicle)?

(Updated with clarifications) Could a tesla coil be safely built, installed and operated on an active road vehicle which is driving a regular city street? Let's say we want the discharges to be 20-...
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0answers
42 views

How safe are Isolation Amplifiers compared to Voltage Transformer

I was searching for a miniature transformer for my 240V AC voltage measurement circuit and a kind individual recommended me a pecular IC. The IC is a Differential Isolated Amplifier AMC1100. And it ...
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1answer
42 views

How much clearance do I need between floating ground and earth referenced ground?

I have two circuits where one side is earth reference and another floating. The floating circuit is isolated by a transformer and talk to the earth reference circuit via opto-coupler. During final ...
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1answer
54 views

Maximum amps over 24 AWG CAT5 wires [duplicate]

I have a project that runs on 5V and should draw a maximum of around 500 mA. There is an existing CAT5 cable running conveniently to this project. I'm considering powering the project by using two of ...
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1answer
48 views

Connect the oscilloscope to equipment with a common neutral and ground

I watched a video. At 3 minutes, the situation is shown when neutral and ground are joining. Why can this be dangerous? If we are talking about an oscilloscope, the crocodile must already be connected ...
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1answer
73 views

Checking if a device is safe to use

For someone with no knowledge in electrical engineering, is there a way to check if a device is "grounded" (?) and safe to use? It is not uncommon when shopping for appliances online (eg. lamps), ...
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4answers
230 views

Undervoltage protection strategy for Li-ion batteries

We are using a Li-ion battery with built-in safety PCM (Enix MGL9070), a gas gauge to monitor the battery voltage (STC3115A from ST) and a battery charger (bq24133 from TI). To protect the battery, ...
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1answer
45 views

Electric shock from cover of preamplifier

I'm using a Focusrite Scarlett as a preamplifier between my computer and amplifier. The preamp gets power only through a USB connection. Sometimes when I touch the cover of the preamp, I can hear a ...
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2answers
62 views

Feedback regarding isolation practices on a 5V/Mains PCB

I am currently designing a PCB for a project including PID-control of a heater. The heater runs on mains (220V) and is controlled using zero-crossing switching to regulate the power and minimize EMI ...
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1answer
48 views

Temperature of Power Driver ICs

I'm using TI DRV595 power driver in an application requiring several amperes of current. My observation using thermal camera has been that at 3.5 A the driver IC core reaches temperatures around 90 ...
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2answers
66 views

Overvoltage + Overcurrent protection

Our compliance agency believes that it is all too likely that a 50 V power adapter is used instead of our 5 V power adapter. Regulation wants a fuse which can protect from 50+ V, and not allow 15 W ...
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3answers
101 views

How much 12V DC current can I safely draw from an AC 230V 13A socket and why?

In my cabin I have a sollar cell and a 12V battery that I use to power my electronics. However I'm dissatisfied with the standard CL sockets used in cars (apparently I'm not the only one) and I ...
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0answers
24 views

Lithium Ion Battery - Testing & Self Discharge

It is suggested and commonly understood that if Li-ion batteries drop below a certain threshold that we consider the cell(s) unstable and untrustworthy with a loss in cell capacity and that increased ...
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3answers
105 views

What's the difference between these plugs?

I'm not an electrical engineer, but I play one on TV. Can you help me be more realistic? Our facility has three items that run on three phase 208 and plug in at a temporary building using CS (...
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1answer
48 views

UL certification and laser tag equipment

We are a 32+-year-old laser tag equipment company. We purchase parts overseas and assemble them in the US and have hundreds of installations all over the world. We have been told by 1 location that ...
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1answer
36 views

Deep cycle battery charging ventilation [closed]

I have a small boat and the main deep cycle battery is located just under a "shelf" like thing near the transom that acts as a cover for the gas tank and battery. On one side, it is completely open (...
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0answers
64 views

How can I protect my amplifier, MCU, and laptop from damage in my application circuit?

I am trying to integrate a few devices for a laser stabilization system. I have a tentative circuit diagram that I'm asking for more expert guidance in implementing. I am using an MX200 from ...
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0answers
20 views

How do I select the subclasses of X and Y safety capacitors? [duplicate]

While designing a switch-mode power supply, I've been reading a lot about X and Y rated safety capacitor. Although I fully understand their use and limitations, how do I determine if I need a X1 or X2 ...
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1answer
29 views

Running digital ground at AC line potential (not neutral)

I've run across an interesting WiFi dimmer module known as a Shelly dimmer. This bright green module is designed to be used inside an electrical box. Most of it's user interface is over line-...
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1answer
88 views

Repairing burned PCB traces for 220V. Is it safe if I don't know why they burned?

I'm trying to fix the cooker hood of my kitchen and I found that the problem is in the controller. The PCB has two burned traces, respectively to the electric source of 220V (neutral and phase... ...
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0answers
36 views

Heatsink Crossing Primary and Secondary Sides in Switched-Mode Power Supply

I've taken apart a non-oem laptop power supply. There is clearance on the board between primary and secondary. However, they've placed a single heatsink across the board for the primary and secondary ...
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4answers
208 views

Adding to the output of a DC/DC Boost Converter using the same power supply as the input?

I've got a project that requires a variable output between 24-48V. This needs to be continuous-current, not PWM. Items that I have handy from my 'box of bits', and ready to work with are: an 0.6-36V ...
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2answers
58 views

Can galvanic isolation be performed at the user interface (UI)?

With capacitive touch sensing and transparent materials, it seems like it would be possible to run small digital devices from A/C mains without a transformer isolated supply. Is there a flaw in ...
3
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2answers
222 views

In 2020, what are the most common approaches to power-line-communications for hobbyists? (updated)

I'm looking for modern control protocols, designs and/or components to simplify controlling (and running) a very low power system on a chip safely from mains power. I'm in the USA, and on a hobby ...
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2answers
48 views

Should I be worried about a surge protector near my pillow

I have just realized how close my surge protector appears to be to my pillow. It is about 20-30cm away. Should I be worried about any EMF/radiation/something else? The surge protector itself is new ...
2
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2answers
68 views

A safety relay systems circuit

Can someone help explain the operation of a safety relay system. I know that they can be connected to e-stops for emergency stops but I don't understand the relays and how they operate.
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0answers
50 views

Concentrated Ozone Treatments for COVID-19 Sterilization: What levels and duration are safe for consumer electronics?

Operating a critical IT service for necessary businesses brings some risks at this time that need to be mitigated. I have some powerful ozone equipment used to sanitize / sterilize rental property and ...
6
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3answers
177 views

What happens to parts of induction cooker magnetic field not covered with the pan?

An induction cooker works like this. There's a flat coil of wire under the cooker surface which is connected to a source of high frequency AC and it produces an oscillating magnetic field with field ...
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1answer
61 views

How safe is to work on an ATX PSU as a bench power supply?

I'm trying to convert an old ATX PSU into a workbench supply. I saw there are many safety warnings about discharging the internal capacitors before opening the PSU. I'm not really concerned with it as ...
2
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1answer
76 views

Is it OK to have a connection between 0 and PE on a DC device?

I have a device meant to be used inside electrical cabinets. It has a metal casing and is powered by 24V DC. It has three power connectors: 24V, 0V and PE. I was surprised to find out that 0V and PE ...

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