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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23 views

Can I use a two wires BMS to charge a battery without the Balance wires connected?

I bought a new 10s BMS (with Bluetooth) to replace a damaged one of my ebike battery but I did not understood that the Balance Cable was different. Also the new BMS only have 2 thick wires. B- and C- (...
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19 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
45 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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22 views

Temperature Sensitive FET to Block Charging Current to Secondary Battery?

I am working on a design that needs to meet EN 62368, and we are using a Texas Instruments battery protection IC as the primary means to protect our lithium ion battery from overcharging. Our safety ...
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1answer
31 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
107 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
54 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 ...
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1answer
75 views

How to power up a project with 3 devices, between 0 and 12 volts

I'm working on a project which involves a DC heating element, a computer fan and an Arduino/ESP8266. I'd like to use one power supply for those devices..... The requirements: The heater needs a ...
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3answers
65 views

Electrical Standards - Earth Wire at Low Voltages?

I got a question about safety standards: I'm designing a consumer device and I'm not sure whether I need an earth wire. I have an AC-DC converter plug that outputs 5 V and up-to a maximum of 1 A ...
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1answer
35 views

Normally Closed Negative Output, Positive Input Relay

I'm attempting to wire up my remote start in my manual transmission vehicle to ONLY start when the vehicle is in neutral. The way that the transmission works is like this: When in neutral, resistance ...
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0answers
83 views

How to know what is the safety standard to apply to a PCB design?

I want to design a PCB with some points at some KV during certain times, less than 10KV and no more than 30mA of current. After dealing with concepts and getting the main idea about my circuit needs, ...
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3answers
63 views

What connectors should I use with 5V DC current?

In a personal project, I need to power several 5V appliances which, together, use up to 12A. I want to use a 60 inch cable between a case to which those appliances are connected, and the transformer ...
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2answers
54 views

Earth continuity of slot together aluminium enclosure

If I were to use a slot together aluminum enclosure for a mains powered device, and I earthed one panel of the enclosure by fitting a stud, how could I ensure continuity of the earth to the whole ...
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38 views

Does the Machinery Directive (EN60204) require separate mechanical Start and Stop switches?

I have a prototype machine with mechanical moving parts (all contained inside a transparent interlocked enclosure) to review. Single-phase AC power enters at the rear via a fused IEC 60320 C14 inlet, ...
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36 views

Calculate electric field from wire with AC current through

Here an experiment picture The wire(with some resistance) connected to 220 V 60 Hz AC voltage source. The peak current through wire is 0,3 A How to calculate mean, or at least peak electric field ...
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3answers
101 views

Testing and safety requirements for selling homemade electricals

I am currently researching and designing electrical audio equipment, example devices: Tube and solid state guitar amplifiers Guitar effects pedals Mixing / filtering units Synthesizers Some of these ...
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2answers
133 views

Can a stripped USB charging cable electrify you and how dangerous would it be? [closed]

I have a USB type C charging cable that I charge my cellphone with. Couple of days ago I found out that it got frayed on some parts of its plastic cover. I always charge my cellphone in bed and before ...
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1answer
53 views

Fuel Level Sensor Safety

I'm looking up fuel level sensor manufacturers (Omnicomm, Technoton etc) and noticed that a lot of them offer capacitive fuel sensors for all types of fuel. However, based on my understanding, ...
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2answers
93 views

Is there a risk of 18650 li-ion battery explosion in a low current application?

I have several used 18650 batteries from my old laptop battery. They all look OK, I have charged them and discharged. The capacity is around 1700 mAh, nominal capacity was 2500 mAh when new. I'm ...
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2answers
99 views

How damaging can a leaky microwave oven be?

This question is mainly about EMC and disruptive RF emissions. I have noticed recently that each time we use our microwave oven the WiFi network becomes unusably slow (it is still working if you get ...
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3answers
57 views

Can a desolder pump aerosolize lead particulates?

I have been reading up on the dangers of leaded solder. I understand the risk of actually soldering with it are minimal but my question is specifically its removal via "solder suckers." Does this ...
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0answers
28 views

Electrical Safety Guideline for LVD Compliance

We are making a product -a warning light- with 220V rated voltage. The product has a non isolated offline buck regulator. The 220V part can be accessed without the use of a special tool (there is a "...
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3answers
4k views

Is this resistor leaking? If so, is it a concern?

I found this resistor on the control board of an old Whirpool washing machine: Is that fluid leaking from the resistor? (Why would that happen?) Could it be something like stray epoxy or a chemical ...
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1answer
81 views

EL Wire safety? [closed]

Electroluminscent wire is often used on party-shirts or to decorate other wearables. They come with little "EL Inverters" that run on 3-12V DC power. I measured the output voltage that's output into ...
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2answers
50 views

Connect charger to device first or to power first? [closed]

What reduces the chances of frying a device? Connecting the charger to the power plug first or to the device first?
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11answers
5k views

How to safely discharge oneself

At work I have the problem that I seem to collect a lot of static charge as soon as I leave my desk and return. I am not quite sure why this happens. Strangely enough the effect is stronger the ...
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3answers
228 views

Lead Contamination when Soldering [duplicate]

I bought a soldering station a while back and was practicing on a kit and had the website on assembly up while I was soldering using 60/40 tin-lead solder. Should I worry about splatter on the ...
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28 views

Standard LiPo battery packs & product liability

I'm designing a high-power portable product that I would like to eventually bring to market. I need to use LiPo battery packs in order to achieve sufficient energy density, but I do not think I will ...
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0answers
129 views

Safe Voltage/Amperage for Soldered Wires - aka When to Crimp Instead

I have found a lot of information that circles around what I'm looking for, but nothing that directly answers it. It is possible there is no right answer.     I am jealous of the Macbook ...
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1answer
42 views

Clearance distance and resin filler

I'm designing a circuit to detect presence of AC line voltage. It's actually a very simple device with AC side made up of a 200Kohm 1W resistor and an optocoupler and a protection diode. There will be ...
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2answers
169 views

Microwave starts working when door opens - how dangerous is it?

I've just rented a house that came with an equipped kitchen, and I've found that the microwave has a rather weird behavior - opening the doors seems to trigger it to start working, which the owners ...
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2answers
60 views

Earth line safety [closed]

I am working with a conductive appliance that a user will be in constant contact with over extended periods of time and the appliance is constantly earthed. These two facts cannot change, other than ...
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2answers
90 views

Why is 100 volts or less generally “low voltage” and “safe”? [closed]

In the United States in many state jurisdictions, wiring that operates either exactly at or below 100 volts is not required to be installed by a licensed electrician, and no site plan, building permit,...
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2answers
75 views

Optocoupler isolation necessary?

The circuit diagram below shows two possible options for a circuit: simulate this circuit – Schematic created using CircuitLab The difference between both circuits is the use of the ...
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1answer
97 views

48VDC safety precautions?

I am building a bit of equipment that requires 48DVC @ 2.5A to be brought out of the metal box housing it. I intend to feed it through a piece of plastic tubing along with a sensor wire, which exits ...
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0answers
41 views

How to wire an entire room / kitchen with LED light strips? [closed]

As the question suggests, I'm looking into adding LED light strips throughout the kitchen (over cabinet, under cabinet, and kick -- I think under the countertop would be neat, but harder to hide). ...
52
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7answers
10k views

Does a dangling wire really electrocute me if I'm standing in water?

We've all seen this scenario in movies; somebody has to cross a room half filled with water and there is a dangling electric wire that shoots sparks everywhere. The poor person has to cross the room ...
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3answers
32 views

Connecting the Block AIM 5.0/2.0 auto-transformer to UK three-wire plug

I am not electrically very knowledgeable person. At the moment I am trying to connect a Block AIM 5.0/2.5 Auto-transformer to a piece of very sensitive medical equipment. The auto-transformer was ...
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1answer
36 views

Optimal Grounding for a PVC Dust Collection System?

It is common in woodworking (A hobby of mine) to make a dust collection system (Basically a tube hooked up to a vacuum to carry away dust created from automatic woodworking tools) out of PVC. We'll ...
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3answers
95 views

Maximum safe amperage for LED Strips

A lot of online resources never question the use of high amperage power supplies for powering LED Strips. As an example, 5 meters of low density (30 LEDs per m) WS2812B strips already use ...
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2answers
73 views

What's a safe method for determining the switching frequency of a blackbox ACDC converter?

My project uses an off-the-shelf ACDC converter that conceals design details from such as switching frequency (or SF range). It's 24 V output rated to 5 Amps. I want to measure it's switching ...
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1answer
59 views

Voltage on the grounded conductive devices when plugging in non-grounded outlet [duplicate]

Most outlets in my house are non-grounded (line and neutral contacts only). I just bought a Hakko fx-888d soldering station, and immediately noticed that touching the iron-station cable gives the same ...
2
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3answers
230 views

12v nichrome wire water heater. Is it safe?

I want to heat the contents (water) of a two liter thermos flask using a low power (50-100 watt) 12 volt DC heater. Rather than buying a tiny little immersion heater, I've got some nichrome wire ...
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3answers
90 views

If two objects are grounded, why do they still need to be bonded? And if they are bonded, why does each still need to be grounded? (fire safety)

When transferring a flammable liquid, both the container and the receptacle are supposed to be grounded and bonded. If they are both grounded, shouldn't the change on each be equal to ground? And if ...
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2answers
217 views

Reliability of STM HAL driver For Safety Critical Application

I'm working on a project which must be used in an automotive application and act as a node into the multiplex CAN-BUS network. There are number of I/O that must be actuated and some of them had a ...
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1answer
54 views

Wiring a traffic light

So I have aquired 1 light of a traffic light that I salvaged from a local dump. I want to try and connect the light to use it like a lamp, however I am a little worried by it as the connector only has ...
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1answer
36 views

Definition of Field Wiring Terminals as in UL 499

I'm wondering if anyone can tell me where I can find the definition for "field wiring terminals" as referenced in UL 499 "Standard for Safety Electric Heating Appliances" table 27.1 "Minimum ...
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4answers
5k views

Is it Safe to Plug an Extension Cord Into a Power Strip? [closed]

Just a bit of context, I am a technology enthusiast. I love everything from software to hardware, Windows to Linux, Computer to Phone, and everything in between. So, I wouldn't be surprised is my ...
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1answer
317 views

Proper Chassis Grounding

I'm starting to design things that run off mains voltage and I want to be sure that I have a proper connection from my chassis to earth ground. I've been reading a bit about proper grounding and have ...
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1answer
40 views

Can I simply add a 240V Neutral to SONOFF TH10 when replacing wall thermostat

So, I have purchased a SONOFF TH10 wanting to use it to replace my wall mounted thermostat. The thermostat has 2 connections: Always-Live and Switched-Live (which is activated of course by the ...