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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.

-4
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0answers
90 views

Lead Contamination in house after touching solder [duplicate]

I may have accidentally touched my laptop and keyboard and mouse and maybe my desk after soldering the one time I did and was wondering if it's contaminated with lead and how to clean/dispose of it if ...
19
votes
11answers
4k 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 ...
2
votes
3answers
172 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 ...
1
vote
0answers
26 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 ...
0
votes
0answers
90 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 ...
0
votes
1answer
24 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 ...
0
votes
2answers
155 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 ...
0
votes
2answers
56 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 ...
2
votes
2answers
80 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,...
0
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2answers
60 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 ...
5
votes
1answer
82 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 ...
3
votes
0answers
37 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). ...
51
votes
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 ...
1
vote
3answers
28 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 ...
0
votes
1answer
34 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 ...
1
vote
3answers
66 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 ...
2
votes
2answers
72 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 ...
0
votes
1answer
57 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 ...
1
vote
3answers
147 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 ...
4
votes
3answers
88 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 ...
0
votes
2answers
139 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 ...
0
votes
1answer
52 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 ...
0
votes
1answer
27 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 ...
7
votes
4answers
3k 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 ...
1
vote
1answer
114 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 ...
0
votes
1answer
30 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 ...
1
vote
2answers
29 views

Product Safety Testing - EU

I was recently hit with the thought as to what safety tests a domestic electronic product has to go through before it is sold to consumers more specifically in the EU? I have been looking through ...
6
votes
2answers
578 views

Safely burning resistors - carbon film vs. metal film

Short: Are carbon film resistors and metal film resistors equally safe to burn? Long: I want to explain to children that they need to carefully calculate and check resistor values. I don't only ...
0
votes
1answer
104 views

What precautions should I take to setup a home electronics lab? (Living in the UK) [closed]

I'm soon to be buying a house in the UK and would like to setup an electronics lab in the garage (attached to the house).The type of equipment I'll be using is nothing out of the ordinary: ...
11
votes
3answers
3k views

Making a device explosion proof

I am working on prototyping a gas leak detector device to be used in homes, it should have two small windows in the casing to allow sound to go out and the other window allows gas to reach the sensor. ...
4
votes
1answer
68 views

Is isolation between user accessible circuits and protective earth necessary for safety?

First let me say that I understand that this question is best answered by someone familiar with relevant standards (whatever those may be). Let me give some background. When I'm designing a board at ...
0
votes
1answer
96 views

Why not keep distribution transformers secondaries floating? Why do we need to earth them?

We use isolation transformers for many reasons, one of them is may be safety. So why not just keep the distribution transformers floating? If they're floating, then someone touches the live wire, I ...
3
votes
1answer
123 views

Why is touching the live wire of a socket dangerous inside an apartment few stories up?

Let's say I touched the live wire of a power socket in my apartment that is located at the fourth floor of an apartment building. The current needs to flow through my body to ground in order for me to ...
4
votes
3answers
111 views

Protecting against a SSR failing closed

In a project I'd like to control a heating circuit with an SSR, and I'd need a contingency plan for when the SSR fails closed, and the microcontroller cannot turn off the heating element, which would ...
0
votes
1answer
30 views

Fusing on dual voltage industrial device

Please forgive me if this question has been asked before. I am designing a heating device that will be sold to industrial consumers. In our past designs we have had multiple versions of the same ...
0
votes
1answer
22 views

Can a power surge have a different effect on a led driver when floating?

I have a LED driver which has 3 connections on the AC side , L,N and ground. In the event of power surge, can there be a difference in effect if the GND connection of the LED driver is floating or ...
0
votes
0answers
100 views

How to line a Metal Melter secondary for higher safety

A Metal Melter is a kind of home-made low voltage (less than 40 volts, mine is 3v) welder (small-scale) made from a microwave oven transformer (MOT). I left the primary intact (the thicker wire, which ...
0
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0answers
39 views

Electrical safety measures in LED bulbs for the European market

Which electric safety measures are required to introduce LED bulbs on the European market? Which electric measures prevent that the plastic LED bulbs will melt down or ignite at the end of life? I ...
4
votes
1answer
68 views

What are the tradition ways to signify/advertise that a potentially dangerous long-running test is in progress? [closed]

I frequently need to run long-term tests which have some potential for damage or harm if e.g. someone disturbs the test apparatus without being aware that it's running a test. Say for example ...
0
votes
1answer
377 views

Measured continuity between live and neutral

I was trying to get rid of the humming noise coming from my speakers in my hi-fi system. It is an old piece of equipment from back when the UK appliances did not come with the mains plug and you had ...
0
votes
1answer
64 views

Is this soldering iron and power supply combo grounded and if so, how?

I'm interested in a TS100 soldering iron as a decent starter iron and a light one that doesn't take up too much space. It doesn't come with a power supply though, presumably to keep it flexible as it ...
1
vote
1answer
47 views

LED current source circuit design concerns

TL;DR: Read the bulleted list below. I am designing a simple constant current source to power up some LEDs inside arcade buttons. My project consists of 20 of these buttons. Every button is ...
0
votes
2answers
126 views

Power tool safety: Grounding v/s Double insulation

OSHA regulation 29 CFR 1926.404(f)(7)(iv) states that electric power tools must be grounded except when they are double insulated. I quote from the Black & Decker rotary drill manual: "Do not use ...
0
votes
2answers
164 views

Amperage rating of thermal fuse

Consider this SW-104T thermal fuse. It has a current rating of 10A. Does this mean that in addition to its thermal fuse capabilities (blowing at a certain temperature profile), it also behaves as a ...
0
votes
0answers
15 views

Substitutability of thermal fuse

I have had this SW-104T thermal fuse blow on me. I'm not in a situation where I can obtain an the exact replacement, so I am wondering about the substitutability of thermal fuses. If I match the ...
0
votes
1answer
422 views

Is it safe to use my multimeter to test UK wall outlet voltage?

From the question it should be clear I'm no expert. Just want to learn. I have a digital multimeter. If I connect the multimeter to hot+ground & hot+neutral on the 240v 50hz (max ~30A) AC wall ...
1
vote
2answers
94 views

Why do we have “live” and “neutral” wires? [duplicate]

Our house wiring is AC. I thought that AC means we have current flowing from Wire 1 to Wire 2, after 1s/Frequency it flips and current flows from wire 2 to wire 1 and this goes on and on. I heard ...
0
votes
3answers
94 views

Do 240V AC switches only need to open the active wire?

I want to add a simple inline switch to a small, mains powered lamp (~240V AC, 10W Max). It's earthed; it has a typical 3-core cable with a 3-pin plug. I bought a bunch of switches, expecting ...
1
vote
1answer
54 views

Safety Rule: Sum of wire lengths over two phases may not exceed X. What is this for?

Everybody knows various flavors of the rule "don't connect too long electrical lines to an outlet / generator / whatever". They sometimes come in the form of "don't chain your extension cords". As far ...
0
votes
1answer
139 views

Is it safe to measure 220Vrms@50Hz on DSO directly?

I borrowed my friend's DSO to complete my project(Hantek DSO5072), but on scope it says CAT II/400V. So is it safe to measure 220Vrms@50Hz with it?