Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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.

3
votes
0answers
32 views

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

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). ...
0
votes
0answers
6 views

Proof butt connectors are up to code [migrated]

I'm about to add butt connectors to the plan for wiring my power circuit. How can I prove, with documentation, that these are safe and up to code? My location is Ontario, Canada. My application is ...
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
2answers
43 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
71 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
56 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
126 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
116 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
51 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
24 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
78 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
28 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
547 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
63 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
119 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 ...
3
votes
3answers
95 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
19 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
99 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
votes
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
278 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
57 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
46 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
99 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
136 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
302 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
79 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
89 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
133 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?
1
vote
0answers
56 views

Is this safe? Wiring for power relay jqc-3fc(t73)dc5v

I have an ac relay jqc-3fc(t73)dc5v that I am trying to use with a atmega and drive with 5v. Is the wiring as shown in the picture a good idea? Considering that ac and DC need to be very close ...
0
votes
1answer
108 views

Can a magnet cause a microwave oven to unsafely radiate energy?

I've already successfully warped the colors on a large old CRT Television by setting unshielded speakers on top of it. If I understand correctly, this was due to the deviation of the electro-magnetic (...
0
votes
1answer
95 views

How much current does it take to injure me? [duplicate]

I'm building a 5 V and 4 A circuit that will be in contact with the body. How can I know if this amperage, in case something goes wrong, will not be a problem for my health or my life?
0
votes
1answer
125 views

Using a residual current device when there is an isolation transformer

In a system, currently there is no circuit breaker and RCD, but there is an isolation transformer as in the diagram below: simulate this circuit – Schematic created using CircuitLab As you see ...
1
vote
0answers
44 views

Why are contactor coils connected to two different safety relay outputs?

When looking through a manual for a safety relay, I began to wonder why the coils of the load contactors (K3 and K4 on pages 14-15) are always connected to two different NO contacts of the safety ...
0
votes
3answers
271 views

Can 10-100mA kill a person / be deadly? [duplicate]

According to various sources something as little as 0.01A = 10mA can be painful, at 0.1A = 100mA you can expierence * "ventricular fibrillation of the heart". "an uncoordinated twitching of the walls ...
0
votes
2answers
83 views

Use of relay in a gas sensor (safety issue)

I have developed an MQ-5 based LPG gas sensor which uses a relay. Is the relay itself a fire hazard (while switching) if gas is in the vicinity ? Thanks.
-2
votes
1answer
88 views

How (not) to set the house on fire? [closed]

With a recently renewed spark of interest in electronics, I’m now starting to solder stuff and build more permanent devices than before with breadboards. But with great power comes great ...
0
votes
1answer
33 views

Can you bridge off of a 240 V Breaker Box that connects to an Intermatic Timer?

I have an Intermatic T104 Timer drawing power from a Homeline Breaker Box for a home swimming pool. I'm wondering whether it would be considered safe to use the knockout in the timer enclosure to ...
3
votes
2answers
140 views

Powering two 3-LED lamps with battery/Battery pack - Multiple questions

I have seen many questions along these lines but I don't think any is an exact match (if that's incorrect, please just point me to the right match, that would be great and save everyone some time). ...