Electrical Engineering Stack Exchange
Electrical Engineering 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.

Electrical Engineering can often involve high voltages, high currents, and other aspects that can have decisively negative effects on the health and lives of yourself and others.

Questions can range from the safe use of a part or device (within the scope defined in the help center.), safety protocols in Electrical Engineering, and how to fix a dangerous design.

recommended reading

The Fatal Current
Effects relative to voltage, current, frequency, time of exposure

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How much current can I draw from the Arduino's pins?

What's the maximum amount of current which I can draw from each of the Arduino's pins without tripping any of the internal fuses? Is there a limit per pin as well as an overall limit for the whole board?
berry120
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Using clothesline steel core wire rope for AC and DC

As I am currently in a war zone, I don't have many options for cabling. I found this clothesline (steel core plastic wire rope) that appears to be one mm of diameter (steel core diameter.) 13 meters of it measured 7 ohms resistance. Edit: It is 3.8…
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How much voltage/current is "dangerous"?

Related: Safe current/voltage limit for human contact? From what I've heard: 110 V (or 220 V; household voltage pretty much) is dangerous (i.e. can kill you) I think there's consensus on this, no need to try :) 60 V (old telephone lines) is…
user541686
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Can a bird, previously at earth potential, get electrocuted by landing on a powerline at high-enough voltage due to the initial "equalization charge"?

At the voltage levels of typical overhead transmission lines in the US, a bird can land on one and be just fine (as long as it doesn't do something like spread its wings and touch a tree or something else at lower electric potential). However, what…
etherice
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How is using a transformer for isolation safer than directly connecting to the power grid?

How is using a 1:1 transformer safer than using the mains straight off? Is it because you can limit the current coming from the transformer whereas straight from the mains its not current limited? I fail to see how its "safer" when playing with…
Dean
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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 but cannot do so because if the wire hits the…
S. Rotos
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What kind of components in a computer power supply can explode loudly?

Today I heard a loud bang that tripped the circuit breaker in my server room. It must have been really loud because I could hear it 2 rooms away through 2 heavy doors and it was like a firecracker going off right next to me. Long story short, it…
user81993
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How safe is 48V DC?

In many Power over Ethernet (POE) setups the transmission voltage is 48V or slightly more. While higher voltage has obvious efficiency advantages, how safe it is? Is there any risk of electrocution when accidentally exposed, in particular to…
Petr
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What is / how can I get a student-safe power supply for electronics projects?

What is / how can I get a student-safe power supply for electronics projects? I'm looking for a student-safe power supply for solder less breadboard. I'm developing a course to teach electrical engineering to grade school students as an…
JJ Rohrer
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Safe current limit for human contact?

What's the point below which electrical current is generally considered safe for "casual" human contact? Is either voltage or amperage more "dangerous" (e.g. high voltage / low amperage vs. low voltage / high amperage), or is the only consideration…
Mark Harrison
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What is an "XY" rated safety capacitor, exactly?

Please help me understand this. In a prominent, 480v, 6kW AC servo drive, across three input phases, three 22mm "XY" class 10nF caps are placed for EMI suppression. Also, from these three phases, three of the exact same "XY" caps go to chassis…
rdtsc
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Multimeter exploded during ACV measurment - What did I do wrong?

simulate this circuit – Schematic created using CircuitLab A DT-830B meter. I bought a new transformer, and I was trying to measure the output voltage. I plugged the probes on 'VΩmA' (not 10 A) and COM. and set it to 750(not 100% sure if i put it…
user100933
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Why is it dangerous use a coiled extension cord?

What aspect of using a coiled extension cord makes it more dangerous than using an unrolled power cord? Many fire safety websites say that an extension cord should not be used while coiled. Is this due to the cord acting as an air core inductor? I…
Hugoagogo
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Is it safe to sleep in the same room with a car battery?

I sleep in the same room with 2 car batteries. I'm not a battery person so I don't know what type they are. I tried looking for voltage but didn't find it printed on the battery. They're standard acid batteries, I use them to power LED lights and…
MichaelX
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Why are Edison screws allowed to be used?

Why are the Edison screws allowed to be used? They seem unsafe. Why are they designed that way? They require a complete grounding system to ground devices for the rare situation where the hot wires somehow touches the metal case of the device While…
Ronen Festinger
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