What’s a good resource for learning about electrical engineering for people starting from nearly zero knowledge? I’d love to learn more so I don’t burn my house down if I want to, say, replace a light fixture in my house.
Comment on The clueless people are out there among us
MystikIncarnate@lemmy.ca 3 weeks agoOh this gets stranger.
It’s usually 120v, but I’m not going to split hairs over 10v.
So, 120v is not a voltage that is delivered from the grid… Technically speaking. Each home is given one circuit of 240v, which is usually part of one leg of a three phase, coming off of the Transformers… 120v is there because they center-tap the transformer. This halves the voltage by consequence. Inside the house the circuits are generally laid out to try to balance the load between each half of the 240v phase.
The idea is that two 120v loads, put in series, will total 240v. So power will ideally go from L1 to a 120v load, to “neutral”, then over to another 120v load, then finally back on L2.
More or Less.
120v is basically just half of what you should be loading the system with.
The center tap neutral from the transformer is to collect any load imbalance between L1 and L2 to allow for the two “sides” of the phase to be out of balance and still work.
The US “plug” ( aka receptacle ) is a NEMA 5-15R, or NEMA 5-20R (for 20A); these are designed for 120v operation using the half phase described above. Of course, you can mis-wire it and make all kinds of dangerous abominations if you so choose. There is, however, a less known NEMA 6-15R and NEMA 6-20R that is basically the same, but for 240v operation, replacing the neutral wire with L2 instead (and 15/20A respectively).
So it is entirely possible to have 240v outlets in a North American home, while still being compliant with code.
It’s actually really fascinating information when your dig into it.
slingstone@lemmy.world 3 weeks ago
MystikIncarnate@lemmy.ca 3 weeks ago
I’m not an EE. I apologize if I gave that impression. I just have an obsession with understanding anything I use on a regular basis, whether computers, smartphones, electricity, vehicles… Anything that does stuff, and I use it, I want to know how it does the thing that it does.
I’m weird like that.
I learned a lot from “Electrician U” on YouTube, along with a few others. Maybe worth a look. The scientific/physics side of things was more from watching other YouTubers (as to why it behaves the way it does), along with a fundamental knowledge that I learned from doing amateur radio stuff. Working in IT and having to deal with the power requirements of systems and making sure that we won’t blow a breaker under load… That helped motivate me to learn.
It all came to a head when we were deploying a network and server for a business that was still in construction of the facility. The electrician was going to run a temp line for our stuff so we could set up and be ready for opening day, and he asked how many amps we needed… I did a bit of a deep dive to figure out an answer for him, and I’ve been learning more and more since then.
slingstone@lemmy.world 3 weeks ago
Cool. Thanks for the direction. I’m curious about electrical stuff, and I’d like to be able to do some things around my house. There’s some DIY stuff online, too, involving building projects from old parts of appliances that interest me, but I realized quickly that I’d need some very good knowledge about electrical work to stay safe. It’s unlikely I’ll actually pursue the latter, but I’d like to at least know the how and why of my home wiring.
MystikIncarnate@lemmy.ca 3 weeks ago
My recommendation is to maybe get some electrical safe tools, possibly some gloves that insulate against shocks, but definitely a good non-contact voltage detector, or NCV.
Check the circuit with your NCV before turning off the power, before working on the things on the circuit, and after turning on the power when you’re done (before you switch anything on). It helps keep you and your house from halting or catching fire.
… And always connect ground wires first.
Good luck.
pupbiru@aussie.zone 3 weeks ago
i hate that that’s a thing for you
MystikIncarnate@lemmy.ca 3 weeks ago
Fair enough.
If you’re not an EE or a nerd (like me), then it might as well be black magic.
Powerline adapters are fun here tho. They work great if you’re not crossing the split phase, otherwise they suck… A lot.