What Most Techs Get Wrong About Wire Sizing | 2017-09-18 | Circuit Breaker Parts

The previous two Mi Mix phones were both pioneering attempts by Xiaomi to reduce the bezels around the screen as much as possible, but they predated the now-ubiquitous notch and compromised by awkwardly placing the selfie camera below the screen, forcing you to hold the phone upside-down or deal with an unflattering angle. Even Xiaomi itself adopted the notch earlier this year with the Mi 8. But the Mi Mix 3 preserves the spirit of the series while seemingly fixing one of its bigger flaws.

One more thing. If you are not a electrician you should not be playing with Live power. Like you said you almost killed your family, And Possibly more people.

Because a failure of the sort I have described will not be current limited. You’ll likely start a fire.

My situation is a good example. I just purchased a new house and unfortunately it does not have a garage. Until I get the garage built in the Spring with a NEMA 14-50 outlet, I’m going to rough it with L1 at 120V/15A.

http://www.mikeholt.com/technical.php?id=grounding/unformatted/GroundResistance&type=u&title=Ground%20Resistance%20-%20It%27s%20Not%20What%20You%20Think%20%2812-30-99%29

Having a separate wire coming out of the box seems like an extra hazard to me. If you keep the thing self-contained with only mains-in/mains-out, I would think it is safer in the end, and removes the internal complexity of optocouplers.

Reading at least the related article and a datasheet before making comments about something is quite a heavy task to ask this days…

But they’d have to be in the same phase for it to work. If they’re in opposing phase, they’ll just push and pull against each other.

Converting mains voltage down to 12 or 24VDC to drive a heating element makes no sense. To get 120 watts at 12 volts requires thick wires that can handle 10 amps, whereas at 120V, tiny 1A wires will do. If you’ve ever felt the MOSFET that switches your heated bed on and off, you know it’s working hard to pass that much current. [Makertum] is of the opinion this is a dumb idea. He’s creating a 110 / 230 V, mains-powered heated bed.

Engineering types have been known to reduce “Preventive Maintenance” in the large “Mains” switch panels in an attempt to save budget funding. A close friend stepped up to a sadly neglected switch panel, pushed the dis-connect and the panel door blew off in his face. It seems that dust is conductive, and will explode if a large spark is present. The good news, he is alive, and was promoted to avoid a lawsuit. :cheers:

Matt Reed, the Creative Technologist at redpepper who shepherded the project, explained via email: “I got all of the Waldo training images from Google Image Search; 62 distinct Waldo heads and 45 Waldo heads plus body. I thought that wouldn’t be enough data to build a strong model but it gives surprisingly good predictions on Waldos that weren’t in the original training set.” Reed was inspired by Amazon Rekognition’s ability to recognize celebrities, and wanted to experiment on a similar system which supported cartoons. He had no prior experience with AutoML, and it took him about a week to code the robot in Python.

I have used a setup like this using two back-to-back “door-bell” transformers (220V to 9V) to play with neon tubes when I was a kid. The current was so low that even a lightbulb wouldn’t turn on. However, it was enough to teach me about electric shock from mains voltage when I have carelessly put my finger across the output terminals …