How power works in a data center: What you need to know | Lrd12 Overload Relay

Called the MPSMv2, the core of the project is the ESP8266 module. The dev board itself can support anything with GPIO pins, whether it’s an Arudino, Raspberry Pi, or anything else with those features. Flashing the NodeMCU firmware is pretty much all that needs to be done in order to get the device up and running, and once you get the device connected to your WiFi you’ll be able to control whatever appliances you want.

Very nice hack and well documented, safety issues included. For all the rest of the naysayers, you are far more likely to die driving your electric car than from a charger failure yet most people think nothing of jumping in the car despite it being one of the leading causes of death in the US.

The thing about the picture that worries me is the receptacles seem to be mounted below 18 inches from the floor. That is a BIG NO-NO. IF there are any gasoline cans in the garage for an old lawn-mower, etc then he has just created an explosion hazard.

Not really clear but good point. I met an electrician who told me : ‘230VAC is not dangerous, I’m getting shocked a lot, it really hurts when its 400VAC. Oh by the way, I have to get an appointment for my heart !’

I will not put all the money on the bet, but this one might be indeed one of the solutions: http://www.mouser.com/ds/2/328/lnk302_304-306-179954.pdf if you want something “all-in-one”. I prefer a separate external PSU for many reasons, including circuit separation and protection. You can find 5V and 3.3V SMPS DIN rail mouting ones for decent prices.

Unfortunately, by in large, the comments for this article were unnecessarily negative, and downright factually inaccurate.

I am certainly not suggesting HVACR techs engage in performing work outside of their skills or licensures, but, in many cases, being able to identify the problem and making the repair are two different things.

With the primaries wired together, the magnets are epoxy potted, the business end is faced off cleanly, and the whole thing put to the test. [MakeItExtreme] doesn’t go into control details in the video below, but the website mentions the magnet being powered off a 24V 15A power supply with battery backup in case of mains failure.

If you can power the logic side with some +5V derived from mains, there is no point keeping the optocouplers, right? Of course, the ESP would need to be programmed when unplugged from mains A/C, but with OTA, it should be possible to control it all wirelessly once the initial firmware setup is done, even more so with LUA where telnet over wifi can be used once initial setup is done. So now, what kind of circuitry is needed to hash mains A/C to +5V DC (or even better, directly +3.3V)? What’s in a commercial USB adapter? Greg

Thanks for the pointer, it looks promising! The RF-controlled remote switch appliances that can be found for a few dollars are self-contained, I would think that a Wifi-based one could also be? 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.

Of course a safe mains powered heater is possible, but you need a double insulated cable (which is stiffer and heavier) and a reliable strain relief for it. You have to permanently bond the heater PCB to the glass print bed with silicone. You need a fuse and a thermal cut out (thermal fuse) for fire safety, because the available power in the mains circuit is much higher.

Australia is similar, except 3ph is uncommon in a house. There’s 3 phase at the kerb and each house is connected to one phase.