The end of Instagram as we know it is here | 19mm Momentary Push Button

There is a lot there, but here are two highlights that directly apply to you as an HVACR professional. This comes from the 2017 edition of the NEC NFPA 70.

Point taken. Perhaps it’s time to change of the the mindset, of the at large DIY community to when treated with properly 120/240 VAC can be used safely, as it’s being used day in and say out. I recall a project of Limor Fried made a project more as need be be becase she appered to be overly frearful of line voltage, then again she was taking into consideration the carelessness in the hacker community. One the flip side I personally know electrical engineers with decade in the filed who flippantly say 120 VAC can’t kill you. I know enough to know they are being full of shit In the end because of irritation fear useful resource is being ignored. Then again I have history of being comfortable with working on motor controls with neatly 800 VAC feeding them or working with electronic devices that have more than 30,0000 volts inside the cabinet. Lower voltages bring greater safy to life burt rquire higher current to do the amount of work, potetiall a fire hazrds id something goes wrong.

One of the most important rules ever: “Never underestimate your own stupidity.” Knowing perfectly well how to safely power down a circuit / appliance / machine is sadly not sufficient to actually do it, especially so if it has become a repetitive task and there are elements of distraction. If ones life is at stake, there should be check-lists written in stone, just like in aviation.

It’s the same with larger, more power hungry projects as well. [Nerd Ralph] has been running a mining rig for a few years now, and has learned just how important proper power supply management can be. His strategy involves using interlocks to ensure everything powers up at the same time to avoid feedback problems, running a separate ground wire between all GPU cards and the PSU and running the supplies at 220 for the NA folks.

1. 25A for 22A? Too close for my comfort. 2. A thin sheet of aluminum is not much of a heat sink. 3. Sitting on top of the hot water heater means ambient temp is going to be a bit higher. 4. Summer in a garage is likely to get hot.

So China are stuck before capitalism’s stable period, the West are now past that. China might end up passing through it, or skipping it altogether. Actually the West might end up learning a few tricks from them.

Mains powered heated glass plates are common place in catering, same deal as a car back window, the heating wires are on the other side from the “working surface” these things can tolerate touching and even fluid spills, why reinvent the wheel, the solution is already commercially avaliable.

It happens to the best of us. We power up our project and immediately run into issues. Be it spotty communication or microcontroller reset or any number of bugs that have us mystified and picking though our code… only to find that it’s a power supply issue. Anyone who has tried doing Raspberry Pi stuff and depended on the USB power from their PC has certainly been bit by this.

Level-2 isn’t required for charging at home, but it sure makes life a lot easier. I wouldn’t use or recommend using a standard outlet for Level-1 charging unless it’s a dedicated circuit with it’s own breaker. With the larger battery packs these days Level-2 charging is becoming more popular if not necessary. Consult your electrician, but I personally think pulling wiring that will handle less than 50 amps is a waste of time. You can use a smaller circuit breaker, but the wiring needs to be robust. Most modern homes built in the last 10 years or so should have a 200 amp panel anyway, so you aren’t going to notice an EV plugged in. Again, consult a qualified, licensed electrician. Also, before you let your ‘handy’ brother-in-law install your charging station, be aware if there is a fire from improper installation, your home owner’s insurance will most likely NOT pay for the event.

When building my printer, I also didn’t like the then state-of-the-art heated PCBs. Thus, I ordered a bespoke silicone heater mat from China, mains voltage, 400 Watts of heater power. Add an aluminium plate to the top and ground it, and safety will be sufficient. I use an SSR embedded into a wall-wart form factor project case with plenty of snubber circuits. Cons: More expensive than a PCB Pros: Heats up incredibly quickly, reasonably priced, won’t get damaged by prolonged high temperature, easy to make non-life-threatening.

I like the idea, but you don’t need a 3D printer for this. Just use conductive strips or good ol’ fashioned wire.

Considering the existence of deep subzero freezers, it would still perform better than a resistive element. Or have it draw the heat from the indoors and run some crypto miners to make up for it.