> Many relays you find on amazon and similar marketplaces are CE or likewise rated. The tutorial got them from AliExpress. The links are long-dead, but if they

> Many relays you find on amazon and similar marketplaces are CE or likewise rated. The tutorial got them from AliExpress. The links are long-dead, but if they have any ratings they are almost certainly fake. Also, CE ratings apply to finished products - they don't make sense for individual parts. > Add a quick blow fuse to the circuit if you are skeptical of the thresholds. ... which the tutorial didn't do. > I would also say if you sat through a primary school science curriculum, it doesn't take a "loooot of research" to understand the basics of residential electricity. Fifteen year old students learn it in vocational technology courses. That's the problem: this isn't basic residential electricity! You're building a new device, without all the mandatory safety precautions you'll find in off-the-shelf products. The most dangerous part is that at first glance it looks fine, while it's actually violating some quite basic design rules.