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I would say however that relying on the relay coil is not reliable at all, and there are a variety of somewhat more accurate methods that I would prefer to rely upon.

So a 20 amp breaker is designed to take the load shift on startup. A 15 amp breaker will carry the nominal load, but that surge on startup will kick it every time. In the days before switching supplies the input voltage would vary from 108 to 115VAC where I did work. This occasionally caused breaker trips on the unprepared circuit. I learned to spec high enough to minimize that issue and keep a safety factor in play.

He’s not using a pool side remote box but emulating it. But what if he wanted to use both? At the moment it’s simulating the buttons. What if you need to both simulate the buttons and also read them if they are pressed?

Where I do agree that it is under rated, as far as I know, Mathias is an electrical engineer. So he should be able to work with mains, and he should also know better.

The stakes are much higher when you’re connecting your project to the house mains, though, as [Mattias Wandel] recently learned when the solid-state relay controlling his water heater failed, with nearly tragic results. With aplomb that defies the fact that he just discovered that he nearly burned his house down, [Mattias] tours the scene of the crime and delivers a postmortem of the victim, a Fotek SSR-25DA. It appears that he mounted it well and gave it a decent heatsink, but the thing immolated itself just the same. The only remnant of the relay’s PCB left intact was the triac mounted to the rear plate. [Mattias] suspects the PCB traces heated up when he returned from vacation and the water heater it was controlling came on; with a tank full of cold water, both elements were needed and enough current was drawn to melt the solder build-up on the high-voltage traces. With the solder gone, the traces cooked off, and the rest is history. It’s a scary scenario that’s worth looking at if you’ve got any SSRs controlling loads anywhere near their rated limit.

CARLO GAVAZZI is proud to announce the launch of the newest addition to its RGC Series Solid State Contactor platform. These single-phase zero-crossing relays, featuring an integral heat sink, offer the best in the class current rating of up to 37AAC at 40°C or 43AAC at 25°C.

Depends how far north you are – direct sunlight isn’t required for them to produce useful heat. If you’ve got a months long night then they’re no use though.

Agreed, this is a house fire waiting to happen and your insurance co. won’t give you a cent if an investigation points to this homecooked thing as the firestarter. There are numerous commercial alternatives which are small enough to fit in a junction box _and_ are UL/FCC/CE approved. Granted, they aren’t as cheap as the ESP module and the triac described here, but in the end, most cheap alternatives to switching powerful currents turn out to be very expensive after all.

NO. 10 ON A 50-A BREAKER: The data tag and the wiring of the air conditioner in Orr’s home, which includes a No. 10 wire on a 50-amp breaker.

The TLDR; is – “In high voltage systems clearance according to EN60065:1994, 3 mm is required for Class I and for Class II, 6 mm is required in mains operated systems (240VAC)”

This dead-screen issue was so pronounced that I found myself dropping back to 6 fps rather than 10 on the A55, and shooting in short bursts at what I thought (hoped?) were the decisive moments. More than with many cameras with lesser speed or buffer capacity, I found myself shooting to manage the camera’s buffer, more than simply focusing on the subject and the action taking place. It would have been a lot less aggravating if I could have at least seen thumbnails of just-captured shots immediately after taking them.

My testimony : 230VAC doesn’t kill if you’re lucky. Lots of people died on 230VAC (Claude François….)