@zetasyanthis exactly what sort of project are you using this for?

@Felthry Essentially a box that lets me test mains appliances more safely. I've got a beefy input filter and ceramic fuseholder, an NTC, an AC (analog :D) ammeter, and a GFCI. mpja.com/IEC-Power-Inlet-Modul

@Felthry I don't remember if you're in the US or not, but we don't have RCD/GFCI protection on most outlets. That was the main purpose, to protect against me providing a path to earth accidentally. :P

@Felthry The rest is just because less bangs is good. (Oh, and I forgot the power on indicator light.)

@zetasyanthis "less bangs is good" -> you're clearly not an emo then :P

@Felthry More like, I want to limit the amount of magic smoke a device I'm testing might emit in the first few seconds, hence the NTC and input chokes. (Plus that'll prevent me feeding back goodness knows what onto my power lines.)

@zetasyanthis Are you familiar with what's called a LISN? (yes, pronounced "listen")

@zetasyanthis okay! Just asking because plenty of engineers don't know what that is either. Thought it might be handy to add to your box in place of the input chokes you mentioned, so you have a defined point for noise measurement if you want that.

@Felthry Nah, that I don't care about in this instance. This is mostly "Okay, I've repaired the power supply in appliance X. Let's plug it in and hope it doesn't go BOOM."

Follow

@zetasyanthis Hmm. I wonder if they make adjustable circuit breakers. That would be a neat feature for a box like that. Have a circuit breaker you can configure to trip at a little above the current your thing expects.

Actually, if you don't know what you're going to be plugging into this thing, are you sure that ICL won't be a problem? They don't drop to their minimum resistance if you don't give them the rated current.

@Felthry That's in fact the idea. I almost made it bigger and put a couple high wattage power resistors in series too, but the cost + heatsink + cool was quite high. :)

@Felthry Mainly it's there in case I end up with a mains short. Should prevent a huge spark/arc and then the HRC fastblow fuse behind it will nuke the circuit.

@Felthry Yeah. The goal is that if I do something stupid it should save my life (GFCI), prevent damage to itself, and minimize damage to the appliance.

@zetasyanthis Just remember a GFCI won't save you if you're gripping both live and neutral!

@Felthry Yes of course! I think you saw the pliers I have the other day... Only use one hand when poking things that might be live unless using those.

@zetasyanthis Are those properly insulated? A lot of pliers look insulated but aren't rated for that kind of stuff.

@zetasyanthis good!

I should add stuff on tools to that document that started as package recommendations for hand-soldering...

@zetasyanthis Something else to consider for this: transformers can be remarkably good at preventing too much current flowing, especially air-gapped ones like those used in microwave ovens.

@Felthry NTC is 6A, fuse I'm putting in is 5A max. (Input chokes rated to 6A too.)

Sign in to participate in the conversation
Awoo Space

Awoo.space is a Mastodon instance where members can rely on a team of moderators to help resolve conflict, and limits federation with other instances using a specific access list to minimize abuse.

While mature content is allowed here, we strongly believe in being able to choose to engage with content on your own terms, so please make sure to put mature and potentially sensitive content behind the CW feature with enough description that people know what it's about.

Before signing up, please read our community guidelines. While it's a very broad swath of topics it covers, please do your best! We believe that as long as you're putting forth genuine effort to limit harm you might cause – even if you haven't read the document – you'll be okay!