Cheap Amazon Switches From a Fire Safety Perspective

[DavidWJohnston]

I posted this a while back: https://forums.servethehome.com/ind...-switch-circuit-board-charring-burning.46568/

It's unfortunate because as switches they actually worked amazingly well, and have an excellent admin GUI.

I suspect with a proper power supply without such a large stray voltage it would be OK. After thinking it over I also believe grounding the case would actually help, unlike what I originally stated in the post.

Also FR4 (circuit board material) in a metal case is unlikely to spew flames and burn a building down - It will probably just make terrible-smelling smoke. But who knows. With PoE and higher-power devices the stakes are higher.

In any case, I would recommend getting an NCV tester (non-contact voltage tester) to check for stray voltages around your equipment, and eliminate any problems you find. In my case my Bell Fibe (FTTH ISP) modem induced a surprisingly large stray that put 120VAC on all of the Ethernet ports.

 

[blunden]

I haven't actually had a chance to replace the plug and give one a try. I might not for a while, as shortly after I bought the alternate PSUs, I won an auction for an EnGenius ECS2512F switch (8 2.5Gbps RJ45 ports, 4 10Gbps SFP+ ports). While not the PoE version, I plan to pick up a couple 2.5Gbps-capable PoE injectors and just use that switch instead, as I have more faith in EnGenius and their hardware (I use their APs at home) than what I'm using now.

Nice! It's far too large for my setup, but if you have the space for it I would use it too. Its software is also likely a lot more polished.

 

[blunden]

I posted this a while back: https://forums.servethehome.com/ind...-switch-circuit-board-charring-burning.46568/

It's unfortunate because as switches they actually worked amazingly well, and have an excellent admin GUI.

I suspect with a proper power supply without such a large stray voltage it would be OK. After thinking it over I also believe grounding the case would actually help, unlike what I originally stated in the post.

Also FR4 (circuit board material) in a metal case is unlikely to spew flames and burn a building down - It will probably just make terrible-smelling smoke. But who knows. With PoE and higher-power devices the stakes are higher.

In any case, I would recommend getting an NCV tester (non-contact voltage tester) to check for stray voltages around your equipment, and eliminate any problems you find. In my case my Bell Fibe (FTTH ISP) modem induced a surprisingly large stray that put 120VAC on all of the Ethernet ports.

I think I saw that picture from your other thread in a review on AliExpress.

Now that I replaced the PSU included with my Hasivo switch, which was certainly the most sketchy one I had, all my network equipment has PSUs from high quality PSU brands like Mean Well, CWT and FSP so it should presumably be fine. Technically I haven't replaced the Dajing PSU from my latest Qotom box with the Mean Well unit I ordered for it yet, but I'll do so the next time I reboot it. At least Dajing is willing to put their brand and full company name on it, so in my mind the regulatory marks are more likely to be real.

The Hasivo PSU has at least one highly questionable regulatory marking (looking up the regulatory filing number for the Singapore Safety Mark returns an expired marking for an old LiteON PSU), and also has regulatory markings for some of the Nordic countries as well, which is highly unlikely for a PSU from China where the manufacturer also decided to be anonymous. Also, if you fake one regulatory mark, why not just fake all of them?

Why do you need a "modem" for a fiber installation btw? Do you mean an ONT or media converter?

 

[DavidWJohnston]

@blunden Yeah it's an XGS-PON ONT, "modem" is still common parlance in consumer circles, maybe it's a Canadian thing, I don't know.

I did post a review on Aliexpress with the same pic, I felt sort of bad doing it because they worked so well, but I think it's important. And when I asked for a replacement they sent me a ChatGPT explanation of why grounding is important which irritated me just enough to post it.

I need to get one more DIN-mount 12V PSU to replace the last of my crap AC adapters, but I've long-since fixed the stray voltage problem. I have a couple Mean Well adapters I use for older Raspberry Pi which are power demanding, and they've always worked well.

 

[blunden]

@blunden Yeah it's an XGS-PON ONT, "modem" is still common parlance in consumer circles, maybe it's a Canadian thing, I don't know.

I did post a review on Aliexpress with the same pic, I felt sort of bad doing it because they worked so well, but I think it's important. And when I asked for a replacement they sent me a ChatGPT explanation of why grounding is important which irritated me just enough to post it.

I need to get one more DIN-mount 12V PSU to replace the last of my crap AC adapters, but I've long-since fixed the stray voltage problem. I have a couple Mean Well adapters I use for older Raspberry Pi which are power demanding, and they've always worked well.

I guess I just rarely hear people mention modems when they talk about fiber, and when they do it's usually a misconception causes them unnecessary confusion.

How did you fix the stray voltage problem? Using that USB cable you mentioned?

12V PSUs seems to be widely available and relatively cheap, even from good manufacturers. 54V PSUs in the 100+ W range seem to be much less common however, at least if you want them for a decent price. I had to import a used one from the US, which roughly doubled the cost of the eBay sales price. Still, it's better than paying $90-100 or more for a brand new unit.

 

[jabuzzard]

Yeah, and a meteor could strike the earth and wipe out all life. I actually think the likelihood of an asteroid wiping out all life is much greater than the likelihood of a network switch burning down your apartment.

Cheap finest Chineasium PSU's can and *DO* burn down people's houses on a *regular* basis. In the UK, the London Fire Brigade attend multiple house fires a month, started by dodgy PSU's and chargers. While the actual chance is low, it is at least 10 orders of magnitude more likely than an asteroid wiping out all life. Something that has never happened in Earth's history as far as we know.

 

[blunden]

Cheap finest Chineasium PSU's can and *DO* burn down people's houses on a *regular* basis. In the UK, the London Fire Brigade attend multiple house fires a month, started by dodgy PSU's and chargers. While the actual chance is low, it is at least 10 orders of magnitude more likely than an asteroid wiping out all life. Something that has never happened in Earth's history as far as we know.

Yes, dodgy chargers are a common source of fires here in Sweden too from what I've heard. It stands to reason that dodgy PSUs would pose a similar risk.