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My cat water fountain comes with a spicy USB power adapter

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Re: My cat water fountain comes with a spicy USB power adapter

#161

Post by ToucanLoucan »

Kon-Peki wrote: post #158
ToucanLoucan wrote: post #124

Earlier quoted context omitted.

Semi-related: My wife has the little Fallout 4 fridge they dropped a while back, not a proper fridge but one of those peltier plate ones that's only really good for like, soda and beer. She was quite upset when it died one day and I toss it on the bench, and stab the power socket with my alligator clips and give it 9 volts. Worked perfectly so it just needed a new power supply. A quick Amazon order, snip the wire off…

> Turns out, the original power supply had it's polarity reversed. Doesn't that make it a heater, instead of doing nothing?

Nah, the machine was just wired entirely backwards. The +9V off the power supply was connected to 0V inside, and was in fact acting as the 0V with the other delivering the +9V. The wires were marked on the power cable, and were just backwards, so when I snipped and spliced on a new power supply with the polarity correct, it was then reversed inside.

Re: My cat water fountain comes with a spicy USB power adapter

#162

Post by HalcyonCowboy »

terom wrote: post #143
stephen_g wrote: post #119

Earlier quoted context omitted.

That sounds incredibly error prone and actually quite dangerous! At least a lot of AC to DC converters are universal voltage and frequency, but not all appliances! In Australia we have only one voltage that will ever come out of a single phase socket, but the standards took the opposite approach with current ratings - the sockets are cleverly designed in terms of their current capacity so (assuming it’s been installe…

> But a 10 amp plug can still fit and sit snugly in a 15 or 20 amp socket, and a 15 amp can still fit into a 20 amp socket with no problems. It’s pretty clever. That sound dangerous. The larger fuse sized for the 20A socket will not protect the smaller conductors in the cable sized for the 10A plug, they can get overloaded. The three-phase / industrial CEE plugs and sockets used in the EU are sized for 16A/32A/63A/12…

It's not dangerous in practice. Reading through NEC in the US, there's plenty of leeway for mixing ampacity ratings on circuits, within certain limits. For example, it's fine to have 10x 15A duplex on a 20A circuit. It results in less wiring, and allows for logical grouping of circuits. Electrical code starts from the the most common causes of electrical failures, and tries to design down from there. The ampacity ratings on devices and various components of the circuit are designed to reject the common causes of failure, and conductor failure at the device isn't one of them (appliance manufacturers are more likely to get their devices certified, so if there's a failure in the appliance, some other part of the appliance's electrical system will fail before the conductors do).

So the ampacity of the connector (duplex and plug) is meant to reject certain combinations (plugging a 30amp appliance into a 15amp duplex/circuit). It's obviously very easy to get around that by just wiring things together wrong (18AWG wire on a 30Amp circuit), but by design, a 30amp appliance with the proper plug cannot be plugged into a 15amp outlet.

Of course, this is informed by the electrical code in my home country, so I understand that other places and people have different experiences, but electrical accidents have been on a steady downward trend since the 80's, so the NFPA NEC has to be doing at least some things right.

Re: My cat water fountain comes with a spicy USB power adapter

#163

Post by terom »

Tyrannosaur wrote: post #155
terom wrote: post #143

Earlier quoted context omitted.

> But a 10 amp plug can still fit and sit snugly in a 15 or 20 amp socket, and a 15 amp can still fit into a 20 amp socket with no problems. It’s pretty clever. That sound dangerous. The larger fuse sized for the 20A socket will not protect the smaller conductors in the cable sized for the 10A plug, they can get overloaded. The three-phase / industrial CEE plugs and sockets used in the EU are sized for 16A/32A/63A/12…

That doesn't make sense though. The fuses aren't to protect the load; they are to protect the circuit. It's up to whatever device you are plugging in to not draw more current than it can handle. If I have a 3 Watt doohickey, I don't go looking around to find a 0.025A socket, I plug it in to my 15A wall socket and everything works great.

Yeah, the risks mainly come with extension cords, like plugging a bunch of 10A appliances into a single 20A outlet via a 10A rated extension cord with multiple 10A outlets.

Appliances themselves with their own input fuses and captive cables are less risky, although some kind of internal wiring short could still get all melty.

It's true that sizing the plugs that way does prevent you from plugging a 20A appliance into a 10A extension cord, which makes sense.

Re: My cat water fountain comes with a spicy USB power adapter

#164

Post by ChrisMarshallNY »

jdboyd wrote: post #46
wiredfool wrote: post #17

Earlier quoted context omitted.

It's got a CE mark, but it's unclear if it's valid or not. This is a mandatory certification in the EU, like the UL listing in the US. The device is specifying the output voltage, which isn't in spec for the connector, but it is (apparently) accurate.

UL isn't actually mandatory in the US. The only thing mandatory that I am aware of is FCC certification for devices with signals over a certain number of Hz, and they wouldn't care about a USB port being abused.

I read somewhere, that there's no such thing as a UL-approved turkey fryer.

https://www.ul.com/news/put-safety-menu-thanksgiving

I think that is still the case.

Re: My cat water fountain comes with a spicy USB power adapter

#166

Post by mcronce »

cesarb wrote: post #50
can16358p wrote: post #9

Earlier quoted context omitted.

I think when it comes to safety restrictions should be there. The hacker in me hates it too but just imagine if a small portion of standard-looking outlets did not output 220V (or whatever standard you have) and say 330V. Many applicances would break, or perhaps even catch fire. If there were many different USB-A devices and people were used to checking the voltage output before plugging, that might not be needed, bu…

> just imagine if a small portion of standard-looking outlets did not output 220V (or whatever standard you have) and say 330V. We have something like that here in Brazil. On cities which use 127V as the standard voltage (some cities use 220V), you can get 220V by using a pair of phases instead of a phase and the neutral, and it's common to find a few standard-looking sockets which are 220V instead of 127V. They migh…

In my old house (US) there was an outlet that was setup that way. Two phases plus ground on a bog standard looking 120V outlet. Made the discovery when we plugged a 500W work light into it while renovating and it exploded after a few minutes.

Re: My cat water fountain comes with a spicy USB power adapter

#167

Post by arwhatever »

toddmorey wrote: post #107

> The idea of a water fountain for cats may sound odd Cats instinctively love & trust moving water as stagnant water can accumulate bacteria & disease. So a cat fountain sounds like a gimmick or novelty but it’s a great idea.

I bet my cat drinks 500% more water since getting him this fountain, as compared to a still bowl of water.

It’s cute and adorable (the fountain is a bit silly looking), and I have to assume it’s good for him.

And to guard against power outages, I got him a separate fountain with an open top, so in a pinch at least he had some standing water.

Re: My cat water fountain comes with a spicy USB power adapter

#168

Post by JohnFen »

denotational wrote: post #2

This is the sort of thing that almost (but not quite) pushes me to support mandatory certification (enforced by patents/other IP protections) for consumer devices that use a familiar connector like USB. Consumers shouldn’t need to worry about the specific output voltage; the presence of a USB-A connector should indicate that it abides by the specification. The hacker in me hates the idea of enforcing something like t…

> The hacker in me hates the idea of enforcing something like this

Why? I'm not sure what being a hacker has to do with it, but this sort of thing would benefit everybody and harm nobody except for the negligent.

Re: My cat water fountain comes with a spicy USB power adapter

#169

Post by ForOldHack »

wiredfool wrote: post #17
denotational wrote: post #2

This is the sort of thing that almost (but not quite) pushes me to support mandatory certification (enforced by patents/other IP protections) for consumer devices that use a familiar connector like USB. Consumers shouldn’t need to worry about the specific output voltage; the presence of a USB-A connector should indicate that it abides by the specification. The hacker in me hates the idea of enforcing something like t…

It's got a CE mark, but it's unclear if it's valid or not. This is a mandatory certification in the EU, like the UL listing in the US. The device is specifying the output voltage, which isn't in spec for the connector, but it is (apparently) accurate.

The device is specifying the output voltage, in very black, very tiny letters. How convenient. The person who took this almost impossible photograph should get a Pulitzer. No quantitative measurement for the real voltage, or current for that matter.

https://donglec.com/blogs/journal/are-third-party-chargers-h...

Re: My cat water fountain comes with a spicy USB power adapter

#170

Post by jamincan »

toddmorey wrote: post #107

> The idea of a water fountain for cats may sound odd Cats instinctively love & trust moving water as stagnant water can accumulate bacteria & disease. So a cat fountain sounds like a gimmick or novelty but it’s a great idea.

I got one after I noticed how much my cat liked to jump up to the sink and try to drink from the tap while I was using it. He loves it, and anecdotally seems to drink more than he did without.
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