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Comment by stavros | Hacker News Reader

I got a Zigbee power breaker and hooked it up so all my flat's power goes through it, and then made an e-ink display to show my power consumption:

https://www.stavros.io/posts/making-the-timeframe/

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For people in The Netherlands: all Smart Meters that the net maintainers installed (are required to) support the P1 standard, which provides a standardized interface for customers to read out current current draw, cumulative power use, etc. Usually gas is hooked as well.

You can hook up a cheap dongle to expose the stats in an app. For instance, we use:

https://www.homewizard.com/nl/shop/wi-fi-p1-meter/

This meter also exposes an API on the local network. I have written a small driver for the SmartThings Hub, so that you can get the stats/graphs in the SmartThings app as well (we use a SmartThings hub for Zigbee/Z-Wave devices):

https://github.com/danieldk/homewizard-energy

This applies to Finland and Sweden too, perhaps others to follow.

Same principle in Norway, though it uses HAN instead of P1.

They call it HAN here in Finland too, but it's the same interface as the Netherlands one.

Same in France, the official meters have an interface on which you can plug a Raspberry Pi for example to read the data live.

Do you know of an equivalent for the optical ports that speak DLMS/COSEM? The P1 standard doesn't seem to have caught on here in Spain just yet.

It seems that nl ppl always live 20 years into the future.

> all Smart Meters that the net maintainers installed (are required to) support the P1 standard

Does that support monitoring each power circuit separately?

Not likely, you’d need a CT around the phase conductor(s) of every circuit. The meter likely only has CTs around the 2 (3) phase conductors on the incoming service drop.

It is entirely possible to meter each individual circuit, either with CTs and a meter or (gross simplification) special breakers that have metering capability built-in.

Indeed it is great to use what is already provider by the utilities company, for the same reason I wrote a prometheus exporter that exposes the homewizard values https://github.com/chrisdoc/homewizard-p1-prometheus

Or to integrate with home assistant and cheaper

https://www.zuidwijk.com/product/slimmelezer-plus/

I guess I will be able to get this cheap when we finally have smart meters in Germany in like 20 years

I think the aliexpress link for the display is busted (as they do).

A natural integration would be with Home Assistant. I’m not sure if the Earu breaker has an OOTB integration with HA yet, beyond doing something like Zigbee2MQTT and configuring entities for readings. It’s a good pattern though - integrate meter with your automation hub, let the automation hub push the images to displays, for meter and everything else.

That was a great write up! I wish I had the time to follow-up this guide. Thanks for sharing it!

Thank you! It's not very hard to use, you basically just flash my firmware and use my script to display images on the Timeframe. That's about it.

Related to your comment so much, I got hurt

This guy is funny, I like him. I just bought a $12 annual sub to his project IMGZ. I'm not affiliated at all, if you're thinking this is an elaborate ad.

https://imgz.org/

Hey dude, fix your "open in wallet" button when paying with BTC. The link is janked up.

Otherwise, it works great. See https://imgz.org/iAB4tgaJ/

I'm curious, which power breaker do you have?

This one: https://www.aliexpress.com/item/1005005657383634.html?spm=a2...

You're running all your flat's power through that $14 Chinese rubbish and never assumed that shortcuts were taken or quality would be an issue? How do you know it will continue to function as a circuit breaker and isn't just a piece of wire inside?

For the uninitiated, CE marking is meaningless (it allows for self-certification).

I'd like to see Big Clive do a teardown of one of those.

You can get less shit ones that aren't made of Chinesium from Shelly

Great suggestion. Some of their modules appear to be UL certified.

Yeah you need to shop for these specifically. They come at a premium.

Some of them (most of the latest models) are scriptable on-device.

There are some ready-made scripts for the Nordics that check the current electricity prices and use those with some basic rulesets to see if the electric heating in a house should be on or off for example.

I just use mine to turn off the ice machine at 22:00 so it doesn't run through the night :D

> How do you know it will continue to function as a circuit breaker and isn't just a piece of wire inside?

I don't care. I connected my previous breaker after it.

Why not just use a current transformer? (Clamp over wire type) It's much safer.

Do you know of a Zigbee one? That's also a good option.

Some options at the $10 price point on AliExpress, though I cannot recommend one, maybe another reader can. CTs are the generally accepted way to do this and don't have to modify mains wiring. Could also build your own; CTs are inexpensive.

> Why not just

Please learn to never use this type of phrasing when offering suggestions. Your entire exchange was needlessly patronizing and off-putting.

Thanks Dad.

A bit funny, but I personally found "please learn to never..." to be MUCH more off-putting and patronizing than the "why not just...".

Maybe just something about the latter being interpreted as a question, and the former being interpreted as an order.

The fire hazard from the cheap breaker is still present. Your existing one protects the downstream circuit but the Chinese breaker itself is a safety hazard.

You should care about the quality of these devices, especially ones that provide safety.

Just a nit: The Chinese breaker isn't providing safety. You should still be caring about its quality because it's handling a lot of current (and potential power).

> $14 Chinese rubbish

Where do you think the "quality" devices are made?

Quality ones inspect the product and have a company that can be sued. Others change their name monthly.

Somewhere in the EU or UK, normally.

There are 2 ways to design these. They could use a regular relay, or they could use a solid state relay.

Solid state relays have widespread fraud. Like 60% of the ones on amazon will catch fire or fail before they hit the rated current. Trade suppliers generally don't sell them at >30 amps.

Regular relays up to 10 amps are cheap and reliable. Beyond that, they get expensive surprisingly fast, and the reliability is hit or miss. They fail in numerous ways, but the most concerning one is the plastic case melting and catching fire. The chance of failure depends on the nature of the load (capacitive or inductive loads will dramatically shorten a relays lifespan).

In my professional career, I have witnessed ~20 of the above devices failing, with melted bits or burn marks, but of that sample none has burned down a building, yet. But I'd say that was more down to luck than good design.

In general, I would trust a china-device for monitoring power, but not for switching anything more than ~10 amps (1 outlet).

Is it the switching that kills the relay or is it enough to start/stop the load? E.g. if I have a 10A smart plug monitoring power on a small waist-tall freezer in the garage will it eventually damage the switching function?

Its generally the switching, although I wouldn't professionally sign off an undersized relay on the basis of 'it never switches, so its fine'.

The switching under load causes the contacts to get worn, then the large load causes the now-worn contacts to get hot, and the plastic supports melt and catch fire.

A mains connected circuit designed to minimum costs could have all sorts of corner cuts: bad capacitors, no overvoltage protection, no back EMF from load protection, bad isolation to the driving circuit, etc, so that it could work flawlessly for decades, but also stop working after a while because of a spark that welded the contacts together, or mains voltage to enter the driving circuit because of moisture and insufficient creepage between high and low voltage tracks, etc. I use a lot of cheap Chinese products in non critical contexts, but I'd avoid them with mains voltage or in any safety critical use.

I've been down this road quite a bit on Amazon, eBay, and AliExpress/Alibaba. Are there any good options for relays that work for 100-200amps? I've found 30 amp relays of the type that are built into PCBs and I have tried a few 100 amp contractors that can be triggered with a separate line but I'm not sure I trust them. Most tend to top out at 65a rating and I get the feeling the 100a ones are just the same but with a more belligerent seller willing to advertise a false rating. What serious options are available for switching larger loads remotely.

Relays and contactors are the same thing. The main difference is that they tend to be called contactors more often when they are carrying mains voltage and current. (Or higher.)

It's very common to use a relay to control a contactor.

This is NOT a valid 63 Amps rated breaker, or 63 Amp anything for that matter. The screw terminal will melt.

Based on the screw terminal, without looking inside, I would rate it not higher than 10 Amps. Don't pass your whole apartment through it.

I have seen 63 A (and higher rated) equipment, this is not it. This is a fire hazard.

Can you link the power breaker?

This one: https://www.aliexpress.com/item/1005005657383634.html?spm=a2...

It's crazy to run any power through that. Only safe option are current transformers

Do you have any you would recommend? I'll love you for a link, and like you for a brand name. Not being a dick here, I'm genuinely looking for one that I don't have to lose sleep over installing.

Would this work?

https://github.com/magico13/ha-emporia-vue

You can do mains only or every circuit

https://shop.emporiaenergy.com/collections/in-panel-energy-m...

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