Home Assistant Whole House Power Monitoring: NZ Options

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evilengineer

466 posts

Ultimate Geek

#289265 24-Aug-2021 09:51

I'm keen to give the new energy monitoring/management functionality in the latest Home Assistant update a crack which means coming up with a suitable method for measuring whole house power consumption at the meter.

The most elegant method looks to be a Shelly EM which uses a clamp around the incoming power cable.

It can also monitor two separate power clamps which could be used to measure the power generated by a potential future solar panel array.

But is it okay to use one of these in New Zealand?

I can't find a certification specific to the Shelly EM but the link below seems to suggest it's all good based on its EU certification.

http://onesecurity.co.nz/shellyem/

Any thoughts on whether this is correct?

The alternative seems to be a DIY device that counts the flashes from the blinking light on the front of the smart meter.

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190 posts

Master Geek

#2765776 24-Aug-2021 09:55

If that supplier is willing to supply a SDOC, then you should be all good.

I like the look of Cirtcuitsetup for use with Home Assistant, a little bit DIY though.

chevrolux

4962 posts

Uber Geek
Inactive user

#2765809 24-Aug-2021 11:09

Stand to be corrected, but I think the "EM" is end of line now, and you should look at the 3EM.

3EM just uses current clamps, and can monitor either 3 phase, or 3 seperate single phase circuits. So you could have one on the main feed out of your meter, and then the other two could be on hot water, or heating or whatever. Plus DIN rail mounting so tidy and all that.

Not sure on the rules of connecting in NZ. But it just needs 230V to power it, and then the clamps are just that.. clamps. So not actually wired in to anything too serious. But looking here... https://shelly.cloud/knowledge-base/devices/shelly-3em/ I don't see the AS/NZ declaration, so I'd assume not legal? Up to you I guess if you want to take the risk. Its got the EU one though soooo......

davidcole

6037 posts

Uber Geek

Trusted

#2765868 24-Aug-2021 11:29

I tried one of those pulse counters....it means introducing something into the electrical box.....in my case I'd just put in a plastic blacked out lid with teh light detector in it and left the d1 mini outside of the distribution both. It was little ugly though, and obviously needed a power plug close by.

Previously known as psycik

Home Assistant: Gigabyte AMD A8 Brix, Home Assistant with Aeotech ZWave Controller, Raspberry PI, Wemos D1 Mini, Zwave, Shelly Humidity and Temperature sensors
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evilengineer

466 posts

Ultimate Geek

#2765936 24-Aug-2021 12:20

chevrolux:

Not sure on the rules of connecting in NZ. But it just needs 230V to power it, and then the clamps are just that.. clamps. So not actually wired in to anything too serious. But looking here... https://shelly.cloud/knowledge-base/devices/shelly-3em/ I don't see the AS/NZ declaration, so I'd assume not legal? Up to you I guess if you want to take the risk. Its got the EU one though soooo......

I'm not the one that needs convincing. It's the tame sparky needed to fit it in the meter cupboard. 😀

More than happy that something with a CE certification designed for the EU market won't burn the house down given that they run the same voltage as us.

RedactedRetracted

96 posts

Master Geek

#2765943 24-Aug-2021 12:34

Depending what region you're in, your meters might use their own peer-to-peer network (rather than the mobile network that most meters use), in which case you could use an inexpensive RTL-SDR reader and something like this to monitor it: https://github.com/bemasher/rtlamr

However, I think most meters in NZ use the mobile network, so you'll probably be out of luck

evilengineer

466 posts

Ultimate Geek

#2766033 24-Aug-2021 15:03

99% sure the meter calls home using the mobile phone network.

It's a shame "smart meters" are so half arsed here.

davidcole

6037 posts

Uber Geek

Trusted

#2766079 24-Aug-2021 16:37

evilengineer:
99% sure the meter calls home using the mobile phone network.

It's a shame "smart meters" are so half arsed here.

Our meters aren’t smart. They’re just remote readable.

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evilengineer

466 posts

Ultimate Geek

#2766142 24-Aug-2021 18:06

Potentially a silly question, but given it's designed to run directly on a 230V AC supply what's to stop you from wiring the L and N terminals to a standard power chord and just plugging it into a nearby socket?

Not elegant, but could avoid a potential reluctant electrician scenario. 😉

mattenz

190 posts

Master Geek

#2766146 24-Aug-2021 18:15

Regardless, it should in principle be certified if it's being plugged into 240V.

evilengineer

466 posts

Ultimate Geek

#2766158 24-Aug-2021 18:37

Which it is. Has a CE mark to prove it.

I ran a UK purchased washing machine and dishwasher than came over in the shipping container with the furniture for years until they died of old age without any issues whatsoever.

mattenz

190 posts

Master Geek

#2766165 24-Aug-2021 19:28

Well yeah, I'm not saying that stuff certified overseas will have issues here, just letting you know the principles. You don't need an electrician to install your washer dryer, so it's a bit of a moot point. Yes, you could install it yourself, I'm sure that the risk would be marginal.

Firstly, the CE label proves nothing, it is the certification report that is behind it that is the 'proof'. The label itself is whacked on every piece of rubbish that comes out of China. What you need in NZ for devices being certified under mutual recognition is a Supplier Declaration of Conformity, which should be provided by the supplier.

An electrician might install one without certification I suppose, but then it's on him, and he's probably not going to just do the job on the basis of a CE label.

Also see https://www.geekzone.co.nz/forums.asp?forumid=141&topicid=214913

Bewildered

106 posts

Master Geek

#2766548 25-Aug-2021 15:33

I recently had a sparky install a 3EM as part of some other work I needed to get done in the meterbox. He just installed it, no questions asked. Apparently it's reasonably common these days to install a power monitoring solution for a customer.

As for the device itself it works fine, no issues at all. I'm not use the relay function, just have the three clamps on the cables I want to manage. It's even pretty accurate which is nice. Integrates straight into HA with CoIOT (rathern than cloud / MQTT). I mash the data using template sensors as I need to split my reading up so I don't double count - I have one phase in, but also measuring HW and Heating, which I don't want add up together so I get the following:

HW = HW

Heating = Heating

Everything Else = Phase In - HW - Heating

With a bit of tinkering fits straight in the Energy Management. The only issue I had was that from time to time the reading drops to 0 and then comes straight back (mostly HA restarts) but for the purposes of 'metering' this results in a sudden 'spike in usage' which can completely muck up the reading...this is a 'feature' of the utility meter function in HA which is apparently there as some users have meters that report in only once an hour/day so big jumps are expected...there is no option to change this. So I have a pre-filter in the form of another template sensor that won't accept 0/NaN. Since I put that in I've had no problems. :-)

ANglEAUT

2327 posts

Uber Geek

Trusted

Lifetime subscriber

#2766578 25-Aug-2021 16:50

Bewildered:

... so I get the following:

HW = HW
Heating = Heating
Everything Else = Phase In - HW - Heating

With a bit of tinkering fits straight in the Energy Management. The only issue I had was that from time to time the reading drops to 0 and then comes straight back (mostly HA restarts) but for the purposes of 'metering' this results in a sudden 'spike in usage' which can completely muck up the reading...this is a 'feature' of the utility meter function in HA which is apparently there as some users have meters that report in only once an hour/day so big jumps are expected...there is no option to change this. So I have a pre-filter in the form of another template sensor that won't accept 0/NaN. Since I put that in I've had no problems. :-)

Very cool

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eonsim

398 posts

Ultimate Geek

Trusted

#2766687 25-Aug-2021 20:30

For the whole house metering we have a proper smart meter linked to our solar system, that provides a rest-based local API which Home assistant can query. It's possible there are some standalone versions that don't need a inverter, so might be worth talking to a couple of local solar installers and see if they would offer one with out a solar package.

evilengineer

466 posts

Ultimate Geek

#2767029 26-Aug-2021 14:29

Bewildered:

I recently had a sparky install a 3EM as part of some other work I needed to get done in the meterbox. He just installed it, no questions asked. Apparently it's reasonably common these days to install a power monitoring solution for a customer.

Where did you source your 3EM from?

eonsim:

For the whole house metering we have a proper smart meter linked to our solar system, that provides a rest-based local API which Home assistant can query. It's possible there are some standalone versions that don't need a inverter, so might be worth talking to a couple of local solar installers and see if they would offer one with out a solar package.

Solar is on the road map but will probably still be a few years down the track, mostly waiting for house batteries to get cheaper.

How best to monitor that is no doubt a whole separate conversation in itself.

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