# Cheap (ish) energy monitor **URL:** \ **Category:** Devices\ **Created:** [February 23, 2020, 8:09pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318 "2020-02-23T20:09:01Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![vaderag](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/vaderag/32/150_2.png) [@vaderag](https://community.homey.app/u/vaderag)\ **Post date:** [February 23, 2020, 8:09pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/1 "2020-02-23T20:09:01Z")
I have a Hob that I’d like to detect when when it’s on but detecting the increase in energy usage (as can’t directly wire it) Anything out there that doesn’t cost the earth I have seen the aeotec 3 clamp one but at over £100 it’s a bit dear for what I need it for Thanks! ---
**Author:** ![Igy](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/igy/32/22144_2.png) [@Igy](https://community.homey.app/u/Igy)\ **Post date:** [February 24, 2020, 9:08am UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/2 "2020-02-24T09:08:56Z")
Is it 3 phase installation or its enough to monitor 1 phase. Look on Shelly devices, they have affordable solutions. There is also 3 phase meter coming in march. ---
**Author:** ![vaderag](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/vaderag/32/150_2.png) [@vaderag](https://community.homey.app/u/vaderag)\ **Post date:** [February 24, 2020, 9:22am UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/3 "2020-02-24T09:22:48Z")
One phase should be enough I believe - I just need to know when the hob goes on so that I can turn on the extractor fan - without inline wiring this is the only way I can think to do it… ---
**Author:** ![JPe4619](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/jpe4619/32/9017_2.png) [@JPe4619](https://community.homey.app/u/JPe4619)\ **Post date:** [February 24, 2020, 11:30am UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/4 "2020-02-24T11:30:06Z")
Not sure what a Hob is, but many smart plugs have energy measurement. ---
**Author:** ![vaderag](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/vaderag/32/150_2.png) [@vaderag](https://community.homey.app/u/vaderag)\ **Post date:** [February 24, 2020, 11:43am UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/5 "2020-02-24T11:43:36Z")
> **[What is an Induction Hob and how does it work? | Bosch Home UK](https://www.bosch-home.co.uk/bosch-innovations/cooking-with-induction)** > > What is an induction hob? Discover more including how it works in our handy guide to induction cooking. Explore the quick, safe and clean way to cook It isn’t plugged - it is hard wired to the breaker (via a switched spur) as it’s 32A. Hence the need for an energy reader as I don’t want to mess with the high load directly ---
**Author:** ![Igy](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/igy/32/22144_2.png) [@Igy](https://community.homey.app/u/Igy)\ **Post date:** [February 24, 2020, 2:23pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/6 "2020-02-24T14:23:03Z")
I believe that it uses 3 phase wiring! For this purpose there is no device fully supported by Homey yet AFAIK - [see this post](https://community.homey.app/t/3-phase-energy-meter/14962). I have older Aeon clamp meter that do report overall consumption to Homey, which would solve your problem. Or just wait for [Shelly 3M](https://shelly.cloud/shelly-3-phase-energy-meter-with-contactor-control-wifi-smart-home-automation/) once it will be available (mid March) and supported by Homey (unknown) 🙂 ---
**Author:** ![vaderag](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/vaderag/32/150_2.png) [@vaderag](https://community.homey.app/u/vaderag)\ **Post date:** [February 24, 2020, 2:25pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/7 "2020-02-24T14:25:56Z")
I’m a little confused. What exactly do you mean by three phase wiring? There is one wire with a live, neutral earth which passes to it. Presumably the measurement would just read current flow over the whole wire? Certainly wouldnt need reading on the earth… I used to have a non smart energy monitor and that just wrapped round a cable ---
**Author:** ![Igy](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/igy/32/22144_2.png) [@Igy](https://community.homey.app/u/Igy)\ **Post date:** [February 24, 2020, 2:32pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/8 "2020-02-24T14:32:35Z")
Usually hobs are connected to 5 wires (Live1, Live2, Live3, Neutral and Ground) because of high power load. If its not the case and you have only 3 wires (Live, Neutral and Ground) then [Shelly EM](https://shelly.cloud/shelly-energy-meter-with-contactor-control-wifi-smart-home-automation/) should work just fine. ---
**Author:** ![vaderag](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/vaderag/32/150_2.png) [@vaderag](https://community.homey.app/u/vaderag)\ **Post date:** [February 24, 2020, 2:33pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/9 "2020-02-24T14:33:30Z")
Ah, I didn’t realize. I’ll open up the spur later and take a gander. ---
**Author:** ![Igy](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/igy/32/22144_2.png) [@Igy](https://community.homey.app/u/Igy)\ **Post date:** [February 24, 2020, 2:37pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/10 "2020-02-24T14:37:29Z")
Anyway, in all cases you will need to do some wiring with those meter devices 🙂 ---
**Author:** ![JPe4619](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/jpe4619/32/9017_2.png) [@JPe4619](https://community.homey.app/u/JPe4619)\ **Post date:** [February 24, 2020, 2:37pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/11 "2020-02-24T14:37:34Z")
![image](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/6/a/6adb28812d8588748f427f03715ad75a0820da64.png) ---
**Author:** ![vaderag](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/vaderag/32/150_2.png) [@vaderag](https://community.homey.app/u/vaderag)\ **Post date:** [February 24, 2020, 3:06pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/12 "2020-02-24T15:06:02Z")
I don’t mind doing some wiring, I just don’t want to stick something in the middle of the lead!! There is a plug socket right next to the hob in a cupboard so can wire into a plug for power for simplicity ---
**Author:** ![vaderag](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/vaderag/32/150_2.png) [@vaderag](https://community.homey.app/u/vaderag)\ **Post date:** [February 24, 2020, 3:09pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/13 "2020-02-24T15:09:57Z")
Would a 50A clamp be okay on a 32a lead? ---
**Author:** ![JPe4619](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/jpe4619/32/9017_2.png) [@JPe4619](https://community.homey.app/u/JPe4619)\ **Post date:** [February 24, 2020, 3:12pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/14 "2020-02-24T15:12:42Z")
Sure why not? 50A is the max. current, so 32A is comfortable. ---
**Author:** ![vaderag](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/vaderag/32/150_2.png) [@vaderag](https://community.homey.app/u/vaderag)\ **Post date:** [February 24, 2020, 3:17pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/15 "2020-02-24T15:17:50Z")
So not home yet but the instruction manual of my job recommends H05V2V2-F wire if the original gets damaged. This seems to be 4 core, so assuming it’s 2live feeds, one neutral and one earth…) What I don’t understand is why I’d need to read those separately… If I wrapped one around my incoming house line I’d get usage on the whole house, so if I wrap across both live wires (i.e. the whole wire) then surely I’d get the usage on the whole hob? ---
**Author:** ![JPe4619](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/jpe4619/32/9017_2.png) [@JPe4619](https://community.homey.app/u/JPe4619)\ **Post date:** [February 24, 2020, 3:34pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/16 "2020-02-24T15:34:37Z")
If your house is feed with 1 live wire, then this is true. However when your house is feed with 2 or 3 Live wires (we call that Phases) then the current between the Live wires are phase-shifted and that means they cannot be read wit one clamp. ---
**Author:** ![vaderag](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/vaderag/32/150_2.png) [@vaderag](https://community.homey.app/u/vaderag)\ **Post date:** [February 25, 2020, 7:36am UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/17 "2020-02-25T07:36:28Z")
Yeah, my house is fed with one wire. Presumably that works mean that both live wires would be in phase so I can just use a single clamp on the hob? ---
**Author:** ![Igy](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/igy/32/22144_2.png) [@Igy](https://community.homey.app/u/Igy)\ **Post date:** [February 25, 2020, 1:28pm UTC](https://community.homey.app/t/cheap-ish-energy-monitor/26318/18 "2020-02-25T13:28:20Z")
Best way to check this is to open the hob connection box to see the wiring. If only 3 cables are connected to it (Live, Neutral, Ground) then Shelly EM + 1 Clamp will work just fine.