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Shelly EM - first install - direction of Electricity Flow - Clamp 120A

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Yesterday I installed my Shelly EM and I just wanted to test to see how it would work so I could eventually use it at another property to monitor the electricity usage.

However I quite like it so will keep it where it is and purchase another one.

I was unsure which live cable to hook it up to but decided on the bottom one, but am now unsure of the electricity flow, The Arrow on the clamp points from left to right but in hindsight I think the electricity actually flows from right to left (it goes in at the top of the main switch and then. comes out at the bottom)


But it seems I am getting accurate data from the Shelly EM 4.74kWh usage since 4pm yesterday when I installed it, positive voltage of ~240 volts

Reactive Power of -367.5 and PF of -0.69


I have another tool to monitor the electricity usage and it reads my smart meter and it is a cloud service called Hugo

I compared electricity usage from 4pm till midnight yesterday and it is matches the 4.74kWh reading by Shelly perfectly (it gives me 4.8kWh)

Btw this is the first time I have opened the fuse board and it is not the prettiest one I have seen, full of cobwebs as well, will give that clean but am not going to redo any wiring

At least everything is labelled properly

Let me know what you think about the flow of electricity, I tried to find a wiring diagram / instructions of the Legrand main switch to figure out what the numbers 1,2,3 and 4 mean, 1 and 2 being live and 3 and 4 being neutral but was not succesfull

Thank you


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From the looks of it seems fine to me: The Main switch is a double pole Isolator breaker. From what I know it is just an on-off switch for both Phase and Neutral. This then goes into the RCB Switch that provides power to the remaining breakers. How each component works I am not sure I'm sure we have a Electrition on the forum that might shine light on this question 

I found this PDF of the Isolation switch you might have https://assets.legrand.com/pim/NP-FT-GT/F01677EN-00.pdf



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Thank you, the diagram is helpful, and I now better understand the layout of the fuseboard.

I  zoomed on another picture I took of the clamp, and the arrow is pointing from K ---> L from right to left and not left to right as I had initially thought, so everything does seems to be accurate.


The reading from the electricity supplier (via the hugo app) and the Shelly EM are very identical although the Shelly EM readings are a bit lower than the electricity supplier

Looks like I am all set!


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