Measuring consumption of a 400v 3 phase load

Energy
#1

Hi,
I’m getting started with energy tracking and for most of my loads it’s pretty straight-forward using a combination of Shelly plugs and PM1s. However, I have a sauna that I would like to also track the consumption of, and it is a 3phase 400v system. I have been unable to find equipment which can take that voltage. I was looking into the Shelly EM3, but while it would work in terms of amps, it is also rated 230v.

Does anyone know of hardware that can take a 400v load and measure its energy consumption?

Thanks!
Bastiaan

#2

Shelly em3 can monitor all 3 phases, its good for your use case. Its just being powered by one phase 230V, but can monitor the whole house consumption perfectly.

#3

Iammeter should do it too Three Phase Energy Meter Wi-Fi,split phase,residential energy consumption,solar pv monitor,net energy metering, Modbus TCP/RTU I use these

#4

Interesting! I actually asked Shelly but their response was that it was not possible since the device needs a neutral line from the load it tracks, and it does not support neutral from a 400v load.

Have you tried?

#5

Ty! Looks interesting

#6

That’s a bit confusing. Monitoring 3 phase systems is exactly what the 3EM is made for. Since it’s measuring currents through a clamp, I don’t see why it would need N from a load. There is no physical reason for that. Though it should measure the currents of a 3 phase 400 V symmetric load just fine. I guess it is a symmetric load, because otherwise there’d be an N.
Further: If the heater is really symmetric, without an N connection, you could also measure just one phase, both other phases have to have the same load.

#7

Thanks for that!

#8

Did you find a solution for your 3x400v consumption tracking ? I’m in the same situation and would like to know if Shelly 3em can do it.
Thanks

#9

There may be differents power grids around the world.
However, I can confirm that Shelly 3em will work with the typical European grid which is
3 phase 230/400V + N at 50 Hz

#10

I contacted Shelly, and they told me that the 3em would NOT work with 400v. It will with 3 phase 230V, but not 400V. I did not try it myself but took their word for it.

I ended up using this one instead. It is rated specifically for 400v, and I can confirm it is working very well (incl local control via HA).

1 Like
#11

I guess that was some kind of missunderstandig.

When you have 3 phases and N, you can get 230V and 400V at the same time and that will work with the 3em. If you have only the 3 phases without N, you have 400V only and that will not work.

EDIT: Again: thats for the european grid, somewhere else it might work differently.

EDIT 2:

L1 - L2 -> 400V
L2 - L3 -> 400V
L1 - L3 -> 400V
L1 - N  -> 230V
L2 - N  -> 230V
L3 - N  -> 230V