Shelly 3EM or 3EM Pro as 3 independent current/power measurements

  • It is possible to use any of the 3EM devices as independent current/power measurement channels connected to the same phase?

    As long as the voltage phase matches the current clamp. Of course power factor and composed measures render useless.

    for example 1:

    channel1 --> R --> voltage to R --> current clamp on desired load.

    channel2 --> R --> voltage to R --> current clamp on desired load.

    channel3 --> T --> voltage to T --> current clamp on desired load.

    +N

    for example 2:

    Voltage connected to R, S, T

    channel1 --> R --> current clamp on desired load --> Software assigned to R

    channel2 --> R --> current clamp on desired load --> Software assigned to R

    channel3 --> T --> current clamp on desired load --> Software assigned to T

    +N


    Ideally I would like to associate a current clamp to a certain channel and keep the voltage inputs as regular 3-phase. If not, can I connect each voltage channel to the desired current measure?

  • Example 1 should work as intended. The manual shows that 1 phase energy and power measurement is possible for max. three consumer devices or circuits. Even the power factor at each circuit will be correct.

    Don’t understand example 2: You’re planning to install the pro 3EM at three phases, but the current clamps at two phases only? This will render false readings for power and energy (and power factor). Could you please explain?

    „Habt Geduld. Alle Dinge sind schwierig, bevor sie einfach werden!“ (aus Frankreich)

    „Nothing in life is to be feared, it is only to be understood.“ (Marie Curie, 1867-1934)

    „Comment is free, but facts are sacred“ (C.P. Scott, britischer Verleger)

  • I've got a 3-phase installation.

    I want to check several consumptions split over several phases, to check individual consumptions. I would like to use it as three independent channels until I have my loads characterized.

    IExample 1 works, It means I could use 3 R loads, or 2S and 1T loads, or any other combination. Setting up voltage input for the specific load you want. In this case if your clamp changes the phase you have to change the voltage input as well.

    Example 2 means, you set up voltages sensors and then by software you assign every current clamp to the phase you want as monophasic load. In this case you dont need to change voltage inputs once set up.

    Where I can find the manual, mine came with small instruction papper and the same schematic you can find on the side of the device.

    Can you refer me to the full manual of the product?

  • There is no way to assign the current clamps to specific voltage measuring points. Please have a look at the technical documentation:

    https://kb.shelly.cloud/knowledge-base/shelly-pro-3em

    „Habt Geduld. Alle Dinge sind schwierig, bevor sie einfach werden!“ (aus Frankreich)

    „Nothing in life is to be feared, it is only to be understood.“ (Marie Curie, 1867-1934)

    „Comment is free, but facts are sacred“ (C.P. Scott, britischer Verleger)