Carlo Gavazzi ET340 and External transfer switch

Q&A and troubleshooting
, , ,
1

Good day.

I am connecting 2 x Multiplus ii 8kVa inverters in parallel. I have read and understood the instructions on the external transfer switch

One thing I’d like clarity on

  1. The house has 3 phase supply, and the 2 multiplus inverters are on one phase
  2. There are other loads on the other 2 phases that also need to be measured
  3. I understand I’m using the Current transformer to measure power usage on the phase with the inverters

Question is: How do I measure usage for the whole 3 phases? Can I use a Carlo Gavazzi ET340 as well as the CT in the same installation?

Thank you

2

You don’t need the ct’s if you use an EM.
Frankly, CT’s with parallel systems aren’t great, the EM is the better solution.

3

Are you sure?!

As far as I know, with an external transfer switch you need the CT’s for safety as is drawn in the diagrams. When the TS is switched off and the MP-II measures any current, it will switch off the system to prevent accidental back-feeding in the case of grid loss. I can not use the EM/ET here, as it is not certified for that.

The EM/ET is solely for ESS use. You’ll need them both in the case of an external transfer switch.

4

Sorry, yes, it is a requirement for the ETS solution, I forgot about that part, it is hardcoded into the software.
You don’t get more accurate than an EM but it sounds like its more about response time of measurement.