I'm planning a residential 3-phase ESS install using 3 x 5kva Multiplus II.
Looking at the meter requirements I purchased a EM530 assuming I needed to use CTs given I have a 3x100A supply (EM540 is max 65A). But, now I've looked at my expected max current I'm only going to have a max of 50-55A on any given phase, even with two 11kW car chargers and all appliances on the go.
So, the question is: Should I use the EM530 I have, but select a 60A CT, or is it really best to send back the EM530 and get the EM540?
Aside from the fact that the installation of the EM540 is simpler, the only difference seems to be "active power" accuracy and minimum current.
EM530 (assuming 5:60 CT):
- Accuracy: 0.5% (>3A), 1% (0.6-3A) (+ 0.5% from CTs so 1-1.5% overall?)
- Min current 0.6A
EM540:
- Accuracy: 1% (>1A), 1.5% (0.5-1A)
- Min current: 0.25A
Looks like it's probably a good idea to switch to EM540 given this. Make sense or am I interpreting things incorrectly? Any thoughts?