Solis: CT Model or Meter Model (how to determine which one I have?)

Good Day,

I purchased a Solis-1P3K-4G (grid-tie inverter).

The latest Manual (Ver 2.7), page 20 makes mention of the following:

“Inverters are classified as “Meter Model” and “CT Model” due to hardware difference. Meter model can only connect a smart meter. CT Model can only connect a smart sensor. Please consult Solis Sales Rep before placing order.”

I would like to know how I determine which one my Inverter is as I am planning to get a CT for it but now unsure if a CT will work if it is perhaps a “Meter Model”, but not sure how to determine that.

Thank you,

You can use a 100/33ma for that inverter.

Hi Johan,

Thank you for the reply, so I take it I have the “CT” model?

This seems to be the CT for it then: Solis Current Transformer 100A 10m (100A / 33.3mA / 10 Meter cable). My inverter will be more than 10 meter away from the main DB Board, I saw on a previous test one can use a longer cable (exceed 10 meter) as it is a signal cable only and won’t really carry any significant current. So does one just “snip” it somewhere and patch in an additional piece of wire to extend it? Does not seem like one get longer ones standard, so probably have to extend it yourself if required?



I cut and extend, normally with twisted pair, screened milar cable. Longest were about 35 meter.

CTs are current sources, so in theory the wire length doesn’t matter. In practice, it means that the burden resistance on the CT increases as you increase the wire length, which should be negligible, but CTs do have a power limit and if the resistance is too high you could exceed the power limit of the CT. I doubt you would have that problem with a CT that only has a 33mA output though.

For those that do not know what a CT (Current Transformer) is, you can get more information here.

It is a type of transformer that produce electricity by electro magnatism.
If you think of those light bulbs that you see on the powerlines that shine at night to warn pilots of the line’s location, this is how they are powered.

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Thank you very much for the info.

So with a CT installed one should theoretically be able to disable any power coming from the Inverter going back into the Eskom power grid, but there would probably be a negligible (small) amount for synchronization or when there’s a bit of lag between the CT and Inverter having to react to current signal from the CT where it might push a bit of power back into the grid but won’t cause damage to a Prepaid Smart Meter?

Normal Smart meters will detect the reverse flow and bill you accordingly. Is typically a few cents a day. Conlog and Ecolec will trip, conlog can be programed not to… Ecolec needs replacement.

With 90% of other brands you should be fine. To damage a prepaid needs a lot more than the inverter you plan to use.

Thank you Jaco.

Smart Meters are to be rolled out in our area between May and July, so probably better I first see what they install before spending a lot of Money on Solar Panels, CT etc. which I might not be able to use in the end. * EDIT * I found a picture on our street WhatsApp group, seems like they will be installing Conlog by the looks of it. One owner posted a picture of their meter when they struggled to load credit after installation. So in such a case one needs to request the installer (contractor) to set it not to trip if one make use of a grid-tie inverter?