Micro Current Transformers

[denes44]

Hello!
I just want to make sure if these small closed clamps can be used as well?
The specification looks okay, the only difference between the SCT-013 is the lack of the TVS protection diode.

I have very limited space in my electrical cabinet, so these would fit more nicely.

[CircuitSetup]

I wouldn't use something without, at least, a protection diode built in. You rub the risk of open circuiting, which could lead to a hazard pretty quickly under the right conditions.

We sell the sct-006, which is clamp on (you wouldn't have to remove wires from the breaker to install them) and have the protection diode. They also come with the 3.5mm jack.

[denes44]

And what would be the risk of the open circuit, other than that I have to treat the wires as live?
The SCT clamps also states that they should not operate in an open circuit:

I am planning to design my own version as a DIN rail mount, and install everything inside the cabinet, so I don't mind treating the cables of the clamps live. And I don't need the 3.5mm jack because of this.

The SCT-006 is still much bigger then this version. I can still install my own TVS diode either to the PCB or the cable itself.

[denes44]

Okay, regarding the issues with an open CT I found an answer:
https://docs.openenergymonitor.org/electricity-monitoring/ct-sensors/installation.html

If an unburdened CT (i.e. one without a burden resistor) is attached to a current-carrying conductor, the CT will generate an unsafe voltage at its leads which could break down the insulation and destroy the C.T.

Always connect the C.T. leads before clipping it round a current-carrying conductor, and always un-clip the C.T. from the current-carrying conductor before disconnecting its leads.

Never open-circuit a C.T. whilst it is on a current-carrying conductor.

[denes44]

Another source about what could happen during az open circuit:
https://community.openenergymonitor.org/t/has-anyone-tried-the-sct023r-ct-from-yhdc/2894/38

Without a burden, all the primary current is magnetising current and the core will be completely saturated except for a very short period at the zero crossings. There, the rate of change of flux is so great that voltages of several kV can be generated, and (usually) the insulation flashes over, destroying the c.t. There is obvious danger if this happens and anyone is too close.

[denes44]

What I can't get my head around is the datasheet.
For the 2000/1 ratio, it says, that the Rated current is 5A, but the measuring current is 0-24A.

So what is limit actually for these?