Chauvin Arnoux MiniFlex MA110 Notice De Fonctionnement page 33

If you make long‑duration records, you must deactivate automatic power off (see § 2.2.6).
The insulation between the type B micro‑USB connector and the measurement output is 1000 V CAT III or
600 V CAT IV. That makes it possible to connect the device without risk to wattmeters having uninsulated
inputs. The type B micro‑USB connector must not be in contact with conductors or uninsulated parts at
dangerous voltages
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