Thank you all for your kind suggestions:
The scope is powered through a isolation transformer- - no earth
The circuit is battery powered - no connection to mains or earth
All channels except CH4 are physically disconnected from scope.
CH4 connected to current transformer specs here
https://www.pearsonelectronics.com/pdf/4100.pdfCH4 set to DC
CH4 connected to CT via BNC to probe adapter
![SIGLENT SDS1104X-E measurement problems](https://www.eevblog.com/forum/index.php?action=dlattach;topic=239070.0;attach=978298;image)
CH4 connected to CT via 50ohm coax
![SIGLENT SDS1104X-E measurement problems](https://www.eevblog.com/forum/index.php?action=dlattach;topic=239070.0;attach=978302;image)
CH4 connected to CT via 50ohm coax with 50ohm termination
![SIGLENT SDS1104X-E measurement problems](https://www.eevblog.com/forum/index.php?action=dlattach;topic=239070.0;attach=978306;image)
Changing to 2V/DIV makes it impossible to trigger due to preceding noise, no matter what I set holdoff time to, it triggers at the same noise in the beginning.
It should be noted, that there are no problems when the scope is not only in 1V/DIV, but it's also fine at 500mV, 200mV etc. it's everything above 1V/DIV that presents problems.