Electrical panel monitoring
Your ambitions exceed your abilities... and there's a lot of problem scope you haven't really thought through.  

Don't reinvent the wheel

First, really, seriously scour the market for existing consumer products which might provide an API.  I'm seeing good signs that several consumer home power monitors can provide raw data streams.  For instance neurio said in 2016 they were expecting to have this data.  Sense has it in beta.   It's around; look harder. 

Also look into talking to your smart meter directly, which has the CT's in place. Some smart meters use Zigbee Smart Energy protocol.  

Research the literature on the subject

If you can't find any datastream access, then research what's already been  done in the field.  I see plenty of halfway respectable efforts. 

Use items that are actually UL-listed (CSA-listed, ETL, ЯU etc.)

CE is not a testing lab, it's the standard mark China puts on everything that will never see the inside of a testing lab because it's junk.  It's a fake of a European self-certification standard, but without the actual self-cert.  Everything you see on AliExpress, eBay or Amazon Marketplace will be rubbish from Alibaba. 

For instance, Magnelab makes CTs with either ЯU or UL listing (component vs. product suitable for direct use). 

Don't exit the panel with electrical wires of any kind

Any electronic equipment that lives inside the panel, stays in Vegas.  You cannot have any wire between your homebrew stuff inside the panel and the outside world.  The only possible communication scheme is wireless; and that's what all consumer home energy monitors do - they stick a WiFi antenna out a knockout.   

That means you'll be doing Raspberry Pi and not Arduino. 

Or both - the way you get >6 analog inputs into an Arduino is to use two Arduinos.  They could be slaved to the Raspberry Pi. 

Absolutely no signal wires in or out of the panel.  

No running with your panel cover off - it's not a PC.  The panel cover has a vital safety function other than the obvious; it holds the breakers in.  Without it you can rock a breaker out by turning it off. 

One more thing: On simple circuits, put the CT's on the neutral wire. 

And lastly, no signal wires in or out of the panel.