Line splitters, this is one inexpensive but a very useful tool.
But if you have higher expectations as is using them with an oscilloscope and a relative current probe, you need to be aware all times, which side is Line and which one is Neutral.
Because at AC load testing, you also expect your differential voltage probe this to be in phase with the current probe.
The new target this is voltage along current curve, both to be at zero phase shift with a resistive load.
Exactly as is presented in electrical theory.
At DC power we use the words as polarity inspection, at AC power when this is to be reviewed and measured by one Oscilloscope, we are now obligated us perform phase-shift inspection instead.
At one workshop the map of what is Line this starts from the wall plug (source), if there is any VARIAC in the way, then it output socket this should be mapped too.
At my lab I have also one active AC voltage stabilizer (voltage source), this now it should also be mapped.
Last in the chain this is my humble line splitter.
All line splitters with identical exterior design with DE-10ALS they are easy to open and its easy to review it internals.
In most of them any wires color code this does not translate to anything.
Neutral and GND wires they are equal to jumper connections, and the factory uses whatever cable color they do have in stock.
I did read recently a German article in which the technician was wonder of what is best wire routing for the GND?
Speaking of wiring correctness, only if you decide to use this splitter with Line wire as mapped, then you should bother of the rest details too.
In my case I did complete mapping of my electrical sources, and then I did select GND wire to be routed along neutral (within the splitter housing).
But this is not enough, as I was had to add more visual indicators which these will remind me of where is the right spot to clamp on the probe (always in Line wire), no matter if the splitter this is reversed or not.
You are not obligated to follow my path of actions, if what you have this is a regular clamp-on meter.
Now for the hunters of correctness (AC/DC current probe for Oscilloscope), I did take some photographs for a better illustration of my workaround.