Do you really mean that? Are you looking at the Solar Panel side of the inverter, because that’s where the d.c. is with positive and negative wires, and you must not touch that for two reasons - (1) they’re always live until it goes dark outside, and (2) no current transformer - nor any transformer - works on d.c.
If you’re looking at the supply side of the inverter, the wires are line and neutral, and they are probably in a 3-core cable along with a protective earth conductor.
I would look at inserting a c.t. in one of two ways:
1. If it’s easy and there’s room, put the c.t. either inside the inverter or inside the consumer unit. I doubt that there’s room inside the isolator.
2. Cut the cable and put the two ends into a plastic box (using the correct grommets etc for the cable entry, inside put a screw terminal block to join the two neutrals and the two earths, take the two line conductors into separate terminals and link them with a loop of wire passing through the c.t. Obviously, the loop has to be the same capacity as the conductors you cut.
Either way, you maintain the integrity of the wiring and there are no wires exposed without mechanical protection against damage to the insulation. (Remember, the insulation is the blue or brown plastic, the outer sheath is not insulation, it’s mechanical protection.)