Afternoon all. I’m doing a dorma / loft extension all circuits for that extension are new . I’m going to upgrade the consumer unit also to rcbo/spd. Now I took a switch off yesterday on the existing lighting circuit and noticed the twin and earth cable had a green goo inside the insulation when stripped back it wasn’t a lot I’ve seen worse . Now my question is if all the IR Readings are good is the cabling ok to be left and connected into new consumer unit . I will be doing an eicr on the existing circuits before changing the board so will get a better idea if it’s affected the insulation .