Insulation resistance testing

Hi guys 

i was carrying out a insulation resistance test on a board today, the board is full of rcbo.

the company wanted me to carry out a erroneous connection test.when I did it I kept getting a low reading, the rcbo have a functional Earth on them .when I carried out a overall insulation resistance test between conductors and earth I got 2.43m ohms 

why would this be happening is it because of the coil in the rcbo??????

RCBO's shouldnt be IR tested, the outgoing circuit should have been disconnected

Contactum?