The JIB use noted references to qualifications, if the quals earned are not within the remit then you will not get a JIB ecs card.
If the HSE come onto any site they will request that all cards show the work level that each employee is trained to work at. If your an electrician with just an CSCS card you will not be allowed to do any electrical work and removed from site.
I have had many electricians who have come for interviews who do not hold the correct cards for site work, many of them trained by training groups who promise the earth and deliver nothing.
I am not bias I will, if the urge takes me, give those who show promise a chance, however this is very far from present and past experience.