Is it enough to prove safe isolation on a circuit which is controlled by a PIR on a seperate circuit ? Electrical Advice

Is it enough to prove safe isolation on a circuit which is controlled by a PIR on a seperate circuit ? Discussion ThreadIs it enough to prove safe isolation on a circuit which is controlled by a PIR on a seperate circuit ? Electrical Advice

Hi Guys currently doing my apprenticeship and looking for some external advice regarding safe isolation.
Situation is a circuit supplying some external street bollard lights and 1 or 2 street lamps. This circuit is fed via a single phase MCB then through a contactor all located in the db. The contactor is pulled in when a PIR sees it’s dark outside. This PIR on a seperate control circuit to energise the contactor coil.
Question is, is it enough to prove safe Isolation just on the circuit supplying the loads ? Or Should safe Isolation also be completed on the seperate control circuit aswell ?
Any help would be much appreciated and you have any references in BS7671 or relevant material that would be fantastic,

thanks guys

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