Two PIRs two transformers and no lights

[Junctionbox]

I have a 12 volt induction type transformer supplying halogen step lights turned on by a PIR movement detector at the front door. It works fine. But when I tried to put in an additional PIR near the drive to supply the same lights via an additional induction transformer things went wrong. When either PIR operates on its own, fine. But the minute a second one operates everything goes off. Cancel either of the PIRs and it works again. Is it because two transformers shouldn't supply the same source? Is there a remedy?

 

[Taylortwocities]

Could it be that the new PIR can see the lights and thinks that it is daylight?

Turn the lux setting on the PIRs to daylight(test) mode and see if it works OK then.

 

[winston1]

I have a 12 volt induction type transformer supplying halogen step lights turned on by a PIR movement detector at the front door. It works fine. But when I tried to put in an additional PIR near the drive to supply the same lights via an additional induction transformer things went wrong. When either PIR operates on its own, fine. But the minute a second one operates everything goes off. Cancel either of the PIRs and it works again. Is it because two transformers shouldn't supply the same source? Is there a remedy?

As you suggest you can't parallel the outputs of the transformers. If they are real transformers they may work if wired in phase but there could be circulating currents. If out of phase I would expect a big bang from the MCB. If they are actually electronic switch mode power supplies paralleling them would not be a good idea though I imagine the electronic safety trip would operate.

The remedy depends on the PIRs. If they are relay types you can parallel both PIRs into a single transformer. If they are totally electronic you can't.