Wiring PIR lights s...
 

Wiring PIR lights so they wont trip the main RCD if their power is disconnected

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So after speaking to a some neighbours it seems a few garages around my area have been broken into lately and the thief's are ripping off the PIR lights which then trips the RCD in the garage so all the CCTV cameras power off and a couple of neighbours who have mains powered alarms (with no battery back up) are also disabled

 

My security is very good but i like to remove any weakness that i can find so id like to wire up my PIR light so if its ripped off the wall it wont trip the main RCD in the garage (no option to mount the PIR any higher so it would be out of reach) battery powered PIR lights are a no go due to them being constantly activated by cats, foxes etc….

 

I was thinking could i fit a plug to the PIR wire then plug it into an RCD breaker plug and then plug that into the mains socket?  

 

Any other options that would work? did think about some kind of protection cage but they could be ripped off the wall also or cut open or the wire cut with some thin wire cutters 

 

 

 


 
Posted : 17/03/2026 9:15 am
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surely it would be safer and more failsafe to take power for the cameras from somewhere else? 


 
Posted : 17/03/2026 9:22 am
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You need a new garage CU that has individual rcbos, that way if they trip the lighting circuit all of the others remain working. The cameras and other security would have to be on a separate circuit to the lights though.

Whatever happened to that idea where somebody built a trip-based contraption that would set off shotgun cartridges in very close proximity to the culprits? Or fogging systems? Or flogging, come to that...


 
Posted : 17/03/2026 9:28 am
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How is your consumer unit set up? Mine only has sockets in the RCD, not lights so wouldn't have that issue.

You could wire a dedicated circuit, or get a ups for the CCTV 


 
Posted : 17/03/2026 9:29 am
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The RCD just has 3 switches, the main power switch then one for the lighting circuit and one for the plug socket circuit

This was all installed before i moved in and hasn't had any issues, just want a quick & simple way of making sure the whole RCD doesn't trip if the lighting circuit is attacked via the PIR 


 
Posted : 17/03/2026 9:56 am
 JAG
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I'd try putting the PIR Light on a dedicated RCD in the main consumer unit - my thinking is that then it will only trip the dedicated RCD and the rest of the house will remain active.

HOWEVER: I am not an Electrician 😆 


 
Posted : 17/03/2026 10:17 am
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Posted by: escrs

The RCD just has 3 switches, the main power switch then one for the lighting circuit and one for the plug socket circuit

This was all installed before i moved in and hasn't had any issues, just want a quick & simple way of making sure the whole RCD doesn't trip if the lighting circuit is attacked via the PIR 

EDIT do you mean, "The RCD just has 3 switches..." or do you mean, "The garage consumer unit just has 3 switches...?"

The garage supply possibly comes from the house and is on the RCD there.

If so there probably isn't a quick and simple way to do what you want apart from removing the mains PIR/light. CCTV is pointless if you're dealing with a hoodie youth wearing a surgical mask

Either replace the mains light with a solar/battery version and turn the activated time down low (I did see your fox/cats comment) which at least maintains the illusion of security or invest in a battery-powered alarm, like the Yale

 


 
Posted : 17/03/2026 10:26 am
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Sounds like a standard garage cu setup, RCD main switch and 2 breakers.

So swap the RCD for a basic 2 pole main switch, and the breakers for RCBO (RCD plus overload, i.e. the over current function that the MCB did). 

These days everything needs to be the same brand, i.e. replace wylex with wylex, mk with mk as appropriate. Also, double pole (breaks neutral as well as live) RCBO in a single module width are preferred and safer.


 
Posted : 17/03/2026 10:45 am
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So just gone to check everything and its not an RCD in the garage it a RCCB

The garage's power cable is buried under the lawn and looks to be connected to the conservatory’s power circuit, it looks to run to a orange power switch

 


 
Posted : 17/03/2026 10:54 am
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Oh. Messy then. The RCD that trips, is in the house or garage?

Maybe a UPS for the cameras is the easiest quick fix.

There was another thread recently someone looking for a loss of power alarm, that might help scare any miscreants away.


 
Posted : 17/03/2026 11:08 am
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RCCB is essentially a form of RCD

If they are attacking similar properties then it's because they've identified a weakness, i.e. an MO.

An RCCB does the job, but it's typically older and "budget-suitable" for a housing estate


 
Posted : 17/03/2026 11:21 am
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How about installing a UPS power supply to keep the cameras running if the power is tripped.  They usually have an alarm on them.  I'd be thinking about trying to wire a hidden alarm sounder into that and maybe some secondary lights.  (actually, don't most alarm sounders go off if the power is cut to them anyway? 

So that ripping the obvious light up sets off an alarm, a load of other lights and keeps the cameras running!

 

 


 
Posted : 17/03/2026 11:24 am
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Fit a Tapo solar powered camera as a backup to your wired camera? They could disconnect the solar panel but it would take weeks to discharge the battery in the camera itself.

 

Edit: you don't even need a solar one if you've got power in the garage, just get the one without the solar and leave it plugged in via USB so it's constantly charging. If the power goes out the camera still works.


 
Posted : 17/03/2026 11:34 am
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You could fit security cages over the lights


 
Posted : 17/03/2026 12:35 pm
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Posted by: markspark

You could fit security cages over the lights

 

This. Metal cages over the lights that were 'accidentally' connected to the live powering the lights themselves.....

 


 
Posted : 17/03/2026 1:06 pm
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My understanding is that the MCB protecting your lighting circuit trips if too much current is drawn, whereas the overall RCD trips if there's a short circuit to earth, and knocks the whole box off.  An RCBO should trip only the circuit with the faulty device and prevents the whole house going dark.  That might be your answer.


 
Posted : 17/03/2026 1:35 pm
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Also any rcd/rcbo will be pointless in the garage if the circuit supplying it has one fitted in the house as that one will trip first in an earth fault condition 


 
Posted : 17/03/2026 6:21 pm