lack of a cpc in part of a lighting circuit?

[brman]

It is the end of the week and my brain is failing so I am hoping someone can clarify this for me.

On a periodic I found the hallway lights (two lights, two way switching) has a cpc connecting the switches and lights but it doesn't connect to the rest of the circuit. The rest of the circuit checks out fine. Lights are class 2 and switches are plastic. However the switch back boxes are metal and screws can be touched.

I initially thought a C3 as they are class 2 fittings but then thought maybe a C2 as the screws give access to the metal back box. I am sure I read something about this somewhere recently but can't find it.

Anyone care to put me right?

 

[Sintra]

Nylon 3.5mm screws are available for the switchplates along with 30mA RCD's or RCBO's

 

[Edward Amsden]

Seems more serious than this, (or not???) anyone explain?

 

[Edd]

It is the end of the week and my brain is failing so I am hoping someone can clarify this for me.

On a periodic I found the hallway lights (two lights, two way switching) has a cpc connecting the switches and lights but it doesn't connect to the rest of the circuit. The rest of the circuit checks out fine. Lights are class 2 and switches are plastic. However the switch back boxes are metal and screws can be touched.

I initially thought a C3 as they are class 2 fittings but then thought maybe a C2 as the screws give access to the metal back box. I am sure I read something about this somewhere recently but can't find it.

Anyone care to put me right?

the way im reading this is that part of the circuit has a cpc, but dosent go anywhere as the rest of the circuit doesnt contain an earth, or is the switches your talking about with a cpc go back to an earth?
If the cpc's are conected but dont go back to a reliable earth source then they should not be connected together as a fault on one part will liven up the other cpc's.. hmmm hope that makes some sort of sence... If all class 2 and nylon screws used then no earth requierd so c3 if an earth wire is pressent and indicated as an earth but is not earthed then c2 as this could become live in a fault situation...

 

[brman]

Nylon 3.5mm screws are available for the switchplates along with 30mA RCD's or RCBO's

Thanks, but it it not so much the fix that interests me (I strongly suspect if I dig in the ceiling I will find a cpc that can be connected) but what is the correct coding on a EICR?

 

[telectrix]

code c3 if no cpc installed at all, but code c2 if it;s there but not continuous/faulty.

 

[brman]

the way im reading this is that part of the circuit has a cpc, but dosent go anywhere as the rest of the circuit doesnt contain an earth, or is the switches your talking about with a cpc go back to an earth?
If the cpc's are conected but dont go back to a reliable earth source then they should not be connected together as a fault on one part will liven up the other cpc's.. hmmm hope that makes some sort of sence... If all class 2 and nylon screws used then no earth requierd so c3 if an earth wire is pressent and indicated as an earth but is not earthed then c2 as this could become live in a fault situation...

Makes sense.
The lighting circuit overall has a connected cpc. This section also has a cpc that connects the switches but it does not connect to the rest of the circuit and hence doesn't connect back to the MET. So yes, a fault to the cpc anywhere on this section would not cause ADS but will make the switch back boxes and screws live.

So a C2 as it stands but a C3 if the screws were changed to nylon as they are the only exposed conductive part?

 

[brman]

code c3 if no cpc installed at all, but code c2 if it;s there but not continuous/faulty.

Thanks. Would you still say C2 if they were nylon screws (ie. no exposed conductive parts) or would you agree that goes to a C3?

 

[telectrix]

nope. code C2. changing screws to nylon would not rectify the fault. you could still get a fault to back boxes, even though technically not exposed, they are still classed as an exposed conductive part.

 

[Edd]

nope. code C2. changing screws to nylon would not rectify the fault. you could still get a fault to back boxes, even though technically not exposed, they are still classed as an exposed conductive part.

yep as telectrix says,, if the cpc's do go back to earth then no problems, but if not then in a fault condition the non earthed cpcs will become live and so will the back boxes, so C2 if the earths are indicared as earths and conected together...

 

[brman]

Ok, thanks guys. I am pretty sure the owner is happy to spend the time on a proper fix so the cpcs will be reconnected.