lightlng circuits in old houses with no earth

[r.b]

Hello i have got a question about old house wiring its at my nannas and sisters houses on the downstairs and upstairs lights.They have no earth cable within the pvc at all ,my gut reaction was this is a code the lights will need rewiring.I am on with my nannas at the moment, i cant remember which post i read on the forum . It was about not requiring an earth on lighting circuits but all the back boxes ,light fittings have to be plastic no metal used and as long as they are rcd protected its passable is this even correct ?.All i need to know is does the lighting need rewiring ?Im doing the upstairs lights new at a later date, i have got a feed and neutraul to a loft light switch at the moment at my Nannas anyway help appreciated

 

[Sharpend]

Have you heard the terms 'class1' & 'class2'? Not including at school! 

You may wish to refer to the regs to gain a better understanding. 

 

[Murdoch]

What do you mean by "within the pvc"?

 

[NozSpark]

All I read there was ... blah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blah.......

A lot of correct punctuation would be a great help for those who you want answers off,,,,

but the upshot is.... no class 1 accessories, a label to say not to fit class 1 accessories,,,,, and then I like to RCD it (but some on here say that it's not necessary)

 

[Doc Hudson]

As there is no Zs path then clearly it is not going to meet maximum permissible earth loop impedance values for fault protection as per 411 to achieve ADS. Also 531.2.5 suggests that RCD's carry negligible fault protection in circuits with no CPC where a CPC is normally expected to be included. So unless you can prove that the whole circuit is effectively double insulated, (All ClassII accessories),  then the only other solution is to rewire or include a CPC to all accessories.

Doc H.

 

[r.b]

Class 2 does not require an earth i guess 

 

[Doc Hudson]

Have a look at the definitions in section 2, Class I, II & III are all described toward the top of page 25. Basically Class II accessories or appliances have no exposed conductive parts. So a CPC connection carries no function whatsoever. A lot of garden power tools, lawn mowers, hedge trimmers etc, are Class II.  All plastic external parts and their leads do not include an earth, CPC conductor. A traditional ceiling rose and pendant is a Class II accessory, where the earth CPC connection is only there to terminate and continue the earth continuity to the next accessory in the circuit.

Doc H.