So what would happen if you did not have continuity back to the CU but did have an earth/CPC link between light fitting and switch?
Wiring For Light - Two Red Wires & Earth
- Thread starter pbar
- Start date
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If the earthconductor is not sound or is not connected to the earth at the consumer unit then this test method creates the risk of other "earthed" items becoming live.
Well, I tried this method and neither combination would make the test lamp light.
I sort of suspected this would be the case, as the earth had been cut back more so than the other two wires, the previous electrician had obviously decided to use this cable which he must have had to use up, to achieve what was required at the time.
I used a neon screwdriver in the end to determine which was the live.
I sort of suspected this would be the case, as the earth had been cut back more so than the other two wires, the previous electrician had obviously decided to use this cable which he must have had to use up, to achieve what was required at the time.
I used a neon screwdriver in the end to determine which was the live.
pbar,
If your CPC (earth cable) has been cut back on your lighting circuit, non of the accessories (switch plates/light fittings) are metalic are they?
As this could be very dangerous.
If your CPC (earth cable) has been cut back on your lighting circuit, non of the accessories (switch plates/light fittings) are metalic are they?
As this could be very dangerous.
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P
PrinceofDarkness
At least the O/P now realises that he doesn't have an effective earth having used that temporary test lamp - which for the few seconds duration of that 'test' wouldn't have posed a significant risk to other accessories - and in any case would be limited by the resistance of the lamp......
Had the O/P used a neon screwdriver initially, to identify the hot wire, then he would'nt have known that his earth connection was unreliable.
We still don't know whether his fittings are Class I or not and it remains to be seen what he intends to do about this problem - if anything.
Lucia.[/i]
Had the O/P used a neon screwdriver initially, to identify the hot wire, then he would'nt have known that his earth connection was unreliable.
We still don't know whether his fittings are Class I or not and it remains to be seen what he intends to do about this problem - if anything.
Lucia.[/i]
P
PrinceofDarkness
So, all's well that ends well, then - and you've managed to answer your own question........
Lucia.
Lucia.
I guess I have yes, invaluable help here though, as usual, especially from you PrinceofDarkness, cheers.
As a matter of interest, what's the difference with double insulated light fittings, is it simply that the cable has extra insulation.
As a matter of interest, what's the difference with double insulated light fittings, is it simply that the cable has extra insulation.
Double Insulated
Double insulated or class 2 electrical appliances are products that have been designed in a way so as not to require a safety connection to electrical earth (These products must NOT have a safety connection to Earth).
These products are required to prevent any failure from resulting in dangerous voltage levels becoming exposed causing a shock etc. This must be done without the aid of an earthed metal casing. Ways of achieving this include double layers of insulating material or reinforced insulation protecting any live parts of the fitting.
There are also strict requirements relating to the maximum insulation resistance and leakage to any functional earth or signal connections of such appliances. Products of this type are required to be labelled "Class II", "double insulated" or bear the double insulation symbol (the symbol displayed above)
P
PrinceofDarkness
Widening this discussion, now that the O/P seems satisfied: Does anyone here agree that there are certain fittings designated as Class II when perhaps they ought to be Class I?
I have in mind particularly, those shoddy 'cheapo' 230V metallic downlights. OK, they have a suitably robust ClassI ceramic lampholder, but this is fixed to a steel base with two insulated - but unsheathed wires leading to the plastic terminal cover mounted on steel stirrup bracket held in place by one of the fixing springs.
The problem here, due to careless installation, is that those two wires are often stretched across the sharp edge of that stirrup in the full rising heat from those dreadful, wasteful 50W halogen lamps.
Regular installers of these beastly fittings will know just what I mean.
I couldn't give a fig for some MI's - particularly when they're written in Pidgin English......
Lucia.
I have in mind particularly, those shoddy 'cheapo' 230V metallic downlights. OK, they have a suitably robust ClassI ceramic lampholder, but this is fixed to a steel base with two insulated - but unsheathed wires leading to the plastic terminal cover mounted on steel stirrup bracket held in place by one of the fixing springs.
The problem here, due to careless installation, is that those two wires are often stretched across the sharp edge of that stirrup in the full rising heat from those dreadful, wasteful 50W halogen lamps.
Regular installers of these beastly fittings will know just what I mean.
I couldn't give a fig for some MI's - particularly when they're written in Pidgin English......
Lucia.
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