Outside lighting

[jamie-spark]

looking for a bit of info

went to look at a job today sorting outside lighting, the cut out is a mess. The swa are not terminated using glands and instead earth clamps round the exposed armouring. It is a tnc-s supply and am sure i have seen it some where that the end light should have a rod connected to it, although i can not find this in the regs. What i did find that reg 559.10.3.4 requirea a mimimum copper equivilent conductor not less than 6mm. It only has a 2.5mm2 3 core and the swa works out at about 2.4mm2 something copper equivilent conductor.

Any ideas cheers:rolleyes4:

 

[telectrix]

if the L and N conductors are 2.5mm, then the cpc need not be more than 2.5mm. IMO. the terminations need sorting though with proper glands.

 

[jamie-spark]

if the L and N conductors are 2.5mm, then the cpc need not be more than 2.5mm. IMO. the terminations need sorting though with proper glands.

cheers telectrix but does reg 559.10.3.4 not state minimum earthing size is 6mm

 

[Engineer54]

Can you give a little more information about the type of outside lighting your talking about please??

 

[spark 68]

559.10.3.4 : The Earthing conductor of a street electrical fixture shall have a minimum copper equivalent CSA of not less than the supply N conductor at that point or 6mm^ whichever is the smaller

 

[jase]

cheers telectrix but does reg 559.10.3.4 not state minimum earthing size is 6mm

no it says it shall have an earth not smaller than the neutral or not less than 6mm whichever is the smaller, in this case that would be 2.5mm

 

[jase]

when you say the cutout is a mess is is a proper street lighting cutout? these sometimes just have a brass cone on which the armoured goes over and indeed is clamped on with a pipeclamp type band
Street Lighting Cut-Outs

 

[telectrix]

jase beat me to it, while i was making a sarcastic comment on another thread. as i said in post #2, same size as L/N conductors is compliant. the 6mm comes in where the L/N conductors are >6mm

 

[Engineer54]

What i'm thinking about, is if these are pole mounted lighting units, then the metal poles may well be extraneous, being set in the ground in a concrete base, and could well need a bonding conductor linking these posts out on a PME supply...

 

[jamie-spark]

cheers guys

it is small private lamposts in a car park with 2 x 70w sons. They are not glanded of and not restrained ( only thing that is holding them in place are the terminations). originaly went to change lamps and noticed it when pulling out the cut out fuse

 

[jamie-spark]

What i'm thinking about, is if these are pole mounted lighting units, then the metal poles may well be extraneous, being set in the ground in a concrete base, and could well need a bonding conductor linking these posts out on a PME supply...

was thinking along the same lines. I know i have seen a bit about a rod at the end one. Not sure if its in GN8 which i dont have at hand right now. Hench why i asked you kind fellows

 

[jamie-spark]

when you say the cutout is a mess is is a proper street lighting cutout? these sometimes just have a brass cone on which the armoured goes over and indeed is clamped on with a pipeclamp type band
Street Lighting Cut-Outs

no mate just a 20mm hole

 

[Engineer54]

was thinking along the same lines. I know i have seen a bit about a rod at the end one. Not sure if its in GN8 which i dont have at hand right now. Hench why i asked you kind fellows

Then i would first test these poles, (you haven't confirmed or otherwise if these are pole mounted lighting?) to find out if they are extraneous or not. If they, are it would be far easier to TT these poles than to provide a bonding cable!!

EDIT ...sorry i missed the post where you confirmed they were posts ...lol!!

 

[Engineer54]

was thinking along the same lines. I know i have seen a bit about a rod at the end one. Not sure if its in GN8 which i dont have at hand right now. Hench why i asked you kind fellows

It doesn't matter too much where the TT rod is installed, so long as all the posts are connected via the SWA from the post position where the Rod is connected too!! Don't forget to isolate the incoming supply SWA, as that will still be at the house PME potential...

 

[spark 68]

There does not seem to be anything specific for street furniture in the regs.

5 second disconnection time for the distribution circuit (TT or TN)

Should be RCD'd (locally)

Only (the frame etc.) needs earthing if non-sheathed cables are used or class 1 fittings are used.

having said that I only have the 'old' GN8, as I haven't got the new revised copy

 

[jamie-spark]

dont think it is out till april. Where does it state should be rcd protected.

cheers

 

[spark 68]

dont think it is out till april. Where does it state should be rcd protected

In GN8 (page 141).

The RCD is shown in the actual switchgear/control gear for each individual item (Lamp standard or whatever).

 

[Engineer54]

There does not seem to be anything specific for street furniture in the regs.

5 second disconnection time for the distribution circuit (TT or TN)

Should be RCD'd (locally)

Only (the frame etc.) needs earthing if non-sheathed cables are used or class 1 fittings are used.

having said that I only have the 'old' GN8, as I haven't got the new revised copy

This is basically garden lighting fed from a ''domestic supply''. I don't think the section your referring too applies in this instance!! Though i may be wrong!! ..lol!!

 

[jamie-spark]

:rolleyes4:

thanks i think

 

[spark 68]

Hi E54,

it comes under the heading 'highway supplies' , as far as I read it, it does not really point to any difference as whether this is private or public.

It also points to section 4.12 in GN5, where it mentions the 'anomaly' re: disconnection times up to the switchgear in each item.