Extra Low Voltage Downlights (help)

[ianphilip007]

hello there

have a possible job lined up to fit 4 elv(12v) downlights in a smallish room, now the room is not classed as a special location so as i understand it a pelv or selv circuit could be used. i have not previously fitted elv downlights so not really sure about whats available or what i would need.

1/ i see that there are pre wired selv transformers, and non pre wired transformers. Am i correct in thinking that the non pre wired can be con figured for a pelv circuit?

2/ for a pelv circuit do the actual downlight fittings have to be double insulated?therefore different to selv fittings

3/ is the supply side of the transormer (selv) earthed? as the seperation is provided by the double insulation between primary/secondary. fully aware that the ELV side has no direct connection to earth.

4/ which configuration is used for non special locations pelv or selv circuits

i know some of these questions are basic just never worked on elv up until now, any advice much appreciated.

 

[telectrix]

basically, the transformers are classII so all you would do would be to supply each transformer with 1.0mm or 1.5mm T/E,.switched live and neutral , leaving the cpc terminated in a block. then i would wire from each TX to it's elv fitting in 1.5mm heat resistant flex ( unless the TX's come with leads ). as it's not a special location, no need to notify, just fill in a Minor Works. bear in mind that each downlight draws 4 and a bit amps at 12v, so ensure the connections are sound.

 

[ianphilip007]

thanks telextrix, so no earth to transformer at all just leave it terminated in the wagobox, i assume this is for a selv circuit? is pelv not realy used??

 

[ianphilip007]

you say each fitting draws 4amps (4x4 = 16a), thats on the elv side so wil not affect the lv side 6amp mcb protection lighting circuit correct ??

 

[telectrix]

pelv is not used here, just selv.

 

[ianphilip007]

grt thanks teletrix

 

[telectrix]

current draw is no problem on the "mains" side. say 20 A @ 12v is only 1A @ 240v

 

[Deleted member 9648]

you say each fitting draws 4amps (4x4 = 16a), thats on the elv side so wil not affect the lv side 6amp mcb protection lighting circuit correct ??

The load on the lv side will be the total load in watts/230v as with any other circuit.