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Posted By Topic: how to determin lighting points by Table C8

eletimpang
Jan 25 2016 01:19

hi guys
I m confused about determining lighting points by Table C8,according to Table C8 notes(f) which says :
A luminare is deemed to comprise one or more lighting points,according to the number of points at which it is connected by flexible cords to the installation wiring,or according to the number of sections in which it is switched or controlled.

the question is if I put 10 led downlights controlled by one switch in the family room,that would be deemed 10*o.5=5 points or just 1*0.5=0.5point?
what is the meaning for "according to the number of sections in which it is switched or controlled".in which conditions we can determin the lighting point according to the number of sections?
   

dbuckley
Jan 25 2016 09:25

Because your 10 LEDs are controlled by one switch, then the second part of the clause is invoked, its one switched section, so half a point.

Of course, Appendix C is informative, not nominative, and in particular, don't ignore what C5.1 says. You _can_ use table C8, but it is in no way mandatory, even in an informative sort of way. If common sense and judgement, as called out for by C5.1, gives an answer different to table C8, then that is OK.


   

AlecK
Jan 25 2016 09:40

Note f is there to cover large multi-lampholder luminaires.
A large chandelier with 20 lampholders is one point if there's only one connection to installation wiring.

If it had 2 sections within it that can be switched separately, then it becomes 2 lighting points.

more commonly, think of an HLF unit. It has one or two lamps for illumination, plus some that are switched separately for the heating function, plus a fan also switched separately; so can be 3 or 4 separately switched sections thus making it count as 3 or 4 "points".

See definition of "luminaire" [1.4.64].

10 x standard LV lampholders are 10 individually-connected luminaires, so they count as 10 points regardless of how they are switched.

10 X ELV downlights with individual transformers is the same: 10 individual connections to the circuit = 10 points.

Reconfigure to have 2 or 3 lampholders fed by each transformer, and the answer is the same because each ELV luminaire is still complete within itself, and has an individual connection to the ELV output of an energy converter.

split the LV side so each transformer is switched separately, and it's still 10 points.

Now move to LED, 10 luminaires supplied by several drivers each supplying several luminaires.
Same answer, as each luminaire is still an individual fitting.

It helps if you realise that ELV wiring is often installation wiring. The change form installation wiring to equipment wiring doesn't always happen at the transformer / driver.