Lighting Circuit.. Surely This Isn’t Right?

[saveloy]

"what sparky installs a cieling light allowing for a 60watt light bulb? on new builds and previous firms i worked for we had to allow at least 150w per ceiling fitting (diversity)"

Agree 100%

When I did my 2330 we were told to always assume that a normal light fitting (pendant) would be taking a 100 watt bulb so our caculations would have to reflect this. This was to allow for the fact that this is what the end user may fit to the fitting. Not arguing with Sparky york though as his method is even safer. You have to expect that the average house holder is not going to take a blind bit of notice of the rating on the lamp. Invariably they will just stick the brightest bulb they can find, into the fitting!!

 

[TPES]

Lets say you have a lounge with 2 x big fancy 5 light chandelier fittings, and the end user fits 60w bulbs in each fitting. 10 x 60w bulbs

Theres 600w on 2 pendants alone in one room.

Then a set of mains downlights in the kitchen.. Its also very likely these 2 rooms will be lit up at the same time.. you could easily be upto or over 1000w just on these 2 rooms never mind the rest of the circuit.

I would always wire and account for these situations.

Best to be safe than sorry.

 

[jeremy]

Can some one please explain to me please as i am having a bit of a senior moment, why you cant have 1mm and 1.5 on the same circuit ? Is it because the 2 numbers don't fit into the box on the Schedule of inspections?

Also having read a bit more, from the recesses of my 1664 addled mind 1mm 6A 1.5 10A 2.5 20A. This I seem to remember takes into account the fact that the eejit householder will try and bugger your plans for providing him with a safe install. Remember divide by 2 if the same eejit covers more than 50mm length of one circuit in insulation.

 

[just add water sparks]

I also work on the premise that about 12 lights on a circuit is ok as ohms law 1200 divided by 230 = 5.21amps .Other suggestions have said no more than 6x12v 50w fittings on a circuit!! This seems to me to be a restrictive amount to me, i may be wrong & i dont mean to be critical just trying to get an answer.How do you work out the loading to an individual e.l.v 12v 50w lamp if you use ohms law , 50 divided 12 it works out 4.1 which surely cant be 4.1 amp each fitting. Do you also take into account the transformer load??Please could someone tell me the loading of an individual e.l.v 12v 50w lamp & how this is calculated????? It would be very much appreciated if anyone can help with this.

 

[Stuart King]

Would someone please come up with the answer

 

[Tag]

Evey lighting point should be calculated as a min 100w bulb regardless of whats actually installed

 

[ian.settle1]

Would someone please come up with the answer

Why this posting is nearly 12 months old

 

[Tag]

...what was the question?

From the first post I'm counting 24 lighting points. 24*100w = 2400w / 230 = 10.43A. I'd say 1mm t+e is border line if ref method is 101 but the volt drop is very high. Best use 1.5mm t+e on a 16A breaker in my opinion.

 

[Sintra]

...what was the question?

From the first post I'm counting 24 lighting points. 24*100w = 2400w / 230 = 10.43A. I'd say 1mm t+e is border line if ref method is 101 but the volt drop is very high. Best use 1.5mm t+e on a 16A breaker in my opinion.

If you are using ref method 101 as stated you can not use a 16A breaker as your 1.5mm T&E is rated at 13A.

Table 4D5 BS 7671 2008

 

[Tag]

ah your right, I think I ment 100...

 

[Stuart King]

Its the same question as a year ago but there was no answer
50w at 230v i=p/v i=50/230 i=0.28 amps
50w at 12v i=50/12 i=4.2 amps
Is this correct?

 

[Tag]

50w at 12v i=50/12 i=4.16

 

[Stuart King]

Always round up.
Is the 12v sum correct?

 

[Tag]

I was told to never round up... I think that WAS how it was done but I was recently told different

 

[Stuart King]

Anyway,is the 12v sum correct?