Spot lights 12v / 230v ??

[levstar]

Hi looking at putting some spotlights in my bedroom and have found two potenetial sets I am thinking of buying. Both of these are double insulated however one set it 12v and another 230v. I was hoping for a bit of advise re:

1. What are generally better, I am under the impression 230v are more versitile i.e adding dimmmers etc, however I am told the bulbs last longer on 12v?

2. Looking at the 12v lights I am interested in they come fiited with a 3 amp plug, Am I able to remove the plug and wire it in to a junction box within my lighting circuit? is there any need to down rate the fuse to a 3 amp if I incorporate this in my lighting circuit or was this fitted in case it was plugged in to the ring final circuit.

3. Also Re the 230v lights looking at these the five lights receive the PH and N , what is the best way to wire these i.e daisy chain from one light to the next PH to PH, N to N basically adding lights or should use a 20 amp junction box and only have one PH and N go to each light (thinking this might be a bit messy with five lights)

As always your advise is greatly appreciated.

 

[Adam_151]

1. What are generally better, I am under the impression 230v are more versitile i.e adding dimmmers etc, however I am told the bulbs last longer on 12v?

240v fittings cost less per point to install because there is no trasformer, and also there is no transformer to fail, and also have no tx losses

12V fittings give a better quality of light and (I think!) slightly more lumens/watt, the lamps tend to last longer.

Dimming is a bit of a can of worms, yes 240v ones can be dimmed using standard phase cutting dimmers, but; you have to rate the dimmer at at least twice the wattage of the lamps unless it has a halogen wattage indicated on it, in order to avoid the low resistance of cold halogen lamp filaments causing the traic to fail; and accept that dimming any halogen lamp is at odds which the design of the lamp* and will shorten the life. With 12v fittings, in addition to above, the transformers have to be dimmable types and the dimmer you buy has to be suitable for reactive loads

Consider wiring your lights in smaller switched groups to avoid the dimming issue

2. Looking at the 12v lights I am interested in they come fiited with a 3 amp plug, Am I able to remove the plug and wire it in to a junction box within my lighting circuit? is there any need to down rate the fuse to a 3 amp if I incorporate this in my lighting circuit or was this fitted in case it was plugged in to the ring final circuit.

Quite likely, but it is also likely that you may be looking at somenthing not designed to do the job you want it to do, have you a web link?

3. Also Re the 230v lights looking at these the five lights receive the PH and N , what is the best way to wire these i.e daisy chain from one light to the next PH to PH, N to N basically adding lights or should use a 20 amp junction box and only have one PH and N go to each light (thinking this might be a bit messy with five lights)

You should wire them all in one long 'daisy chain' and at each loight point place a JB201 (small 20A round joint box, small enough to be withdrawn through the hole the light fits in), making sure to keep the earths continous and then connect a short piece of 0.75mm² 3 core fix from JB to lamp. If using 12v fittings, you should wire in a similar way and place a tx per fitting, try and avoid the ones with a transformer for several fittings as these tend to cheap pre-wired kits

 

[ELZ4742]

gu10s have a tendancy to pop alot more due to voltage fluctuations.

 

[levstar]

Hi Thanks for the info as always top draw... Here is the link to the 12 v lights

http://www.homebase.co.uk/webapp/wc...logId=1500000701&langId=-1&searchTerms=724458

With the 240v lights as there they are double insulated they dont as for an earth to be fitted. they also come with a connector block on them so will I still need a J/B at every light could I not place the 2 PH and N wire in these boxes to daisy chain?

Incidentlly there will be good access to these lights as they will be in the loft space.

Thanks

 

[ericmark]

As to dimmers no quartz halogen tungsten lamp should be dimmed it will reduce life of the lamp. The whole idea of the 12v system is to control the voltage so the correct temperature is reached thus extending lamp life and increased output. Where the voltage is not stable they are very good but if there is no problem with voltage the 230v version are cheaper and don't have inverters to go wrong. The modern 12v type is not a transformer but an inverter which corrects the voltage as well as reducing it. Although the 12v lamp will be brighter and last longer one is limited as to what lamps can be used. There is a min as well as max output so one can't often fit LED lamps even though they will fit. Also cold cathode lamps will not work on 12v so one has to use the correct lamp it is designed for. Angle of light is also a problem with a vast variation so although it may work OK when fitted once first lamp blows getting a replacement at same angle is not so easy.
The little pods used to light the picture on the wall are really good. But as general lighting they remind me of the TocH candle and are next to useless.

In bedroom I use the 230v type next to bed as reading lamps and have used cold cathode as better spread of light. But book is within 3 foot of lamp.

In bathroom I have 4 x 12v types mainly as they also give off heat and were free. They are very old and use a transformer not an inverter and the transformer would make a good door stop it's that heavy. I found when using tungsten in all both types lasted about same amount of time. But easy to buy 230v type sold in £1 land.

 

[levstar]

Hi Just curious re:

You should wire them all in one long 'daisy chain' and at each loight point place a JB201 (small 20A round joint box, small enough to be withdrawn through the hole the light fits in),

If I am having 6 lights will this then mean I will end up with 6 J/Bs if so is this a problem. Should I try to minimise the number of J/Bs on the circuit?

Thanks

 

[Adam_151]

Its not a problem, and you'll find that if you used 12v fittings, most transformers are sealed and have a 6" tail of connection flex from the primaryy side anyway, so unavailable really.

Better to do it that way rather than have a spiders web of flexes running off from a central point in your loft

 

[levstar]

Thanks for this I have opted for the mains supplied lights in the end. They do not seem to require flex just twin (PH and N) straight into a connector block which is part of the fitting.

As a result I will use the J/B method suggested should be a tidy job all being well.

Thanks once again

 

[Adam_151]

I'm not keen of T+E stright into downlights, check the shape of the cable grip, often find that it mangles the outer sheath on T+E, probably do able if you have only T+E per fitting though (ends up a right mess with 2, normally findd them with unsheathed conductors hanging loose, and often with earths snipped off too if there isn't a holding terinal for them!),... a bit of heat resisant 3c flex also helps to keep the 70C rated pvc twin and earth away from the fitting

 

[ban-all-sheds]

If I am having 6 lights

If you are having 6 lights have you added up what the total wattage will be, and considered whether it's an efficient way to light the room?

What is above the bedroom? If you're in a flat what are you going to do about compliance with Parts B & E of the Building Regulations? If it's a house with a loft above it what are you going to do about Parts C and L (and possibly also B as well)?

 

[riveralt]

Thanks for this I have opted for the mains supplied lights in the end. They do not seem to require flex just twin (PH and N) straight into a connector block which is part of the fitting.

As a result I will use the J/B method suggested should be a tidy job all being well.

Thanks once again

Just make sure you wire them in parallel and not series.

 

[ban-all-sheds]

So, there are at least 3 ****s out there who don't think I should have asked the OP whether he had thought about the efficiency of his lighting and whether he had thought about how he would comply with the law.

Would any of you care to justify why those questions were unacceptable, i.e. why they wanted to send a message saying that efficiency is of no concern and it's OK to break the law?