Halolite Low voltage lights

[hagar the horrible]

Been looking for some technical info regarding installation of lv lights..i have a Transformer rated at 100-210w/va.... i have been told to keep the lv leads less than 2 mtrs in length..this will cause me problems from an installation point of view...what i have done is a single 1mm twin from the transformer and wired all the lights in parrallel on 12 feet of wire the lights seem to work ok ..is this this an acceptable methed to use a lv transformer like this...the load is 120 watts which is a lot less than the rated output of 210 watts..there is a small votage drop between the first and last light but its very hard to notice a difference in light output

 

[breezer]

the titanic "seemed alright" untill it hit an iceberg

you would bebetter off running single 1mm cables to each light, especially the furthest away ones

as it is you are close to the limit of the cable you are using

 

[hagar the horrible]

Thanks..i think i might run 1.5 0r even 2 mm cable as there is nothing permanent as yet..easy to change the cable.

 

[breezer]

2mm that sounds interesting

 

[hagar the horrible]

why does the sound interesting ?

 

[RF Lighting]

I would definitely upgrade the cable from 1mm². The MAXIMUM load for 1mm² 'twin' (presume you mean twin and earth) is 11 amps. The circuit you described (120W at 12V) will use a current of 10A. This seems fine at first glance but you say the transformer is rated at 210W. This would allow you to draw a current of 17.5A without the transformer overloading and cutting out. 17.5A is very close to the maximum current limit of a 2.5mm² cable. With your current setup all it would need is ONE lamp of the wrong rating fitting to the circuit (even as little as an additional 15W (replacing one 20W lamp for a 35W lamp)) to over load the cable and cause a real fire risk. No matter how careful you are someone else may come along and fit a lamp of the wrong rating.

BTW where do you propose buying your 2mm² cable from?

 

[breezer]

BTW where do you propose buying your 2mm² cable from?

thats why i said "2mm that sounds interesting"

 

[hagar the horrible]

i assume that 2mm cable is not available ..judging by your comments..all other comments you have made are noted and are of value..cheers..Keith.

 

[hagar the horrible]

I would definitely upgrade the cable from 1mm². The MAXIMUM load for 1mm² 'twin' (presume you mean twin and earth) is 11 amps. The circuit you described (120W at 12V) will use a current of 10A. This seems fine at first glance but you say the transformer is rated at 210W. This would allow you to draw a current of 17.5A without the transformer overloading and cutting out. 17.5A is very close to the maximum current limit of a 2.5mm² cable. With your current setup all it would need is ONE lamp of the wrong rating fitting to the circuit (even as little as an additional 15W (replacing one 20W lamp for a 35W lamp)) to over load the cable and cause a real fire risk. No matter how careful you are someone else may come along and fit a lamp of the wrong rating.

BTW where do you propose buying your 2mm² cable from?

how do i calculate the cable size please ?

 

[hagar the horrible]

I had a bit think about your comments..i have six lights on this cable ,what if i split the lights up into 3 pairs and have a 1mm cable going to each pair...with 35 watt bulbs each pair would draw 5.8 amps..
if i use 25 watt bulbs 4 amps...do you think this is safe ?..

Ps..not a sparky..DIY...but i want and understand the need to get this right for safety.

 

[shawn]

Hi

I have a similar problem in that I am putting in Halogen downlighters into my house, 4 low voltage spots 12v 20 Watts.

What I dont understand is that the transformer I have bought says, that "the output leads must not exceed 2m in length", Im confused to why they have stated only 2 meters.

It looks like im going to need 3 or possible 4 meters in total to get to all the spots from the transformer.

I had just bought 0.75mm 2 core flat flex which I was thinking of running to each of the lights, about 3/4 meters in total, but having read the posts above im completely confused to know if this is safe or not.

The cabling I have bought says 6 amps 1440 watts, which I thought should of been plenty as I only have 4 - 20 watt 12 Volt spotlights so surely thats only 80 watts. Dont understand the post above about the total amps of the circuit. Could anyone give me some advice about what im planning to do or not, if its safe or not.

If not whats the best solution to make my wiring safe please?


=====================
see forum rule 20

 

[securespark]

Shawn

See your other post.