Do I have to connect only ONE end of a string of 32 lights to a 300 Watt 12V transformer or can I connect TWO separate shorter strings of 16 lights to the transformer?

By asking this question you are probably not quite ready to take on this particular task.

You may or may not get lucky and receive some information in an answer here!

If you hope to get enough information on this site to be able to do this job properly and safely, please do not rely on getting accurate information about such a potentially dangerous subject.

Really, don't do this one yourself. Electricity is far too dangerous to handle if you have not been trained how to do this work.

How to do this job depends entirely on the Wiring Codes or Regulations for the locality (Town/State) and on the exact location where you wish to install the lights. If they are to be placed outside your house anywhere that is subject to rain or damp, or anywhere else subject to water splashes or spray - such as in any room supplied with running water pipes, like a kitchen, bathroom, shower room, etc., or in a pool-side area - in many places nowadays it is actually illegal to attempt to do this kind of work unless you are already a licensed electrician.

If you don't want to go to your local library or bookstore - to find and read some books about electrical wiring and appliances and how to install them safely, and to find out about your local Wiring Codes and Regulations - then the best advice anyone should give to you is to call a licensed electrician either to do the job for you or to advise you what you may be allowed to do yourself.

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First of all you have to find out the voltage of the light bulbs and how they are connected to make the string of 32 lights in total.

PARALLEL CONNECTION
It is possible that the light bulbs run on 12 Volts each and are connected in parallel to one another across the 12 Volts output of the transformer. Each bulb may be rated at about 9 Watts. (300 Watts / 32 = 9.375 Watts power per bulb.)

If that really is what the bulbs are, and they are connected in parallel as described above, you can separate the single string of 32 bulbs connected in parallel into two separate strings, each having 16 bulbs connected in parallel.

SERIES CONNECTION
The other - less likely - possibility is that the bulbs run on only 0.375 Volts each and that they are all connected in series across the 12 Volts output of the transformer. (32 x 0.375 Volts= 12 Volts.)

If that is the case then you can split the single string into two physically separate strings but you must still connect the two strings electrically so that all 32 bulbs remain wired in series across the 12 Volts output of the transformer.

If you don't do this right, and you connect each of the serially-connected string of 16 bulbs directly across the transformer, two things will happen:

i) the transformer will be seriously overloaded and could catch on fire because the current taken by each string of 16 series-connected bulbs will now be 50 Amps instead of 25 Amps. That makes a total of 100 Amps taken from the transformer instead of the original 25 Amps when all 32 bulbs were connected in one string.

and

ii) all the lamps will glow very brightly for a short time until one of them burns out, at which point all the bulbs in the string will go out because they are connected in series. (The first one to burn out will break the series circuit.)

IF YOU NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.

If you do this work yourself, always turn off the power at the breaker box/fuse panel BEFORE you attempt to do any work AND always use a meter or voltage indicator
to insure the circuit is, in fact, de-energized.

First answer by Martinel. Last edit by Martinel. Contributor trust: 142 [recommend contributor]. Question popularity: 1 [recommend question]