12V Transformers for outdoor lights

zak1976

Am I right in thinking that a 20.4 VA transformer will only power 4 x 5W bulbs in series? If I tried to add another 20W through the transformer would I blow the thing up?

If so, any suggestions where I can buy a better transformer cheaply....... currently have 2, one powers 35W spot and another 4 x 5W lights.......

The reason I ask........ I want to add another 3 lights in my pond and I'm sick of drilling holes in the wall of my house to put another cable through!!!!

Any help would be appreciated.

Many thanks

YorkshireBoy

zak1976 wrote:

Am I right in thinking that a 20.4 VA transformer will only power 4 x 5W bulbs in series?

No, you connect them in parallel.

zak1976 wrote:

If I tried to add another 20W through the transformer would I blow the thing up?

Yes.

zak1976 wrote:

If so, any suggestions where I can buy a better transformer cheaply.......

Any electrical wholesaler will supply you with one. Just make sure (if it's to be installed outdoors) that it's "rated" for use outdoors.

JimArnold

You run bulbs in parallel - that way they all get the same maximum voltage and each draws their own 20 watts of current.


in general you should keep low voltage cables to a minimum length remember that volts x amps = watts So 20 watt needs 0.08 amps at 240v but 1.7 amps at 12v

So you only need one cable through the wall and several outdoor transformers but this also means properly protecting the mains cable and having a separate RCD on that circuit

TLC direct are good suppliers eg

http://www.tlc-direct.co.uk/Main_Index/Transformer_Index/Waterproof_Transformers/index.html

zak1976

Yes, sorry, thinking about it, it's parrallel, just not a ring circuit........ Brain not functioning!