2 low voltage transformers on 1 circuit?

[CJT]

If you have 120V at the far end, just split the wire. I thought the whole point of the exercise was that a driveway separated the lights from the source of power.

[dchou4u]

Thank you all for your input.

I spent the morning today tracing the buried wires and found the junction where the single wire coming from the 600W transformer is split into different branches running to different areas of the yard. This junction is on the other side of the driveway from where the 600W transformer is located.

I think I have found a good place to relocate the 600W transformer so that it will be on the same side of the driveway as where this junction is. My plan now is to run two 8 guage wires from the relocated 600W transformer to this junction. Then let the existing buried 12 gauge wires run from there to each spot. It will be hard for me to change out the 12 gauge wires after the junction, since they cross walkways and etc. But from the transformer to this junction, I have a clear path... which is great news! The two 8 gauge wires will each handle 1/2 the yard. The total length of each leg is about 40' from transformer to the junction (8 gauge), and then another 40' from junction to each spot (12 gauge). Most of the light fixtures are after the junction.

By the way, I used my voltage meter to measure the voltage drop across the 2 wires coming out from the transformer. I had expected to see 12V across them, but I dont detect a voltage drop. But somehow it works... :) How do you measure the voltage at each spot of the run if I cannot even detect a voltage drop across the 2 wires at the transformer? Thanks for any tips....

[RBM]

Use a volt meter. You shouldn't have any drop at the transformer, but with the lights on, testing across the two conductors, you should get drop the farther away from the transformer you go

[Stormin Mormon]

Do the transformers supply AC or DC for the 12 volt power?

[peter]

Bad news. If you merely shorten the distance from the transformer to the junction, without changing the wiring after the junctions, this would brighten all the lamps, so the downstream lamps will still be dimmer than the closer one. Nevertheless, it is a safety improvement to change out the overloaded 12 gauge wires. Perhaps your contractor would do this for free if you could convince him the wires are overloaded. Is he even a licensed electrician?

You wouldn't happened to be using a DC meter to measure AC voltage? "voltage drop" means a voltage on the same wire at the two ends, not the output of a transformer. The output of the transformer should be 12V, and the voltage drop on the wire from the transformer to the junction would probably be less than 1V on each leg.

So some of the light fixtures are before the junction?? By definition there has to be a junction for the light to connect to.

Home depot may have free classes in electrical wiring. You can then show the instructor your wiring plan and get his blessing.

[CJT]

That seems an odd way to pose such a question. A transformer without more will _always_ provide AC. Provision of DC requires what I would call a power supply, rather than a transformer.

Rarely would one go to the trouble to provide DC for lighting -- what's the benefit?

[Tony Hwang]

Hmmm, DC? Forgot about Edison vs. Tesla?

[dpb]

Tony Hwang wrote: ...

Hmmm...trying to recall who "won"...

--

[Don Wiss]

On this page it is clearly labeled DC Transformer:

Less voltage drop over long distances and reduces radiated RFI.

Don (e-mail link at home page bottom).

[dpb]

...

Hmmm...score zero for sarcasm, I guess... :(

--

[Don Wiss]

Tesla won. You can read about it here:

Don (e-mail link at home page bottom).

[dpb]

CJT wrote: ...

Unless, of course, input is DC... :)

--

[RBM]

Seems to me, Tesla won the first round, but when you compare their backers, Westinghouse and General Electric, Edison won the war

[dpb]

The technology of DC vis a vis AC for power distribution was the question, not the future state of pioneering companies, though...

--

[CJT]

No, but that was settled some time ago.

[CJT]

That doesn't make it right.

Maybe in a long haul high voltage transmission lines there might be a significant difference, but not in Malibu lighting. That's like citing skin effect in household wiring.

[CJT]

Good point. Then it will provide smoke.

[Stormin Mormon]

Do the transformers deliver AC or DC?

[Stormin Mormon]

The benefit of providing DC for lighting, is that you can feed DC from both ends of the wire.

Of course transformer delivers AC, but I didn't feel like asking "does the module containtaing a transformer have a rectification circuit, so that it would provide DC, or is it simple secondary winding, providing 60 hertz AC low voltage output"?

[Stormin Mormon]

Pulsating DC goes through a transformer.