transformer/wiring

[ramundo]

I am attempting to use two 300 Watt transformers for three fixtures and I'm not sure if what i'm trying to do is correct advisable and to code. The transformers are for low voltage lighting and are 120V 50/60Hz 2.7 Amp input and the output is 12V 25Amp. What i'd like to do is reduce the output wires from the transformers from 4 to 2 pairs by bridging them together. Assuming this is possible, from there i would have three pairs of wires that travel a distance of about 4-5 feet to three terminal bars and i'm not sure what gauge to use. Any suggestions?

[Homer]

You've posted this same question twice on the US Code section of this site. That makes this one number three!

As answered there, you can't just parallel transformer secondary windings.

You need to size your transformers for the load required. You have three lights and two small transformers. You should have either one transformer large enough for the three lights, or three small transformers individually connected to each light.

Homer

[ramundo]

thanks homer,

i posted the first time without logging in but i guess that would have been good enough. i'm using two 300W transformers to power twelve 35watt lamps since I was told that 600W transformers are not permitted due to code restrictions. Thanks again for your time and knowledge!

ramundo

[Homer]

If your three fixtures have a total of 12, 35W bulbs, then that's 140W per fixture. That's still a hefty current for each fixture at 12V. I would invest in another transformer and power each fixture individually. You will be able to use 14 gauge wire if you do it this way.

Under Canadian Codes, you have a Class 1 circuit, where you have an output voltage less than 30V. The maximum power for such a circuit is 1000VA or 1000W if you're talking about lights. That should only be loaded to 80% or 800W. See CEC 16-004 and 16-100.

I'm curious as to where your 600W restriction comes from, other than the physical limitations of dealing with large gauge wire.

Homer