Landscape lighting transformer and wiring

[iwire]

Dennis first of let me say I was brought into the trade with the impression that I could do anything and use any product if it was 'low voltage'.

"It's low voltage the NEC does not apply", it's never been enforced etc.

As time goes on I find that in fact there is little that I do that the NEC does not have a say in.

Yes this is so but the response was that every cable allowed in a structure is defined by the NEC.

Can you point out an application an EC might do in a structure that the NEC does not have a say in?

 

[msoengineer]

Wire/Cable allowed in the home

Wire/Cable allowed in the home

I have a job installing a landscpe lighting system at a home and the question came up about running low voltage wiring through the basement so that all the transformers could be mounted in one location. I have 2 600w trans and was going to use 10/2 landscape wiring to run from the trans to the fixtures. I checked the code book but I can't find anything that indicates this can't be done. The only thing that worries me is that there is a higher amp on the low volt cable and would it be safer to run this in pipe?

As others have mentioned, LV cable is not allowed to be used indoors between the panel and the transformer, nor does it meet the necessary smoke requirements for indoor use.

The only solution I am aware of would be to use a 2 wire + gnd (3 wire) UF-B to run from the panel and out to the transformer. NM, romex, is not intended for direct burial and should not be used outdoors. 3 wire UF-B is allowed to be used as NM cable per 340.10(4) as it meets parts II and III of 334.

From the transformer out to the lights you could use either a LV cable or a 2 wire UF-B cable.

As others have mentioned you should keep the transformer as close as possible to your loads to prevent Voltage Drop.

As with any installation, the decision is not up to you, it's up to the Authority Having Jurisdiction in your area, aka Code Inspector. When in doubt check with them as they have the final word. In many areas NM is no longer to be used in the home.