Why no Ground required

[brother]

Some one asked me why no ground was required for the class 2 , 3 wiring in Article 725. I basically said it had to do with the low voltage (under 30 volts I believe) and with most people this is below their perception/feeling of shock.
Is this basically true for article 725? I know there are exceptions when it comes to swimming pools, marinas, boat areas and spas when it come to class 2 wiring.

 

[zbang]

I'm going to completely make up an answer here- because the fire hazard is so much lower with low power sources. Remember that the NEC (aka NFPA 70) isn't really a safety code, it's a fire-prevention code (the FP of NFPA). And simply grounding a source without providing a fault current path doesn't do much, if anything, for personal safety.

(I'd also like to hear other takes on the subject.)

 

[tortuga]

Low shock risk from touching one conductor while also touching something grounded.

What is strange is how 411.6(A) prohibits low voltage lighting from having one conductor grounded.
That seemed odd at first to me, the logic seems to be you cant get a 30V shock if you touch one hot conductor and ground.