Lighting Systems 30V and less, uses not permitted

[john h]

As an inspection agency, we get lots of questions on why Article 411.4 disallows concealed wiring for lighting systems 30V and less and allows fire alarm and thermostat wiring to be concealed. Why? Is it the higher wattage?

 

[BAHTAH]

Re: Lighting Systems 30V and less, uses not permitted

I don't think it is the higher wattage but the higher currents and fire hazard possibilities associated with these types of installations as compaired to themostat and other LV low current loads.

 

[pierre]

Re: Lighting Systems 30V and less, uses not permitted

It is actually the difference in the ENERGY that is available. There is more energy available in the low voltage lighting system.

Pierre

[ September 26, 2003, 01:39 PM: Message edited by: pierre ]

 

[jhines]

Re: Lighting Systems 30V and less, uses not permitted

2002 handbook states "The installation requirements of 411.4 recognize that shock and fire hazards still exist, even with low-voltge systems."

 

[iwire]

Re: Lighting Systems 30V and less, uses not permitted

These low voltage lighting systems can certainly start a fire when installed improperly.

The systems we install often use a 300 watt 12 volt transformer.

That means the transformer could provide 25 amps at 12 volts, have someone use thermostat wire because "it is low voltage" and you will easily burn up the wire.

With this size transformer the instructions recommend 10 AWG up to 4 AWG to handle voltage drop.

 

[flightline]

Re: Lighting Systems 30V and less, uses not permitted

This link from a previous thread might be of intrest.

 

[iwire]

Re: Lighting Systems 30V and less, uses not permitted

Originally posted by john h:
As an inspection agency, we get lots of questions on why Article 411.4 disallows concealed wiring for lighting systems 30V and less and allows fire alarm and thermostat wiring to be concealed. Why? Is it the higher wattage?

It can be concealed, with the correct wiring method, zip cord, thermostat wire etc. are not one of the correct methods.

 

[Guest]

Re: Lighting Systems 30V and less, uses not permitted

Originally posted by iwire:
These low voltage lighting systems can certainly start a fire when installed improperly<snip>and you will easily burn up the wire.

We can prove this easily by jump-starting a car by using 22 AWG jumper cables-- or even 12 AWG, etc. It's the Amps that burn the undersized wire. 22 AWG would go white hot.