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Class 1 Circuit. The portion of the wiring system between the load side of the overcurrent device or power-limited supply and the connected equipment. The voltage and power limitations of the source are in accordance with 725.21.
' F- Q3 m0 E4 L1 U# pClass 2 Circuit. The portion of the wiring system between the load side of a Class 2 power source and the connected equipment. Due to its power limitations, a Class 2 circuit considers safety from a fire initiation standpoint and provides acceptable protection from electric shock.
9 X5 y$ @# P- q8 sClass 3 Circuit. The portion of the wiring system between the load side of a Class 3 power source and the connected equipment. Due to its power limitations, a Class 3 circuit considers safety from a fire initiation standpoint. Since higher levels of voltage and current than for Class 2 are permitted, additional safeguards are specified to provide protection from an electric shock hazard that could be encountered.+ Y5 r8 y' `' y% V) w" G+ Y
725.21 class 1circuit classifications and power source requirements.
" J- Z/ p# f# ?' ^* y3 m! K: o0 V" ]Class 1 circuits shall be classified as either class 1 power-limited circuits where they comply with the power limitations of 725.21(A) or as class 1 remote-control and signaling circuits where they are used for remote control or signaling purposes and comply with the power limitations of 725.21(B).
0 l: O/ @% w" G# ~3 Q(A) class 1 power-limited circuits. These circuits shall be supplied from a source that has a rated output of not more than 30 volts and 1000 volt-amperes.0 G: L# p& t! K' n, b
(1) class 1 transformers. Transformers used to supply power-limited class 1 circuits shall comply with article 450
5 ?. o& {: U% b+ @# T7 N. D(2) other class 1 power sources. : m4 f2 ]( ~! p8 E! A( A) F
(B) Cass 1 remote-control and signaling circuits. These circuits shall not exceed 600volts the power output of the source shall not be required to be limited |
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