Electrician Foreman

[rmlecates]

A low voltage digital addressable lighting company makes the claim in their brochure that their control circuit may be run in the same cable or raceway as the lighting circuit. They also claim that the circuit may be run as class 1 or class two. They use Article 300.3 to back that up and say as long as the insulation of the control circuit is equal or greater than that of the lighting circuit then it is ok. However the FPN of 300.3 refers to 725 for specifics on class 2 and class 3 circuits. There it clearly states that a class two circuit shall be separated unless meeting some of the exceptions in which would not be done if wired the way recommend. The control circuit is a class 2 circuit. Does simply changing the insulation make that a class 1 or are classes determined by the power supply and thus making their claim a violation?

 

[ceb58]

A low voltage digital addressable lighting company makes the claim in their brochure that their control circuit may be run in the same cable or raceway as the lighting circuit. They also claim that the circuit may be run as class 1 or class two. They use Article 300.3 to back that up and say as long as the insulation of the control circuit is equal or greater than that of the lighting circuit then it is ok. However the FPN of 300.3 refers to 725 for specifics on class 2 and class 3 circuits. There it clearly states that a class two circuit shall be separated unless meeting some of the exceptions in which would not be done if wired the way recommend. The control circuit is a class 2 circuit. Does simply changing the insulation make that a class 1 or are classes determined by the power supply and thus making their claim a violation?

To be clearer it is 300.3 (C) (1). As long as you have and keep the mfg. instructions then you should be ok as long as the insulation is rated the same as the lighting circ.

 

[don_resqcapt19]

Take a look at 725.130(A) Exception #2.

 

[Jim W in Tampa]

You still must deal with conduit fill and maybe derating. And as soon as they add any thing to my pipes they just voided the warranty. If insulation and voltage pass then sure they can add.

 

[jusme123]

does the same apply to commercial garage door openers, with reference to low voltage mixed with 208/ 3 phase?

 

[e57]

does the same apply to commercial garage door openers, with reference to low voltage mixed with 208/ 3 phase?

Low voltage can mean lots of things - to Linemen 208Wye is low voltage - if you're talking ~24Vac? That stuff comes in a few flavors too... i.e. Class 2 & 3, much of the stuff like 240/120 through 480/277 is considered Class 1. (And those use chapter 3 wiring methods... )

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.
Class 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.
Class 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.

Now back to the OP...

They also claim that the circuit may be run as class 1 or class two.

I think this is what they are going on about...

725.52 Wiring Methods and Materials on Load Side of​

the Class 2 or Class 3 Power Source.

Class 2 and Class 3

circuits on the load side of the power source shall be
permitted to be installed using wiring methods and materials
​

​

in ​

​

accordance with either 725.52(A) or 725.52(B).

​

​

(A) Class 1 Wiring Methods and Materials. ​

​

Installation

shall be in accordance with 725.25.
​

​

Exception No.1: The derating factors given in
3IO.I5(B)(2)(a) shall not apply.
Exception No.2: Class ​

​

2 and Class 3 circuits shall be

permitted to be reclassified and installed as Class 1
circuits if the ​

​

Class 2 and Class 3 markings required in

725.42 are eliminated and the entire circuit is installed
using the wiring methods and materials in accordance with
Part II ​

​

Class 1 circuits.

​

​

FPN: Class 2 and Class 3 circuits reclassified and installed
as Class 1 circuits are no longer Class 2 or Class 3 circuits,
regardless of the continued connection to a Class 2 or Class​

3 power source.
​

i.e you could run it in pipe with THHN for line voltage (Class 1), and THHN (a Class 1 method) for the low voltage, and call it all class 1. (BTW this is not always the best design)

Alternatively - they would need to be seperate... (i.e. using say class 2 cable for the class 2....)
​

 

[DARUSA]

Be careful when you reclassify a circuit because you really have to meet the chapter 3 wiring methods .
No splice can be spouse and you transformer have to have no electrical live parts espouse like a regular class 2 transformer!!!
No class 2 and 3 wire is allowed w/power conductors in the same raceway or enclosure( unless you have a divider )!!!