When was this allowed?

[MAK]

I was called out to a department store Friday evening to fix a delayed egress device on a fire exit door. When I arrived and opened up the device (Von Duprin Chexit) I found it was wired with cat3 (24awg solid).
The conductors were breaking off quite easily and I had suggested that it be rewired with 18awg stranded to prevent the problem from reoccurring. When I looked at the raceway (3/4" emt) I found thhn conductors with 120 vac in the same raceway as the LV wiring 24vdc (class 2). I told the customer I could not rerun the cable in the same raceway and that I would have to run a few pieces of emt to make it happen. Customer declined, and I patched it up as best I could.

The building is 13 years old. I presumed that all of their other doors were wired in the same manner. I also had found some of the fire alarm horn strobe wiring in the same raceway as well. This building was in Massachusetts.

My question is when was it allowed to have class 1 and class 2 wiring in the same raceway?

 

[iwire]

It's allowed today under certain conditions.

Are the low volt conductors in raceways and enclosures over there entire length?

 

[MAK]

It's allowed today under certain conditions.

Are the low volt conductors in raceways and enclosures over there entire length?

No not the entire length. They came down one side, about 3 feet, above the doors (double doors) and then piped over about 5' to the power supply.
So a total of probably 8' out of 20' feet of the raceway has 120 vac thhn running with the lv cable and fire cable.
I don't suppose you could provide a code reference? I always operated on the basis that class 1 and class 2 wiring had to be in separate raceways or separated by an approved barrier.
I just assumed that I should not have pulled new conductors in the same raceway because I would then be in violation.

 

[JFletcher]

See 725.136.

 

[MAK]

See 725.136.

I read this section (NEC 2008) but I don't understand how it states that a class 1 and class 2 circuits are allowed to run in the same raceway (3/4" EMT) without a barrier or a minimum separation of .25 inches.
The installation I saw had thhn feeding the class 2 power supply 120vac and also had the class 2 circuit (CAT 3 cable 24vdc) in the same conduit for a conduit distance of about 8'. I do not see how any of those exceptions apply.

 

[hbiss]

My question is when was it allowed to have class 1 and class 2 wiring in the same raceway?

Don't know why you are arguing. You are correct and Jack (Fletcher) was just pointing out the Article so the others might see the error of their ways.

-Hal

 

[MAK]

My question is when was it allowed to have class 1 and class 2 wiring in the same raceway?

Don't know why you are arguing. You are correct and Jack (Fletcher) was just pointing out the Article so the others might see the error of their ways.

-Hal

Wasn't arguing. Thought there was something I may have misunderstood.

 

[JFletcher]

I read this section (NEC 2008) but I don't understand how it states that a class 1 and class 2 circuits are allowed to run in the same raceway (3/4" EMT) without a barrier or a minimum separation of .25 inches.
The installation I saw had thhn feeding the class 2 power supply 120vac and also had the class 2 circuit (CAT 3 cable 24vdc) in the same conduit for a conduit distance of about 8'. I do not see how any of those exceptions apply.

As far as I'm aware, a barrier is the only exception to having class 1 and 2 circuits in the same raceway. If they were ever allowed together in the past, sans a barrier, I do not know under what code cycle it changed.

The code ref was more to iwire's point that, under certain conditions, they are allowed together. I should have quoted that in my first reply. Sorry about that.

 

[MAK]

As far as I'm aware, a barrier is the only exception to having class 1 and 2 circuits in the same raceway. If they were ever allowed together in the past, sans a barrier, I do not know under what code cycle it changed.

The code ref was more to iwire's point that, under certain conditions, they are allowed together. I should have quoted that in my first reply. Sorry about that.

No appology needed, I was thinking there was going to be something in that section that would allow this install. Thank you for your response it backs up what I thought I knew about the code relating to this install.
I was just curious to know if anyone knew if this practice was allowed at one time or another.

 

[hbiss]

Actually the 2008 cycle removed previous langauge that allowed LV wiring to be "reclassified" as Class 1 by using LV conductors with the same insulation rating. Those could then be run with the power wiring ONLY if they were "functionally necessary" for the operation of the device that uses the power conductors. Rarely did anything meet that criteria and certainly not what you are talking about. Now it looks like the only thing they could share is a KO.

-Hal