mixing of fire alarm wire and others

[aharrigan]

A special shielded room for testing has two fire alarm systems in it. One for a local FM 200 system and one for a general building alarm.
These systems must pass thru a filters to get into the room. The FM system installer used three filters. There is on filter left and it has a 120v signal
passing thru it to get to the FM fire panel for shunt trip of a panel in the room. This filter has multiple lines that can pass thru into the room but all go thru a common nipple to get into the room. The building fire alarm system by another company want to run his wire thru this filter to activate a general building alarm in the room. Is it permissible to mix his wiring and the shut trip wiring thru the nipple into a common junction box in the room?

 

[Smart $]

Not sure what you mean by filter(s) in the context of your post. The only thing it puts me in mind of are intrinsically safe barriers, which would mean the circuits are running into a classified hazardous location. Can you elaborate/clarify?

I know enough to get by, but I am no fire alarm system expert. That said, more details are necessary for a compliance determination under the NEC. The wiring methods for each circuit will have to be classified under Article 760 Fire Alarm Systems and Article 725 Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits.

 

[aharrigan]

The filters are form the controls of RFI and EMI energy used to filter inputs such as data, telephone, fire alarm circuits and power into
shielded rooms for the testing in this case cell phones.

 

[Smart $]

The filters are form the controls of RFI and EMI energy used to filter inputs such as data, telephone, fire alarm circuits and power into
shielded rooms for the testing in this case cell phones.

Unless a filter changes a circuit from non-power limited on the supply side to power limited on the load side, then they will have no bearing on the determination whether the circuit wiring can pass through a common nipple.

 

[gadfly56]

NO!

NO!

You may not mix power limited fire alarm with non-power limited circuits in the same conduit. I don't have my book handy, but I think it's in article 760.

 

[Smart $]

You may not mix power limited fire alarm with non-power limited circuits in the same conduit. I don't have my book handy, but I think it's in article 760.

While I agree with your "basic" assessment, it may not be that simple. Seems to me we are discussing the mixing of a FA circuit with a 120V shunt trip circuit. What is in question is whether the FA system powers and controls the shunt trip circuit. It likely does control it, but it may not power it. That would make the determination subject to Article 725 and 760 requirements. Also, it has not been established whether the circuit to be added is NPLFA or PLFA. FWIW, Class 2 circuits can be in the same raceway or enclosure as PLFA circuits [760.139(B)].