ECN Forum Forums Code Related Discussion NEC & other Code issues Class A System

George with the proper use of isolation modules even a short in the addressable loop can be worked around with a class A system.

The majority of systems I install are fully class A. Few get the isolation modules.

The difference between a Class A Style 6 and Class A Style 7 is the isolation modules and the associated ability to operate under a fault.
I specify in most cases, a hybrid Style 6/7 which has a style 6 circuit, with an isolation module between each control panel and every 10 device on the SLC loop.

Can You T-tap with an addressable system? Code reference please

[This message has been edited by George Little (edited 05-15-2005).]

A class 'B' addressable SLC loop can be T-taped per minimum code.
A class 'A' loop could not because there wouldn't be a supply and return loop.
NFPA 72-2002 6.4.2.1

Most of the time, when I specify a class B circuit, I also specify no T-taps to ease the future troubleshooting burdens.

[This message has been edited by Ron (edited 05-15-2005).]

Thanks Ron. I'm not the sharpest tool in the shed when it comes to Fire Alarms plus, I don't have a copy of NFPA 72.

Unfortunately there are requirements in the Building Code, NFPA standards 13, 70, 72 and 101.
I get challenged pretty often with code related questions and struggle often.

I'm working on one now that is hard to put my finger on the answer. An inspector has stated that he wants smoke detectors and sprinklers below a computer room raised floor. Although I think I've got the ammunition needed, it isn't a slam dunk and always need to search through the code to find more.