Which wire is quot;hot, white or black?
Black is hot in AC voltage white is your neutral
There is no code required or generally accepted color code for fire alarm wiring. Usually circuits for different purposes are color coded differently. For instance, initiating device circuits and notification appliance circuits.
Usually, most Fire Alarm wiring is color-coded red and black. FPL and other fire alarm cables are usually red/black for a 2 conductor cable. If a system is wired class 1, with THHN conductors in conduit, I have seen both black and white used as the positive lead. The electricians who wire it are likely to use whatever convention they are used to. If they deal with low voltage, they could use white for + and black for -. If they are high voltage electricians, they could do the opposite. The AC service, (120V or 240V) will be wired per National Electrical Code (NFPA 70), which is black = line, white = neutral.
