Smoke Control power monitoring

[Kingswillfall]

I have to provide “positive confirmation” according to NFPA92 sec 6.4.8.2. The presence of power for a dual zone smoke control system. VFDs are housed inside with local disconnects at the fans (outside). Power monitoring must be downstream of all circuit disconnects. This means load side of the last disco and the fan motor. My dilemma is that the system is only powered when commanded by Fire Alarm input to the VFDs. How do I show status without power downstream of the disco and still meet the requirement?

 

[Jraef]

Don’t know that NFPA section, but this is what AI said it says:

NFPA 92 Section 6.4.8.2 requires that the loss of normal power to a smoke control system's dedicated power supply equipment be supervised by the fire alarm control unit
. This monitoring ensures that any failure of the primary electrical source for the smoke control system is immediately detected and reported.

Highlight added.

So to my reading, that means you just have to monitor the SOURCE, not the actual load power. So a voltage monitor relay on the switchgear/switchboard that is supplying the dedicated circuit for all of this.