Engineering notes
Dry contacts: NO or NC on the point list
On the same breaker, NO and NC reverse run/stop on the BMS. Write it before you buy the relay.
The point list says “breaker status”. The electrician takes a normally-open. The software treats closed as running — the breaker is closed, the BMS shows stop. You can invert the DDC later. Next year someone else will read the cabinet wrong.
NO and NC must match the consultant’s intent: on power loss, should the point alarm or go quiet? A full float, an open door, a dirty filter — each file picks a direction. Buy enough contacts of the right type. Do not take one SPDT and cross-wire it on site.
We write NO or NC on each line, not just “dry contact”. Interposing relays