Emergency Lighting Insalation Standard - Diagram Query

[Mazdaman]

Hi, while reading Standard NZS 2293.1:2018 I saw 2 switch symbols for a Sub-circuit sensing Device (highlighted in blue) that are not identical. Feel free to heap scorn but I don't know what the right hand switch / contact represents.



Regarding a suitable sensor device have others used the Clevertronics Automatic testing unit with 12 circuit sensingAutomatic testing unit with 12 circuit sensing OK? https://www.scottelectrical.co.nz/catal ... -operated/

Thank you.

[Mazdaman]

Normally closed contacts, when the test button is pressed 'K'' open these these 2 contacts and EM lights come on for testing, it looks like the R/H contact may be a misprint.

looking at the clevertromics unit, it looks like it monitors several circuits and if you loose a circuit (breaker trips) then this activates the EM lights.

There are variations on this by different manufactures, legrand (HPM) does something similar. you can also get em lights that talk to each other via wireless comms and to a base station and automatic testing and report on health status can be done.

[AlecK]

Agree they are n/c contacts.
But (being pedantic) when test button is pressed, they will not be opening, but closing (else the E-lights would be switched 'off" instead of "on")
The convention for schematic drawings is that "normal" means de-energised; rather than whatever state may be perceived as normal once placed in service.
As drawn, the contacts are in normal / de-energised state (so the E-lights are "on").
When all sensing circuits are energised, the unit will open these contacts.

I have no idea what the extra bit on the right contact is; have not seen it before. May be a misprint.