Elevator shunt trip power monitoring

[bgelectric]

Ive noticed alot of times drawings do not include this in them. Its specifically an nfpa 72 requirement. Does anyone know if there are exceptions to this rule?
I often have to bring it up because its not included which makes me wonder if there is some sort of exception.

 

[GrayHair]

From where I stand ...

From where I stand ...

My guess is that it's the human condition:

Most people change not because they see the light, but because they feel the heat.
​

When one of my installs failed an inspection, you can bet I never failed another for that reason. Maybe it had been pointed out and I read it in the code, but just didn't remember it. If I had to dig it out of the code on my own, I darn sure remembered it.

Or nobody will take responsibility.

Regards!

 

[ron]

Can you post the NFPA 72 section where this is required?

 

[bgelectric]

Can you post the NFPA 72 section where this is required?

NFPA 72 2007
6.16.4.4
Control circuits to shut down elevator power shall be monitored for the presence of
operating voltage. Loss of voltage to the control circuit for the disconnecting means shall
cause a supervisory signal to be indicated at the control unit and required remote
annunciators.

 

[ron]

NFPA 72 2007
6.16.4.4
Control circuits to shut down elevator power shall be monitored for the presence of
operating voltage. Loss of voltage to the control circuit for the disconnecting means shall
cause a supervisory signal to be indicated at the control unit and required remote
annunciators.

Thanks
I use a fire alarm control module to provide the operating voltage to the shunt trip. The control module is monitored for trouble, like other fire alarm devices and will cause a supervisory signal to be indicated if failed.

 

[ryant35]

Every elevator (with shunt trip) I have worked on had shunt trip power supervision using an isolation relay dry contacts and a N/O fire alarm point.

 

[iwire]

Every elevator (with shunt trip) I have worked on had shunt trip power supervision using an isolation relay dry contacts and a N/O fire alarm point.

Never see it here.

 

[bgelectric]

Never see it here.

Which is why I ask, its pretty obvious that its a code requirement yet often times i do not see it on engineered drawings.

 

[gadfly56]

Thanks
I use a fire alarm control module to provide the operating voltage to the shunt trip. The control module is monitored for trouble, like other fire alarm devices and will cause a supervisory signal to be indicated if failed.

If I understand correctly, however, your module won't know when the external power source fails, unless you are using an intelligent control module with power supplied by the FACP like the Siemens HCP or ICP.

 

[haydenjsle]

.......its pretty obvious that its a code requirement yet often times i do not see it on engineered drawings.

There are no exceptions to this requirement.....its often missed by the fire alarm engineer due to lack of knowledge. When it is incorporated, its often programmed or wired wrong to initiate a trouble condition, instead of a supervisory condition.:?

The best way to accomplish IMO is via a normally energized isolation relay mounted adjacent to the shunt trip control relay. The coil on the isolation relay is paralled with the shunt trip external power source and the NO dry contacts on the isolation relay are then monitored as a supervisory type input by the FACP. Mount both within 3 feet of the shunt trip breaker. Three NFPA 72 codes are met this way--shunt trip power supervision, relay supervision, and location of relays that are providing a fire safety function.:thumbsup: