Fire Alarm Annuciator Panel Grounding

[jes25]

Hi guys,

I have a FA annuciator that is being added to the current scope of work. I recieved the Simplex-Grinnel LCD unit and it says the back box must be hooked to a "dedicated earth ground per article 250" It also says this is to arrest transients or something along those lines. There is no line power in the unit. Does anyone know what code they are referring to? I'm not to sure what they mean by "earth ground", but I was planning on just taking a wire up to the building steel.

Thanks in advance

 

[gadfly56]

Hi guys,

I have a FA annuciator that is being added to the current scope of work. I recieved the Simplex-Grinnel LCD unit and it says the back box must be hooked to a "dedicated earth ground per article 250" It also says this is to arrest transients or something along those lines. There is no line power in the unit. Does anyone know what code they are referring to? I'm not to sure what they mean by "earth ground", but I was planning on just taking a wire up to the building steel.

Thanks in advance

The annunciator will have four (4) conductors; two (2) for 24vdc power and two (2) for the data line.

The building steel should do just fine.

 

[jes25]

The annunciator will have four (4) conductors; two (2) for 24vdc power and two (2) for the data line.

Yup

The building steel should do just fine.

Any tips on how to actually do this? You can't run smaller than a #6 GEC with out protection, but it seems kinda silly to run a 6 for this little panel. I'd opt for the 6 over the pipe for protection however.

 

[gadfly56]

Yup



Any tips on how to actually do this? You can't run smaller than a #6 GEC with out protection, but it seems kinda silly to run a 6 for this little panel. I'd opt for the 6 over the pipe for protection however.

Alas, as an engineer I usually just tell people they have to make it happen while being a little short on the "how". Any chance of running the EGC inside a wall until you get to steel? Actually, since the annunciator is a power limited device, Chapter 3 wiring methods don't apply unless specifically stated otherwise. You also may not be able to run anything larger than #12; most of the terminals for FA panels/devices aren't listed for larger sizes.