burglar / fire alarm

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mh183

Member
does a low voltage plug in transformer need a ground run if it only has two wires from transformer coming from an outlet
 

acrwc10

Master Code Professional
Location
CA
Occupation
Building inspector
What "Class" is it ? (that is a hint). There is limited energy xfmrs that are not a shock or fire hazard and don't need a ground.
 

mh183

Member
to clarify my question do you need to run a ground wire to the burglar alarm control box and must you use connectors for the wire all at 9 volts or so i am told
 

nhfire77

Senior Member
Location
NH
to clarify my question do you need to run a ground wire to the burglar alarm control box and must you use connectors for the wire all at 9 volts or so i am told

Only if the burg panel is in a metal enclosure.

Typically all burg panels require a CWP ground, not just a technical earth ground, or bonded earth ground.
 

MichaelGP3

Senior Member
Location
San Francisco bay area
Occupation
Fire Alarm Technician
Can a plug-in transformer even be used on a fire alarm panel, or a combination burglar/fire alarm panel without residing in it's own enclosure? Some manufacturers make provisions for the AC outlet to be installed on the bottom or side of the fire alarm panel; in this case the plug-in transformer resides inside the fire alarm panel.

Bosch combination panels require transformer enclosures, specifically this one:

http://products.boschsecurity.us/en/TAMS/products/bxp/SKU4.998.140.404-P3

Both these schemes insure that the janitor doesn't unplug the fire alarm when he or she needs to vacuum the carpet.
 

acrwc10

Master Code Professional
Location
CA
Occupation
Building inspector
to clarify my question do you need to run a ground wire to the burglar alarm control box and must you use connectors for the wire all at 9 volts or so i am told

As far as the question, "is it required", No. I don't see any code that would require what you are asking. It certainly wouldn't hurt any thing to ground the box, won't help, but it wouldn't hurt anything. Also you don't need connectors on the wires that are going out to the alarm contacts.
 

MichaelGP3

Senior Member
Location
San Francisco bay area
Occupation
Fire Alarm Technician
to clarify my question do you need to run a ground wire to the burglar alarm control box and must you use connectors for the wire all at 9 volts or so i am told

The "or so I am told" part throws up a flag for me.

1.) How many prongs and terminals are on the plug in transformer? 2 or 3?
2.) Do you have access to the manufacturer's instructions? What brand/model of panel are you working with?
3.) Is this in an older residence wired with K & T? If so, and you have a 3 prong plug in transformer, your question becomes more....interesting.
 

macmikeman

Senior Member
I was yawning thru the other posts, sorry about that, didn't read em all the way. If you want to have a UL compliant burg / fire panel install, then there must be a grounding path connection from the panel (and to insure said path is now code compliant may I suggest you run it to one of the code compliant locations along the service gec path to the service grounding electrode.)
 

mh183

Member
what code article would you referencing, manufacture spec show a plug in transformer and two wires going to the alarm box
 
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