There seems to be too much concern about this “static electricity” issue and I would say the discussion can cause more negative apprehension in new technicians than being simple good advice. I have been around fire alarm panels for m-a-n-n-y-y years and I never damaged a fire panel or even a fire panel component from a static electricity discharge because of a good understanding of the most misunderstood term “ground” or “grounding”.
If you have any static electricity on your body(and how did it get there?) you will discharge that static electricity safely as soon as you touch the fire panel key lock, since it is attached to the panel which is connected to the building ground, which is different from the circuit board chassis ground, which is a voltage reference point.
Once you start working on a fire panel you will only be standing and won’t create any static electricity so you have nothing to worry about.
As for capacitors, they are voltage stabilizers and since the highest DC voltage that you will see on a fire panel is 28 VDC, they present no shock hazard. Capacitors that store high voltages are for circuits entirely different than fire control panels.
There are 4 main types of “grounds”:
1 - Earth ground
2 - Chassis ground
3 - Floating ground
4 - Isolated ground
Isolated grounds are more common with UPS systems that use batteries or diesel generators and wouldn’t be our concern unless the installation of a fire alarm panel was speced with an isolating ground in conjunction with a power backup supply for the fire alarm panel that also used an isolated ground.
Each different type of ground has a specific application.
Fire alarm panels deal with #s 1, 2 and 3.
It is important that you learn the difference between the 3 uses because using a ground wire can be an important part of troubleshooting, but ONLY if you know how it affects a circuit because you will know when you CAN’T use a ground reference to troubleshoot.
Toronto, Ontario guy