Equipment & Programming or Parts and Smarts
Much of the time an Electrical Contractor will work with a Security Company in the following ways:
Electrical Contractors will install the conduit and cable for systems and often install the devices and appliances and a security company will come in later and program, test and train on those systems.
There are some EC Electrical Contractors which also hold licenses to install fire alarm and security intrusion systems. There are also some Security Companies that hold Electrical Contractor licenses so they can do high and low voltage.
Many times the Electrical Contractors that do low voltage will have special divisions that take care of the low voltage.
I do Parts and Smarts bids all the time where I provide the equipment and programming and the Electrical provides the conduit, cable, installation and we work together to get the job done.
Often an Electrical Contractor can install conduit for less money than a Security Company can.