GE Mark VIe System Manual page 137

Grounding Recommendations for Single Control Cabinet
Note If acceptable by local codes, the bonding jumpers may be removed and a 4/0 AWG identified insulated wire run from
FE to the nearest accessible point on the building ground system, or to another ground point as required by the local code.
The grounding method for a larger system is displayed in the following figure. The FE is still connected to the control
electronics section, but the equipment-grounding conductor is connected to the center cabinet chassis. Individual control and
I/O bases are connected with bolted plates.
For armored cables, the armor is an additional current carrying braid that surrounds the internal conductors. This type cable
can be used to carry control signals between buildings. The armor carries secondary lightning-induced earth currents,
bypassing the control wiring, thus avoiding damage or disturbance to the control system. At the cable ends and at any
strategic places between, the armor is grounded to the building ground through the structure of the building with a 360°
mechanical and electrical fitting. The armor is normally terminated at the entry point to a metal building or machine.
Attention to detail in installing armored cables can significantly reduce induced lightning surges in control wiring.
Installation Guidelines GEH-6721_Vol_I_BP System Guide 137
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