If the concern is bonding of the bollards for static control, NFPA 77 addresses this. Here is an excerpt on bonding and grounding that may help.
7.4.1 Bonding and Grounding. Bonding is used to minimize
the potential difference between conductive objects, even where
the resulting system is not grounded. Grounding (i.e., earthing),
on the other hand, equalizes the potential difference between
the objects and the earth. Examples of bonding and grounding
are illustrated in Figure 7.4.1.
7.4.1.1 A conductive object can be grounded by a direct conductive
path to earth or by bonding it to another conductive
object that is already connected to the ground. Some objects are
inherently bonded or inherently grounded because of their contact
with the ground. Examples of inherently grounded objects
are underground metal piping and large metal storage tanks resting
on the ground.
7.4.1.2 The total resistance between a grounded object and
the soil is the sum of the individual resistances of the ground
wire, its connectors, other conductive materials along the intended
grounding path, and the resistance of the ground electrode
(i.e., ground rod) to the soil. Most of the resistance in a
ground connection exists between the ground electrode and
the soil. This ground resistance is quite variable because it
depends on the area of contact, the resistivity of the soil, and
the amount of moisture present in the soil.
7.4.1.3 To prevent the accumulation of static electricity in conductive
equipment, the total resistance of the ground path to
earth should be sufficient to dissipate charges that are otherwise
likely to be present. Aresistance of 1 megohm (10E6 ohms) or less
generally is considered adequate.
7.4.1.3.1 Where the bonding/grounding system is all metal,
resistance in continuous ground paths typically is less than
10 ohms. Such systems include those having multiple components.
Greater resistance usually indicates that the metal path is
not continuous, usually because of loose connections or corrosion.
A grounding system that is acceptable for power circuits or
for lightning protection is more than adequate for a static electricity
grounding system.
7.4.1.3.2 Annex G contains diagrams of various grounding
devices, connections, and equipment.
7.4.1.4 Where wire conductors are used, the minimum size of
the bonding or grounding wire is dictated by mechanical
strength, not by its current-carrying capacity. Stranded or
braided wires should be used for bonding wires that will be
connected and disconnected frequently. (See Annex G for additional
information.)
7.4.1.5 Grounding conductors can be insulated (e.g., a jacketed
or plastic-coated cable) or uninsulated (i.e., bare conductors).
Uninsulated conductors should be used because defects are
easier to detect.
7.4.1.6 Permanent bonding or grounding connections can
be made by brazing or welding. Temporary connections can
be made using bolts, pressure-type ground clamps, or other
special clamps. Pressure-type clamps should have sufficient
pressure to penetrate any protective coating, rust, or spilled
material to ensure contact with the base metal.