Primus Wind Power AIR 40 User Manual

28 AIR Owner’s Manual
Turbine Grounding
Proper grounding of the AIR wind turbine protects people and equipment by
eliminating dangerous voltage potentials.
The following section describes tower grounding in detail. To ground the
AIR body, connect the ground (green) conductor to the tower ground
rod. Alternately the ground (green) conductor may be connected to the
negative (black) conductor in which case it will be grounded through the
battery bank ground rod. Refer to Figs. 8 -11.
Note that all system grounds should be connected using conductors of the
same size as the positive and negative wires.
If you choose to not set up an earth ground system (not required for
systems under 50 volts), the green and black conductors MUST be
connected to each other or severe damage to the turbine may result and
void your warranty.
Primus Wind Power strongly recommends that boat installations be grounded
according to American Boat and Yacht Council recommendations. There are
special grounding requirements for boats, in particular boats that connect to
shore AC power, that MUST be observed or a serious shock hazard may result.
Contact the American Boat and Yacht Council at +1 410.990.4460 or at www.
abyc.com.
Tower Grounding (Fig. 16)
Every wind turbine and tower should be grounded at the tower base even
if the turbine is grounded at the battery bank or service panel by means of
the yaw ground lead.
The following sections are a guide and should not be considered
comprehensive. Reference the National Electrical Code (NEC) and local
building and zoning regulations for complete requirements. Relevant
sections of the National Electrical Code are referenced.
Electrodes Driven in Soil
Electrodes must be a minimum of 8 ft (2.5 m) in length and free of non-
conductive coatings such as paint. Hollow (pipe or conduit) electrodes
must not be smaller than trade size 3/4 (metric designator 21) and must
be galvanized or otherwise protected from corrosion. Solid rod electrodes
must be at least 5/8 inch (16 mm) diameter. Stainless steel rods less than
5/8 inch diameter, nonferrous rods or their equivalent less than 1/2 inch
diameter shall be “listed” by an organization having jurisdiction in the area.
For example: UL in the USA and CSA in Canada.
Electrodes shall be installed such that 8 ft (2.5 m) is in contact with the
soil. They should be driven into undisturbed soil within 1 ft of the tower
foundation. If rock is encountered the electrode may be driven at an angle
not to exceed 45 degrees from vertical. Some local authorities permit burial
of the electrode in a trench at least 30 inches (76 cm) deep.
The upper end of the electrode including the grounding conductor should
be below grade. If above ground it must be protected from damage.
Bonding the grounding conductor to the electrode and to the tower may
be accomplished by exothermic weld or by a “listed” mechanical connector.
Solder connections are not permitted. Most local authorities require a
minimum grounding conductor size of 6 AWG for copper and 4 AWG for
aluminum (if aluminum is permitted).
The grounding conductor may be buried directly or contained in conduit. It
is important to have no sharp bends to keep its inductance low.