C29.3, Wet-Process Porcelain Insulators, Spool Type;
C29.4, Wet-Process Porcelain Insulators, Strain Type;
C29.5, Wet-Process Porcelain Insulators, Low- and Medium-Voltage
C29.6, Wet-Process Porcelain Insulators, High-Voltage Pin Type;
C29.7, Wet-Process Porcelain Insulators, High-Voltage Line-Post
C29.8, Wet-Process Porcelain Insulators, Apparatus Cap and Pin
C29.9, Wet-Process Porcelain Insulators, Apparatus Post-Type.
In addition to the above, refer to the National Electrical Manufacturers
Association NEMA HV-2, Application Guide for Ceramic Suspension Insulators.
Also, refer to Fink and Beaty, Standard Handbook for Electrical Engineers.
220.127.116.11 Insulation Levels. The application of ANSI C2 requires higher
insulation levels in locations where severe lightning, high atmospheric
contamination, or other unfavorable conditions exist. This applies
particularly to areas where saltspray contamination can cause increased
operating stresses. Local practice in such areas should be checked in
determining how much increased insulation is considered necessary for
insulators and whether increased leakage distances for bushings and cable
terminations is also desirable.
install lines underground. If aerial lines are provided, insulators must be
of the radio-freed type. Provide hardware components with locknuts to avoid
loose connections, which could cause static. Locknuts must be threaded, and
of a type which will prevent loosening of the connection when wood members
Line Regulation. The voltage drop for primary lines shall not
exceed 3 percent. Maintain the power factor of the line as close to unity as
economically practical so as to minimize system losses. Regulation utilizing
load-tap-changing transformers to correct line voltage variations resulting
from changing loads or utility company sending-end voltage swings is covered
in Section 5. Requirements for line equipment follow:
Step-Voltage Regulators. Step-voltage regulators can rarely be
justified economically for new construction. They may be used on existing
construction to meet voltage drop criteria when proven to be more cost
effective than controlling the voltage drop by use of larger conductors,
provision of additional lines, or by the installation of capacitors. Refer to
Fink and Beaty, Standard Handbook for Electrical Engineers for methods of
sizing feeder voltage regulators and for regulator safety and line drop
compensation setting requirements. Single-phase regulators are preferable as
being less costly but require more installation space.