Specification MIL-V-176, Varnish, Moisture and Fungus Resistant (for Treatment
of Communication, Electronics and Associated Equipment). Circuit elements
Circuit Elements (High Temperature Rise). Do not coat circuit
similar electrical components, which have a temperature rise exceeding 75
degrees F when operating at full load, with a fungitoxic compound. Instead,
give such components two coats of varnish and one sealer coat. Apply the
coats by the vacupressure, immersion, centrifugal or pulsating-pressure, or
built-up method so as to fill all interstices in the coils and preclude the
entrapment of air or moisture. The sealer coat may be applied by brushing or
Ferrous Items. Where steel is necessary as a base material, use
material which is galvanized, plated, or cladded. Use stainless steel where
applicable, with type specified to provide for mechanical, structural and non-
corrosive characteristics. Clear epoxy coatings and metallized coatings
provide satisfactory additional corrosion protection.
Ambient Temperature. Give due consideration to high ambient
temperatures when specifying and sizing electrical equipment. Derating of
components is necessary where normal operating temperatures exceed 86
degrees F, such as rooftop installations and the interiors of protective
enclosures. Derate outdoor transformers in accordance with ANSI temperature
loading guides. Precautions such as ventilation fans may be necessary to
assure reliable operation with long service life.
Wiring Systems. The climatic conditions in most tropical areas are
such that all non-enclosed locations are classified as "wet" locations as
defined by the National Fire Protection Association, Inc. (NFPA) No. 70,
National Electrical Code (NEC).
Design raceway systems in accordance with
Conduits and Fittings. On piers and in other hostile environments
where galvanized steel conduits are normally specified, use PVC-jacketed
galvanized steel conduits and fittings. Other documents which form a part of
the specification for the plastic coated galvanized steel rigid conduits and
fittings are American National Standards Institute Inc. (ANSI) Standard C80.1,
Specification for Rigid Steel Conduit. Zinc Coated, and Underwriters'
Laboratories Inc., (UL)-6, Conduit Electrical. Rigid Metal.
Enclosures and Boxes. Ferrous metal enclosures and boxes exposed
to salt-laden air provide service for only a few years. Use cast copper-free
aluminum or PVC outlet bodies or boxes in lieu of cast ferrous metal. In very