Chapter hvac engineering Fundamentals: Part 1 Introduction

12.12
National Electric Code
The bible of the electrical portion of the construction industry is the
National Electric Code
(NEC), also cataloged as NFPA 70.
2
This vol-
ume is given the weight of law in most parts of the United States. It
defines in great detail what does and does not comprise an acceptable
electrical installation. This volume is of interest to HVAC designers
in several ways.
1. It defines required ventilation (natural or forced) for several types
of areas housing electrical gear.
2. It prohibits spatial intrusions of unrelated ducts and piping into
electrical rooms.
3. It defines acceptable electrical assemblies for many HVAC units
which have electric components.
While the NEC is relatively coherent at face value, it sometimes
becomes onerous in the local interpretation. Some jurisdictions pro-
hibit any piping in an electrical room, yet fail to accommodate other-
wise required roof drain lines or wet sprinkler fire protection. Heating
Electrical Features of HVAC Systems
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