abstract
BASIC CIRCUIT SIZING
NOEL T. FERNANDEZ, PEE, MMExM,
MMExM FIIEE
IIEEVP-Technical
A safe electrical system starts from the
very basic wiring fundamentals. In general
terms, a branch circuit could either be nonnon
motor (as in lighting, receptacle outlets, &
computers) or motor loaded circuit. The
branch circuit is the most basic component in
any electrical system, whether large or small.
A branch circuit is that part of a wiring system
extending beyond the last or final protective device to the load
loa it
specifically serves. In its simplest form, a branch circuit may consists
of two wires (single phase) or three wires (three-phase)
phase) which carry
currents at a particular voltage from the protective device to the
utilization device. The branch circuit rep
represents
resents the last step in the
transfer of power from the service or source of energy to utilization
devices. A branch circuit may have several lighting or receptacle
outlets connected to it as a circuit or may serve a single load as in
motor or heavy applia
appliance.
nce. A branch circuit will qualify as such when it
has a protective devicefrom the point of tapping.
In the course of designing, it is therefore
prudent for the engineer to train his thoughts
for the worst in situations or conditions that
may happen in the future. For instance, a group
of non-continuous
continuous loads today (requiring
smaller conductors) may no longer be the
condition after years of operation. That could
bring to a situation that the design “becomes
faulty”today while it was correct a few years
past.