Low Voltage is mentioned many times in the Philippine Electrical Code (PEC). However, the PEC failed to explicitly include Low Voltage in the definition of terms. The purpose of the PEC, being a statutory document, is the practical safeguarding of persons and property from hazards arising from the use of electricity (see Section 1.0.1.1(a)).

What design basis will then be used by a Filipino Electrical Engineer tasks to do electrical design "Low Voltage Systems" for the selection of electrical equipment ratings?

In Section 1.10.3.5 (c), it is mentioned that

Where the voltage exceeds 600 volts, nominal, permanent and conspicuous warning signs shall be provided, reading as follows:
DANGER — HIGH VOLTAGE — KEEP OUT

Based on the above-mentioned section of the PEC, does it mean that electrical systems rated 600 volts or less are low voltage? The clause will lead to conflicting interpretation of a low voltage system.

In Section 1.1, the term "Nominal Voltage" was defined as

Voltage, Nominal.
A nominal value assigned to a circuit or system for the purpose of conveniently designating its voltage class (e.g., 120/240 volts, 480Y/277 volts, 600 volts). The actual voltage at which a circuit operates can vary from the nominal within a range that permits satisfactory operation of equipment.

FPN: See ANSI C84.1-1995, Voltage Ratings for Electric Power Systems and Equipment (60 Hz).

The FPN refers to a North American Standard ANSI C84.1. This standard defines several voltages classes

ANSI C84.1-2011 Electric Power Systems and Equipment — Voltage Ratings (60 Hertz)

3 System voltage classes
3.1 Low Voltage (LV): A class of nominal system voltages 1000 volts or less.
3.2 Medium Voltage (MV): A class of nominal system voltages greater than 1000 volts and less than 100 kV.
3.3 High Voltage (HV): A class of nominal system voltages equal to or greater than 100 kV and equal to or less than 230 kV.
3.4 Extra-High Voltage (EHV): A class of nominal system voltages greater than 230 kV but less than 1000 kV.
3.5 Ultra-High Voltage (UHV): A class of nominal system voltages equal to or greater than 1000 kV.

The Fine Print Note under the definition of switchgear states that

FPN: All switchgear subject to PEC 1 requirements is metal enclosed. Switchgear rated below 1000 \I or less may be identified as "low-voltage power circuit breaker switchgear." Switchgear rated over 1000 V may be identified as "metal enclosed switchgear" or "metal-clad switchgear." Switchgear is available in non-arc-resistant or arc-resistant constructions.

This section of PEC 1 again provides different criteria of low-voltage from what had been previously mentioned above.

In your opinion, WHAT IS REALLY LOW VOLTAGE AS PROVIDED FOR BY THE PHILIPPINES ELECTRICAL CODE?

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