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How to Wire 600/347V 3ΦY, 1-Phase & 3-Phase Load Center

Electrical Technology
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Wiring a 600/347V, Single & Three Phase Main Breaker Box for Commercial Applications

What is 347 & 600V Commercial Supply?

The 600/347V commercial supply is a common three-phase, four-wire (3-Φ, 4W) electrical power system commonly used in Canada and some older installations in the US for medium to large commercial and industrial applications.

It is a grounded system with three hot conductors and a neutral conductor, connected in a wye configuration from the secondary of a utility transformer.

The Star (Y or Wye) connected 600/347V main panel or load center for power distribution offers the following levels of voltages:

  • 347V Single Phase, 3 Wires (One Hot wire + Neutral wire + Ground wire)
  • 600V Single Phase, 2 Wires (Two out of phase Hot wires + Ground wire)
  • 600V Three Phase, 4-5 Wires (Three out of phase Hot wires + Neutral wire (if needed) + Ground wire)

347V & 600V - Wye - 1 & 3-Phase Supply

Good to Know: 600/347V system is similar to 480/277V systems used in the United States, but Canada uses 600/347V as its standard for many commercial installations.

This voltage system is mainly used in commercial, industrial, and large building applications in Canada for commercial buildings, industrial facilities. It is mainly used three-phase machinery rated for 600V such as, HVAC units, pumps, motors, elevators, and large commercial appliances rated for 600V. The 347V single phase supply is used for lighting circuits which is efficient for commercial fluorescent or LED lighting.

Good to Know:

Why 600/347V is Beneficial than 277/480?

Compared to the 277/480V system used in the United States, Canada uses a 600/347V system in industrial and large commercial facilities that require high-wattage applications. To keep the current (amps) low, higher distribution voltage is used. This approach reduces conductor size requirements and helps save costs on feeders and cables.

Voltage Levels in 347/600V Panel

In a 600/347V three-phase wye (Y) system, the voltage relationships are based on the following formulas

VL-L = √3 × VL-N

600V ≈ 1.732 × 347V

Hence:

  • Line-to-Line (or Phase to Phase) voltage (VL-L) = 600V
  • Line-to-Neutral (or Phase to Neutral) voltage (VL-N) = 347V

Based on this type of “wye” (or “star”) electrical service provides three different voltage levels, depending on how the circuit is connected:

  • Voltage between Phase and Neutral = 600V / √3 = 347V (1-Φ).
  • Voltage between two hots (Phases) = 600V (1-Φ).
  • Voltage between three hots (Phases) = 347V × √3 = 600V (3-Φ).

347V Single Phase = It is the line-to-neutral voltage and measured between any one of the three hot phases and the neutral wire. This is commonly used for high-efficiency commercial lighting and smaller single-phase loads.

600V Single Phase: It is the line-to-line voltage, measured between any two of the three hot phases. This voltage system is rarely used in specific applications.

600V Three Phase: It is the line-to-line voltage, measured between three hot phases. This higher voltage is used to power larger three-phase equipment such as motors, pumps, and HVAC systems.

In simple words, the available voltage levels in a 347V and 600V, 1-Phase & 3-Phase main service panel are as follows:

  • Voltage between three hot wires (hot 1, hot 2 & hot 3) = 600V, 3-Phase
  • Voltage between any two hot wires = 600V, 1-Phase
  • Voltage between any hot wire and Neutral = 347V, 1-Phase

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How to Wire 347/600V, 1-Phase & 3-Phase Commercial Main Panel

Now, Let’s see how to wire 600V and 347V, single phase and three phase breakers and load circuits in the breaker box as follows.

Wiring 347V, 1-Phase Circuits using 1-P Breakers

The following tutorial explains how to wire a 347V single-phase circuit derived from a 600V three-phase commercial supply.

A 347V single-phase voltage is obtained between any one hot conductor (Hot 1, Hot 2, or Hot 3) and the Neutral. For example, in the figure below, a 347V-rated UFO LED parking-lot light is connected to a single-pole breaker. The 1-pole breaker and its associated 347V outlet are connected to Hot 2, Neutral, and Ground.

You may use a 347V single-phase NEMA locking receptacle, such as NEMA L24-20. This is a 2-pole, 3-wire grounded receptacle that requires three conductors e.g., one hot conductor from the breaker, plus the neutral and the equipment grounding conductor (EGC) from the neutral/ground busbar in the main panel.

Wiring 600V, 1-Phase Circuits using 2-P Breakers

The 600V single phase between any two HOT lines is rarely used. If 600V, 1-phase is needed, a double-pole breaker rated for 600V can be used between any two lines. As an example load, 600V, 1-Φ industrial heater is connected between Hot 1 and Hot 2 using 2-pole breaker rated for 600V.

The following NEMA locking outlets rated up to 600V can be wired between two hots for 600V – single phase.

  • NEMA L9-20, L9-30, L9-50, L9-60 – (2-pole, 3-wire) grounding – No Neutral – rated for 600V

Similarly, 600V single phase loads such as resistive and reactive load banks, HV air heaters, transformers (to get 120/240V supply) are used in 347/600V panel via 2-pole breakers in commercial applications.

Wiring 600V, 3-Phase Circuits using 3-P Breakers

For 600V, three phase circuits, we need four or five wires (Three Hots + Neutral (if needed) + Ground. As shown in the following fig, three phase motor is connected through three hot wires + ground wire using the three-pole 600V breaker.

The three-phase NEMA locking outlets rated for 600V with gerund and neutral wires (if required), are also wired the same way using 3-pole breaker rated for 600V as follows:

  • NEMA L13-30 for three phase (3-pole, 3 wire) non-grounding – No neutral
  • NEMA L17-30, L17-50, L17-60 (3-pole, 4 wire) grounding – No neutral
  • NEMA L20-20, NEMA L20-30  (4-pole, 4-wire) with neutral – non-grounding
  • NEMA L23-20, L23-30, L23-50, L23-60  (4-pole, 5-wire) groaning with neutral

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Wiring of 347V/600V, 1-Phase & 3-Phase Breakers and Load Circuit

 

Wiring Color Codes for 347V & 600V

For 347V & 600V service, the following wiring color codes are used based on Canadian Electrical Code (CEC).

  • Red = Hot 1 or Line 1
  • Black = Hot 2 or Line 2
  • Blue = Hot 3 or Line 3
  •  White = Neutral Wire
  • Green or Green with   Yellow  stripes = Bare Conductor as Ground wire (EGC)

Good to Know:

  • Green, green/yellow, or bare conductors must never be used for any wire that carries voltage. These colors are reserved exclusively for equipment grounding conductors (EGC).
  • Only and only use copper wire to reduce the resistance and heat instead of aluminum wires in the main panel box wiring.
  • The terms Hot, Phase, and Line all refer to the same thing i.e. conductors that carry live voltage
  • Never touch the main lugs (terminal screws) located before the main breaker, as they remain continuously live and carry high voltage even when the main breaker is switched OFF.

Instructions & Precautions

Warning:

  • Never attempt to work with electricity without proper knowledge, supervision, and safety precautions. Electrical work should be performed in the presence of experienced professionals who understand safe working practices.
  • DIY electrical work can be dangerous and may also be illegal. Consult a licensed electrician or your local electrical power provider before making any changes or modifications to electrical wiring systems.
  • Disclaimer: The author is not responsible for any losses, injuries, or damages resulting from the use or misuse of this information, or from improper implementation of any circuit. Please exercise extreme caution as electricity is hazardous and can be fatal.

Resources:

Related Main Panels Wiring Tutorials

Sizing Breakers, Wires, and Panels

Standard Breakers & GFCI Breakers Wiring Installations

General Outlets and GFCI/AFCI Receptacles Wiring

Switches Wiring

Finding the Number of Breakers/Outlets in a Circuit

General Wiring Installation Tutorials:

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Electrical Technology
0 8 minutes read

Electrical Technology

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