How to Wire 3-Phase Simultaneous Water Heater Thermostat?
Three Phase Continues Unbalanced Dual Element Electric Water Heater Thermostat Wiring
In our popular electric water heater wiring installation series, we will show three phase unbalanced and simultaneous electric heater thermostats and heating element wiring (480V and 415V AC) in today post.
Difference Between 3 Phase Balanced and Unbalanced Water Heater
- Balanced 3 Phase Water Heater:
In balanced three phase wiring, all the hot wires (lines) carry equal supply (same magnitude of current and voltage). In case of star connection, the neutral carry zero current acting as a return path for current.
- Unbalanced 3 Phase Water Heater:
In this wiring, a single hot wire (line) provides supply to both heating elements through heater thermostat. The sum total of neutral point is not zero i.e. it carries the net unbalanced current.
3-Phase Unbalanced Simultaneous Water Heater Thermostat Wiring
Simultaneous or continuous means both the upper and lower thermostats and heating elements are operational at the same time and doesn’t depends on each other as separate three phase supply has been provided to each heating element.
Keep in mind that both the lower and upper thermostats are ECO-protected i.e. both are same. In this wiring connection, the Line 1 (Red) is connected to the L1 and L3 terminals of upper and lower thermostats respectively. Line 2 (Yellow) and Line 3 (Black) are connected to the L3 of upper thermostat and L1 of lower thermostat respectively.
Upper heating element is connected through L4 and T2 terminals of upper thermostat and lower heating element is connected through L4 and T2 terminals of lower thermostat.
This way, both heating elements are operational at the same time. The same wiring diagram can be used for three phase 480V AC (US – NEC) or any other three phase supply and 3-Phase 415 V AC (UK & EU – IEC). Note that we have used red, black and blue for three phase hot lines for illustration purpose only. You may follow your regional electrical codes and wiring colors.
Related Posts:
- How to Wire 120V Simultaneous Water Heater Thermostat?
- How to Wire 120V Non-Simultaneous Water Heater Thermostat?
Wire and Breaker Size for Three Phase Electric Heaters
In our wiring tutorial, we have used 6 gauge wire for each hot wire. You may use the appropriate cable / wire and circuit breaker according to the heater rating. Check the user manual and nameplate data printed on thermostat and heating elements.
| Element Wattage | Phases | Circuit Breaker Size (Amp) | Copper Wire Size in Gauge | ||||||
| 208V | 240V | 277V | 480V | 208V | 240V | 277V | 480V | ||
| 3000W | 1 | 20 A | 20 A | 15 A | 15 A | 12 | 12 | 14 | 14 |
| 3 | 20 A | 20 A | – | 15 A | 12 | 12 | – | 14 | |
| 3800W | 1 | 25 A | 20 A | – | – | 10 | 10 | – | – |
| – | – | – | – | – | – | – | – | – | |
| 4000W | 1 | 25 A | 25 A | 20 A | 15 A | 10 | 10 | 12 | 14 |
| 3 | 25 A | 25 A | – | 15 A | 10 | 10 | – | 14 | |
| 4500W | 1 | 30 A | 25 A | 25 A | 15 A | 10 | 10 | 10 | 14 |
| 3 | 30 A | 25 A | – | 15 A | 10 | 10 | – | 14 | |
| 5000W | 1 | 30 A | 30 A | 25 A | 15 A | 10 | 10 | 10 | 14 |
| 3 | 30 A | 30 A | – | 15 A | 10 | 10 | – | 14 | |
| 5500W | 1 | 35 A | 30 A | 25 A | 15 A | 8 | 10 | 10 | 14 |
| 3 | 35 A | 30 A | – | 15 A | 8 | 10 | – | 14 | |
| 6000W | 1 | 40 A | 35 A | 30 A | 20 A | 8 | 8 | 10 | 12 |
| 3 | 35 A | 30 A | – | 15 A | 8 | 10 | – | 14 | |
| 8000W | 1 | 50 A | 45 A | 40 A | 25 A | 8 | 8 | 8 | 10 |
| 3 | 45 A | 40 A | – | 20 A | 8 | 8 | – | 12 | |
| 9000W | 1 | – | 50 A | 45 A | 25 A | – | 8 | 8 | 10 |
| 3 | 50 A | 45 A | – | 25 A | 8 | 8 | – | 10 | |
| 10000W | 1 | – | – | 50 A | 30 A | – | – | 8 | 10 |
| 3 | – | 50 A | – | 25 A | – | 8 | – | 10 | |
| 11000W | 1 | – | – | 50 A | 30 A | – | – | 8 | 10 |
| 3 | – | 50 A | – | 25 A | – | 8 | – | 10 | |
| 12000W | 1 | – | – | – | 35 A | – | – | – | 8 |
| 3 | – | – | – | 30 A | – | – | – | 10 | |
Three Phase Wiring Color Codes – NEC & IEC
NEC:
Three Phase 480 AC:
Black = Phase 1 or Line 1, Red = Line 2, Blue = Line 3, White / Gray = Neutral and Green/Yellow = Earth Conductor
IEC:
Three Phase 415 AC:
Grey = Phase 1 or Line 1, Black = Line 2, Brown = Line 3, Blue = Neutral and Green = Earth Conductor
Related Posts:
- How to Wire Non-Simultaneous 240V Water Heater Thermostat?
- How to Wire 240V Simultaneous Water Heater Thermostat?
Related Wiring Installation Tutorials:
- Single Phase Electrical Wiring Installation in Home – NEC & IEC
- Three Phase Electrical Wiring Installation in Home – NEC & IEC
- How to Wire Auto & Manual Changeover & Transfer Switch – (1 & 3 Phase)
- How to Connect a Portable Generator to the Home Supply – 4 Methods
- How to Wire Analog and IP PTZ Camera with DVR and NVR?
- How to Wire Different Fire Alarm Systems – Conventional & Addressable
- Even More Residential Wiring Installation Tutorials
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