Induction cooktop, with its many advantages and functionalities, does have some requirements to function correctly. The foremost requirement being the power supply
The electric installation must comply with all applicable electrical codes and should be properly earthed (grounded).
The only reason why you are pondering over this question (does the cooktop need phase 3 power) can be that either you are in the design phase of your home or doing a major renovation in your kitchen or replacing electrical units in your kitchen.
Induction cooktops usually work on single phase 220-240 V AC, 50-60 Hz. the amp requirement can be 20AMPS, 30AMPS ( for 60 cm induction), 32 AMPS ( for 76cm induction) , 42 or 48 AMPS ( for 81-91 cm induction). Most American households are connected as a single phase.
The only reason to go three-phase is when you have lots of high powered domestic appliances like a lot of AC, many cooktops or some high-end induction cooktops which may require electric requirements at least 400V.
These will have to be hard-wired by a licensed electrician.
The three-phase power gives 380-415V AC, 50Hz. The amp requirement for 60cm cooktop being 16AMPS, 76cm induction being 16AMPS and 86-91cms also being 16 AMPS.
Almost all induction cooktops today are made to be compatible with the common standard voltage supply. So they are rated mostly 120V, or between 200-240V.
In many places in the United States, the voltage requirements are 120V. In such cases, don’t worry you can still use a cooktop rated 230V by installing a three-wire phase split wiring.
Induction equipment comes in two basic types:
Cooktops that meant to be built as a permanent part of the kitchen. In case of which the wiring done will be permanent. And the other type is countertop units intended to be portable which can be plugged into an electrical socket.
Phase converters are used when three-phase equipment needs to be operated on a single-phase power source. They are used when three-phase power is not available or the cost is high.
Explaining the electrical requirements in simple terms
Electricity, as you know, is a flow of energy. Let us compare it with the flow of water to help analyze it. Water flows in a pipe under the influence of force or pressure generated somewhere up the line. Similarly, electricity flows in a wire under the influence of a force called the e.m.f. The generation of e.m.f is done by your power company just as the water pressure is generated and supplied to homes.
The e.m.f is called as ‘Voltage’ and it is measured in units called volts.
So the greater the pressure (voltage), the more energy it will carry, the more work it can do.
Now just like flowing water, while the force is important, so is the actual flow of water acting under that force. For example, a gushing thick river can get more work done than a tiny gushing creek falling that same distance. So the volume of the flow acting under pressure is important and that is called as current and measured as ampere. Amp is a flow measure in other words.
Electrical power is measured with a unit called watt. In places where we are using a lot of watts, we often use KILOWATT which is 1000 watts. It is basically the rate at which electrical energy is being used or delivered. One watt is a current of one amp flowing under the “pressure” of one volt.
To know how much energy is being used or delivered, we have to multiply by time ( for example two gallons of water per minute for three minutes delivers 6 gallons of water).
The measure of energy is joules, more commonly called as kilowatt-hour. So kilowatt-hour is the energy conveyed by a flow of one kilowatt running for one hour.
Wiring suiting induction
Water does not flow in the pipes without the need to overcome resistance. Or else the tiniest pressure would send the water in any direction.
It is restricted by the thickness of the pipe, internal roughness of the pipe, bends in the pipe. Likewise, electricity does not flow unimpeded in wires.
Some materials carry the electricity with little opposition and some with great opposition or resistance. The energy current loses in overcoming this resistance is given off as heat.
Even though the electricity carrying wires in your home walls are excellent conductors of heat, they are not without resistance.
So the size of the wire is rigidly set by the building laws and codes to match the maximum amount of current that size is allowed by law to carry. This ensures that no in-wall wire ever gets hot enough to be a fire risk. So the wire is sized for a certain maximum current or looking it the other way the maximum current is set by the size of the installed wire.
The law also requires that there be a device that will instantly break (open or switch off the circuit) if the allowed maximum is ever exceeded.
In the olden times that device was a fuse that was designed to switch off at the maximum current, it is rated for. Nowadays a more common term is the circuit breaker.
Taking it back to the induction cooktop
The point here is that the power supply to your kitchen cooking unit does not have an infinite capacity. You need to restrict yourself to the induction cooking unit that does not demand more than your wiring can supply.
If you are in the designing stage of your home, you need to install wiring adequate to the induction cooktop unit you want.
Typically the voltages in American homes is 240 volts and the induction cooktop you purchase lets you know its power requirements. This way you can calculate the required AMPS for your in-wall wiring.
For example, if you want a four-element induction each having a maximum power of 1.8KW. The power output would be 4* 1.8= 7.2KW. That would require an AMPS of 7200/240= 30 AMPS.
Older homes in the USA had 150amps main house panels. This meant that the entire house could take no more than 150amps from the power company. Newer homes are built with 200 amps service.
The building codes mostly specify 20amp, 240 V service for dedicated appliance circuits. If you want higher AMPS then you need thicker wires.
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