What is an Intermediate Switch?
4-Way switch in NEC (also known as 3-way or intermediate switch in IEC following countries) is a very useful switch with four terminals (and optional ground in the US as 4-Way) and is commonly used when we need to control a light point (or any other electrical appliances like fan, alarm, in the middle of stairs etc.) from three different places. It is used with a combination of two-ways switches to control an appliance from more than two places. In addition, an electric circuit can be controlled from any number of location using intermediate switches (which is known as 3-Way in the UK and 4-Way in the US).
In an intermediate switch, there are four terminals by which it changes the flow of electric current from one circuit to another (see fig 1 & 2) and is also known as Four-Way Switch (Three Way Switch in the UK & EU). It has the ability to ON and OFF the electric supply by two ways or control the single circuit from more than two places.
The four terminals of intermediate switch construction and its operation are shown in fig below where the 4 contact points may be known as A, B, C & D. When the switch knob is up, the terminal contacts of the intermediate switch connect terminal A with Terminal C and terminal B with terminal D as shown in fig 1a. On the other hand when knob is down, terminal A is connected to terminal B and C to D then.
In other words, When the knob of the switch is UP, then the vertical contacts are connected in such a way like AC and BD as shown in fig 1a). And when the knob is DOWN, then the Horizontal contacts are connected (i.e. AB and CD as shown in fig 1b).
There is a little bit confusion about this switch due to regional codes ie. the same DPDT (double pole, double throw) switch is labeled using different names e.g.
UK & EU - IEC = It has 4 terminals for strappers wires to connect to the 2-way switches and known as Intermediate switch & 3-Way switch.
US - NEC = It has 4 terminals for travelers wires to connect to the 3-way switches and additional ground terminal known as 4-Way switch & Crossover switch.
The following fig and gif shows how is a 3-way switch or intermediate switch wired with 2-way switches (according to IEC) to control a lamp from 3 places. (Alternatively, a 4-way switch working with 3-way switches to control an LED lamp from three different locations according to NEC)
What is an Intermediate Switch?
4-Way switch in NEC (also known as 3-way or intermediate switch in IEC following countries) is a very useful switch with four terminals (and optional ground in the US as 4-Way) and is commonly used when we need to control a light point (or any other electrical appliances like fan, alarm, in the middle of stairs etc.) from three different places. It is used with a combination of two-ways switches to control an appliance from more than two places. In addition, an electric circuit can be controlled from any number of location using intermediate switches (which is known as 3-Way in the UK and 4-Way in the US).
In an intermediate switch, there are four terminals by which it changes the flow of electric current from one circuit to another (see fig 1 & 2) and is also known as Four-Way Switch (Three Way Switch in the UK & EU). It has the ability to ON and OFF the electric supply by two ways or control the single circuit from more than two places.
The four terminals of intermediate switch construction and its operation are shown in fig below where the 4 contact points may be known as A, B, C & D. When the switch knob is up, the terminal contacts of the intermediate switch connect terminal A with Terminal C and terminal B with terminal D as shown in fig 1a. On the other hand when knob is down, terminal A is connected to terminal B and C to D then.
In other words, When the knob of the switch is UP, then the vertical contacts are connected in such a way like AC and BD as shown in fig 1a). And when the knob is DOWN, then the Horizontal contacts are connected (i.e. AB and CD as shown in fig 1b).
There is a little bit confusion about this switch due to regional codes ie. the same DPDT (double pole, double throw) switch is labeled using different names e.g.
UK & EU - IEC = It has 4 terminals for strappers wires to connect to the 2-way switches and known as Intermediate switch & 3-Way switch.
US - NEC = It has 4 terminals for travelers wires to connect to the 3-way switches and additional ground terminal known as 4-Way switch & Crossover switch.
The following fig and gif shows how is a 3-way switch or intermediate switch wired with 2-way switches (according to IEC) to control a lamp from 3 places. (Alternatively, a 4-way switch working with 3-way switches to control an LED lamp from three different locations according to NEC)
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