How to connect a three-point pass-through switch

In long hallways or corridors, a pass-through switch is often installed - the 3-point connection scheme ensures the equivalence of the electrical circuit sections. The user can press any key from which the lighting will turn on or off.

Design and features of pass-through switches

The external pass-through device does not differ from the standard one. The difference can be seen only when looking at the product from below - manufacturers put triangles on the case, directed horizontally downward.

The second variant of the difference is 3 terminals with copper contacts. One is at the top and two at the bottom. Also, the pass-through device is switched through a three-core VVG-ng or NYM cable with a cross section of 1.5 mm2.

Depending on the number of buttons, there are two-key, one-key and three-key modifications.

In comparison with classic two-pole models, you need to connect the bushing according to the following principle:

• serial connection of switches;
• the phase does not open, but switches to the second line;
• there are more output contacts than input contacts.

The paired poles of the switches are located opposite each other.

Nuances of choice

Before buying a pass-through switch, consider:

• Mounting method - depends on the type of wiring. Overheads are installed on the surface using self-tapping dowels. Built-in - in socket outlets with spacer legs.
• Degree of protection - for a bedroom or corridor, models with IP03 are suitable, for a bathroom - with IP04- IP05, for outdoor - with IP55.
• Type of contact clamps. Screw with pressure plates are reliable. Screwless spring-loaded ones are easier in terms of installation.
• Terminal Marking - N (zero), L (phase) and earth (ground) designations are used. The letters I and O mark the position of the buttons when switching on and off.

According to the type of control, pass-throughs are keyboard, touch, with a remote control.

Application of the scheme

Pass-through models are designed for the convenience of supplying or removing voltage to lighting fixtures from different ends of the room. Most often, this scheme is used:

• In a long corridor with exits from different rooms. At the exit, put one switch, in the middle - the second, at the end - the third.
• In the courtyards of country and private houses, dachas. Switching devices are mounted at the exit from the house and outbuildings.
• In multi-apartment three-storey buildings. The device is placed on the ground floor to enable the switch-on. You can turn off the lighting on the second and third floors.
• In the children's room with several beds. The solution provides for one device at the entrance and two next to the sleeping berths.
• Stairways and cottage grounds outside the city. One device is mounted at the beginning of the staircase; shutdown is carried out from the second floor or near the attic.

With the help of a pass-through switch, energy savings are ensured.

Connection of a pass-through switch from 3 places

To connect a circuit with three devices for each point, you will need its own switch that implements lighting control.The circuit of a pass-through switch from three places provides for the installation of a pass-through switch with 4 contacts in the center. The end nodes will work at two points, depending on the position of the penetrator. The light will not light up at different positions of the two extreme switches.

The loop-through device will redirect the phase from the contact at the top of the input switch to the lower contact of the output:

1. The buttons are directed downwards - the lighting is not active. Press the switch number 1 - the phase is directed along the circuit along one line, the light comes on.
2. Extinguishing light from switch No. 2. The button is pushed up. Opening of the line occurs, there is no phase at the input.
3. Switch button # 3 is at the top. The circuit is closed, the lighting comes on. To disable it, you need to change the position of the switch.

The peculiarity of this circuit is that all actions are performed only with the end of the phase, which prevents a short circuit. The installation of the system is carried out from the distribution box or by direct connection of commutation cables.

Direct connection will help save wire.

What is needed to complete the task

When performing electrical work with your own hands, it is worth purchasing:

• junction box;
• Light source;
• 2 pass-through switches;
• 1 cross switch;
• 3 socket boxes;
• cable with 2, 3 and 4 cores;
• self-clamping terminal blocks;
• marker;
• colored electrical tape or heat shrink.

To accomplish the task, you will need side cutters, screwdrivers, a knife for stripping the insulation from the cores, a multimeter, and a gating device.

Cross-disconnector principle

A cross switch is often used for a 3-point lighting connection. It looks like a one-key device externally, but there are 4 terminals inside. A cross device is called because it switches two power lines.

The disconnector provides a one-time disconnection of switches No. 1 and No. 2. The connection of the nodes is also carried out synchronously. The light comes on and off as the contacts move.

When organizing a larger number of points, the process of connecting parts inside the junction box becomes more complicated.

Installation work

Lighting systems are installed according to the following algorithm:

1. Search for a common terminal point on the bushing.
2. Connection to the first breaker next to the phase junction box.
3. Fixing the phase to the common terminal with an orange or red cable.
4. Connection at the output internal terminals of the pass-through device of the 2 remaining conductors.
5. Throwing wires and fasteners on the second switch according to the color marker.
6. Connection inside the box of the orange / red conductor from the switch No. 2 to the phase of the lamp.
7. Connection inside the switch box according to the color coding of 2 free wires per core of switch No. 1.

At the end, neutral and ground are connected inside the box to similar wires to the lighting device.

Two-key

To control the operation of light sources from two points, a two-key pass-through with 6 contacts is used. The installation of the pass-through switch is as follows:

1. Shared contacts detection.
2. Feeding the phase wire to the input of switches No. 1 and No. 2.
3. Connect the rest of the inputs with a switch to the ends of lamps No. 1 and No. 2.
4. Connecting the free ends of the lamps to the neutral cable.
5. Throwing 2 outputs of the switch No. 1 to the outputs of the switch No. 2.
6. Similar fastening of the remaining outputs.

When using two two-key switches, the length of the wires increases.

Three-key

A three-key device is similar in connection type to a two-key device. The difference is that you need to add a fourth wire. One cable feeds the phase to the breaker, three cables go to the load. Installation is carried out as follows:

1. Find the terminals for connecting the phase conductors on the side parts of the contact block.
2. Connect the phase cable No. 1 from the side of one terminal.
3. Connect the remaining three phase wires to three terminals.
4. Phase 1 is brought into the switch box and connected to the cable wire leading to the switch.
5. At the input, the phase is connected to the lower input contact.
6. From the three output contacts of the switch at the top, three phase cables are diverted into the distribution box and connected to the wires leading to the ceiling.
7. On the ceiling, the phase wires are thrown onto the terminals of the luminaires.

The neutral must be brought into the junction box and connected to a wire directed towards the ceiling. There, zero must be connected to the blue point of the terminals of the luminaires to form a common terminal.

Connection errors

When self-switching, novice electricians and home craftsmen often make a number of mistakes:

1. Incorrect phase-to-zero connection. The feed-through switch breaks only the phase. An incorrect circuit without affecting the wiring of the pass-through switch controlled from 3 places is corrected by re-connecting the wires in the junction box.
2. Violation of the sequence of phase and zero. The problem is signaled by switches that are inoperative in one position.
3. The two-key is installed correctly, but does not work. By mistake, a standard switch was purchased, which, if there is a receipt, will be replaced in the store.
4. Connecting the line to a wire with the wrong cross-section. The fourth core of the cable has a diameter that is 1/3 smaller than the others. It is not connected to the phase, but only to the ground loop.
5. Parallel connection. When organizing intermediate control, only a sequential circuit with the passage of the same phase is used.

If the connection rules are violated, there are risks of electric shocks when replacing the light bulb, a short circuit of the switch may occur. The wiring also burns out and the bushing breaks.

Disadvantages of pass-through switches

The organization of a power line with a pass-through switch has several disadvantages:

• the time and effort spent on chipping the wall with hidden wiring;
• the need to connect the remote control via a regular key for models with motion sensors;
• unprofitable for an apartment due to cable gates and din-rail installation;
• Difficulty defining terminals
• lack of clarity of the positions "ON" and "OFF".

Experts note that the devices are more suitable for country cottages, summer cottages, the private sector than for an apartment.

The pass-through switch is convenient to use in rooms with several groups of lighting fixtures. The device provides the comfort of light control, the safety of people moving. At present, the scheme of a pass-through light switch, controlled from three places, is not tied to the layout of a residential building.