How to Replace a Switch

How to Replace a Switch

Over time, the light switch may need to be replaced due to wear, contamination, or breakage. It is considered good practice to replace the electrical switchgear before selling the property, so that all electrical equipment meets modern requirements and standards. In addition, modern switches may have additional functions, such as smooth or touch off.

Steps for replacement switch

You will need no more than 30 minutes and the minimum set of tools that can be found in every home.

1. Prepare the necessary tools and materials

To install a new or replace an old switch, you will need:

  • switch;
  • knife;
  • voltage indicator;
  • flat and Phillips screwdrivers.

2. Turn off the electricity

All work with electrical wiring should be carried out in a de-energized room.

To do this, turn off the main switch on the electrical panel in the apartment or on the landing. Move the machine knobs down: the icons should change from red to green or from one to zero.

Click the switch in the apartment and make sure that there is really no voltage in the network.

3. Disassemble the old switch

If you do not change the switch, but install a new one, go to the next step.

For old and modern machines, the disassembly procedure is slightly different. For Soviet-style products, the procedure is as follows:

  • Unscrew the screws on the decorative panel with a screwdriver.
  • Carefully pry off the cover and remove it.
  • Loosen the screws of the mounting brackets and remove the mechanism from the wall.
  • Do not disconnect wires yet.

For modern switches, the decorative panel is mounted on latches or screws that are hidden under the keys. Therefore, proceed differently:

  • Gently pry the keys with a flat screwdriver and remove them.
  • Loosen the screws or bend the tabs of the latches along the edges of the switch and remove the decorative cover.
  • Loosen the spacers and remove the fixing screws on the metal frame, if any.
  • Without disconnecting the wires, remove the switch from the wall.

3. Count the wires

The number of cores can be judged by the number of keys, but sometimes there are exceptions. Therefore, it is better to make sure that the required number of wires are laid in the wall. It will depend on which switch you can install.

Take a close look at the mechanism. Count how many wires are connected to it, and find out if there are any idle wires in the wall. In total there can be from two to four.

  • Two wires – suitable for single-key switch. It is possible to control one or all lamps of an individual luminaire.
  • Three wires – suitable for a two-gang switch. It is possible to control two lamp groups one  pole of t ry  or two separate lamps.
  • Three wires – also three cores are needed for passage switches. It is possible to control one or all lamps of a single lamp from two different places.
  • Four wires – suitable for a three-key switch. You can control three groups of lamps of one chandelier or three separate lamps.

4. Turn on the electricity

This is necessary to pinpoint the incoming phase wire on the switch.

To activate the current, move the handle of the machine in the electrical panel to the upper position. The indicator icons will change from green to red or from zero to one.

5. Determine the phase

Take the voltage indicator and alternately touch each of the wires coming to the switch. On one of them, the indicator LED should light up – this will be the phase wire. Remember its color or mark with a marker or a piece of electrical tape.

6. Turn off the electricity

Go to the electrical panel and turn off the main machine by moving its handles down, as described in the second paragraph.

7. Remove the old switch

If you do not change the device, but install a new one, proceed to the next step.

It remains only to loosen the clamping screws of the contacts with a screwdriver in order to pull out the wires and remove the old switch.

8. Strip the wires

For reliable contact with cable cores, it is necessary to remove 5–10 millimeters of insulation with a knife. Strip wires along, not across. Take care not to accidentally damage them.

9. Reconnect the new switch

Difficult, at first glance, the task is quite simple and consists in the correct connection of wires according to the scheme. For single-key, multi-key and walk-through switches, there are differences, but the principle is one.

It is necessary to connect the phase wire, which we marked in the fifth paragraph, to the corresponding contact of the switch. Usually it is indicated by the letter L, less often by the number 1 or the symbol of an arrow directed inward of the mechanism.

Outgoing phases or, as they are also called, control wires are connected to the remaining contacts. They are designated by the symbols L1, L2, L3, or simply 1, 2, 3. In some cases, arrows pointing outward from the switch are used as marking.

Most often, the incoming and outgoing phases are located on opposite sides of the device. However, there is a design when all the contacts are on one side.

How to connect a switch with one key

  • Insert stripped wire cores into the terminal clamps. On the single-key switch, they may not be marked, since this is not important here.
  • Tighten the clamping screws well for a secure fit and good contact.

How to connect a switch with several keys

  • Insert the incoming phase wire, which we marked in the fifth paragraph, into the terminal marked L.
  • Insert the remaining cores into the remaining clamps with the marks L1, L2, L3 (1, 2, 3 or outgoing arrows).
  • Tighten the clamping screws firmly to secure the wires.

How to connect a passage switch

  • Install the phase conductor marked in the fifth paragraph into the terminal labeled L or the incoming arrow.
  • Insert the remaining cores into the clamps with the symbols of the outgoing arrows or the numbers 1 and 2.
  • Tighten all clamping screws with a screwdriver for a secure fit.
  • Repeat the procedure for the second switch.

10. Fasten the switch to the wall

  • Fold the wires with an accordion and place the switch in the mounting box.
  • Align the mechanism and secure it by tightening the spacer screws.
  • Secure the switch with the fixing screws on the metal strip, if any.
  • Snap the decorative cover into place.
  • Put on the keys and lock them with your finger.

11. Turn on the electricity

Apply voltage by turning on the switch in the electrical panel. If everything is done correctly, the installed switch will work properly.

Tips for replacement switch

  • In old houses, sometimes there is no grounding. Some switches with motion detection do not work without grounding.
  • If the switch does not work, you may have made a mistake with the wiring diagram. In this case, you will have to call an electrician. While waiting for an electrician, keep the switch off and do not touch it.
  • Install the switch yourself only if you are absolutely confident in your skills. Incorrect installation of the circuit breaker can be dangerous!
  • Do not forget to supply electricity to the switch after installation.
  • Consider installing continuously adjustable switches or a motion sensor for safety and energy savings.
  • If the switch does not fit in the wall, try trimming and reinstalling the wires a little.
  • Even if you have completely de-energized the room, handle the wires carefully. It is better to check for current in the wires twice
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