A kill-switch is a separate electrical AC switch to be used for cutting off the electrical power that is consumed by a device. This is convenient for reducing stand-by electricity consumption and for manually switching devices. In most cases, a luminous switch is being applied.

This instructable explains how to modify a kill-switch in such a way that the indicator light in the luminous switch is disabled.

The niche applications for the kill-switch without an indicator light can be found in the area of atmospheric lighting, for switching devices where an indicator light is disturbing and for switching devices with relatively low electricity consumption and relatively long times being active, such as a charger for a mobile device.

Power consumption measurements in this instructable show that the electricity consumption of an indicator light is really low (approximately 0.17 W for a single kill-switch). Consequently, the maximum electricity consumption is 1.5 kWh per year, resulting in expenses ranging from 0.20 to 0.40 euro annually (0.25 to 0.50 US$ per year). However, as the purpose of a kill-switch usually is to switch things off, the typical energy consumption for most users will be less.

This instructable shows how the indicator light can be disabled by interrupting a single connection, by simply cutting the right internal wire. Three hacking alternatives are being presented:

1. The safest way: removing the entire internal cable;
2. The reversible approach: cutting the cable and electrically insulating it against short-circuiting. This allows to reconnect the wire and to restore the original functionality of the luminous switch;
3. Kill-switch de luxe: adding an additional switch that allows putting on or off the indicator light as desired.

Important: first read the safety instructions introduced in the next step.

For info: openproducts is offering kill-switches with disabled indicator lights through the webshop, see https://www.instructables.com/member/openproducts. This only regards CEE 7/4 AC power plugs and sockets (Schuko), which is, among others, common in a number of European countries.

The concept described in this instructable is being made available through a Creative Commons BY license, see Step 9 for additional info.

Step 1: Safety Issues

A kill-switch is meant to be operated at 230 V AC or other voltage levels depending on national circumstances. In itself, 230 V is dangerous. Make sure not to touch bare cables. Never operate the kill-switch without having properly closed it. If in doubt, consult an expert.

Important note for usage: an adapted kill-switch might mislead users when the indicator light is off while the power actually is on. Therefore, instruct all users and clearly mention on the switch that the indicator light has been disabled.

Step 2: Application and Use: Niche Markets for This Adapted Device

A kill-switch is a separate electrical switch (often integrated into a switch socket) that can be used for cutting off the electrical power that is consumed by a device. This is convenient for two purposes:

1. To stop the stand-by electricity consumption when a device is turned off;
2. To be able to manually switch devices that don't have their own on/off button.

This instructable describes a niche market for using a kill-switch without a luminous switch: those applications in which:

1. It is desirable to manually switch a device for purposes as stated in points 1 and 2 above, and
2. You don't want to see the indicator light in the kill-switch.

This instructable explains how to modify a kill-switch in such a way that the indicator light in the luminous switch is disabled.

The niche applications for the kill-switch without an indicator light can be found in four areas:

1. Switching of devices for atmospheric lighting: a floor-lamp or a table lamp that doesn't have its own on/off switch and for which the power plug and thus the indicator light is annoyingly visible;
2. Switching video devices close to the television screen to reduce stand-by electricity consumption while the device is not in use. When the device is playing it is often desirable to not see the indicator light;
3. For switching devices with relatively low electricity consumption and relatively long times being active. An example might be the charger of a mobile device: the indicator light is not needed and might be disturbing, especially in a room with atmospheric lighting.
4. Any other application where it is simply enough to see whether the switch is on ('I') of off ('O') as indicated by its symbols.

An additional argument might be the electricity consumption from the indicator light, but indicative measurements in this instructable (see next step) show that the power consumption is really low (approximately 0.17 W for a single kill-switch).

Step 3: Measuring the Power Consumption of a Kill-switch

The AC power measuring device that has been used for this experiment has a measuring range from 1.5 W to 3000 W. A single kill-switch is below the lower threshold, therefore twelve luminous switches in parallel were measured. Then the cumulative power amounted to 2.0 to 2.1 W, resulting in an average power consumption of 0.17 W per kill-switch.

Consequently, when active continuously, the maximum electricity consumption is 1.5 kWh per year, resulting in a cost ranging from 0.20 to 0.40 euro annually (0.25 to 0.50 US$). However, as the purpose of a kill-switch usually is to switch things off, the typical energy consumption for most users will be less.

Step 4: The Plan

The electrical layout of a kill switch is very simple. Usually, only one of the two wires connecting the front to the back is being interrupted. In order to light up the luminous switch a connection is made to the other pole. Note that the indicator light is connected after the switch (where a device can be plugged in) .

This instructable shows how the indicator light can be disabled by interrupting a single connection, by cutting the right internal wire. Three alternatives are being presented:

1. The safest way: removing the entire internal cable (alternative 1, see step 6);
2. The reversible approach: cutting the cable and electrically insulating it against short-circuiting. This allows to reconnect the wire and to restore the original functionality of the luminous switch (alternative 2, see step 7);
3. Kill-switch de luxe: adding an additional switch that allows putting on or off the indicator light as desired (alternative 3, see step 8).

The electrical circuit explains the layout for the three cases above.

The following steps show how this as been done.

Step 5: Opening the Kill-switch

For opening the kill switch unscrew the screws at the backside. If you're lucky this doesn't require any special screwdriver. Else, you'll need special tools. Safety warning: never operate the kill-switch without having it properly closed.

Step 6: Alternative 1 - Removing the Entire Internal Cable

Based on the electric diagram (see step 4) it should be possible to locate the cable that needs to be interrupted for putting out the indicator light in the switch. Remove the cable completely: this is a safe way to avoid short-circuiting.

Close the kill-switch and make sure to inform the users of the adapted kill-switch that the luminous switch will always be off, regardless of its state.

Step 7: Alternative 2 - the Reversible Approach

Locate the cable that needs to be interrupted based on the electric diagram (see step 4). Cut the cable in a position that allows to reconnect it in a later stage. Make sure that both cable ends are properly insulated against short-circuiting, for example by using a flexible tube. The inside space of the kill-switch should be sufficient for using a connector to safely restore the circuit.

Make sure to inform all users of the adapted kill-switch that the luminous switch will always be off.

Step 8: Alternative 3 - Kill-switch De Luxe

Cut the cable that needs to be interrupted based on the electric diagram (see step 4). Instead of insulating both wires, connect them to an additional switch that allows putting on or off the indicator light. Make a hole in the casing of the kill-switch to situate the auxiliary switch. Note that this operation will impact your kill-switch considerably and also that this action cannot be undone. Warranty will expire (this is also the case for alternatives 1 (step 6) and 2 (step 7) by the way).

After finishing make sure to inform all possible users of the kill-switch about its new functionality.

Step 9: License and Sales

The concept described in this instructable is made available through a Creative Commons Attribution license (CC BY, http://creativecommons.org/licenses/by/3.0).

Openproducts is offering kill-switches with disabled indicator lights through the webshop, see https://www.instructables.com/member/openproducts. This only regards CEE 7/4 AC power plugs and sockets (Schuko), which is, among others, common in a number of European countries. The kill-switch is adapted according to the description of 'alternative 1' in step 6. Note that if you buy a hacked kill-switch you'll will need to inform all users about the disabled indicator light for safety reasons, see also step 1.

Openproducts would be happy to see other parties to trade and sell the adapted kill-switches (for example those other than CEE 7/4 plugs) as introduced in this instructable, provided that the design is attributed to openproducts, preferably with reference to this instructable. For other arrangements send a Private Message through the instructables member page (https://www.instructables.com/member/openproducts)

If this design infringes any rights then refer to Article 28 in the Terms of Service (https://www.instructables.com/tos.html).