Frequently asked questions about Elektrobock regulators and switches

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Common questions about controls and switches from Elektrobock – a complete guide

Elektrobock is a long-established Czech manufacturer of switching and control components, whose products have been installed in homes and small businesses in Slovakia for decades. Despite this – or perhaps precisely because of it – the same questions keep arising during sales and after installation. A customer buys a timer switch under a switch, finds at home that there may not be a neutral conductor in the box, or is unsure how to program multi-day cycles. Someone else wants to control a garden pump wirelessly and doesn't know whether a remote-controlled socket is sufficient or if a different power class is needed.

In this article, we have gathered the truly most frequently asked questions from practical experience – from installation details through power limits to compatibility and programming – and answer them with technical accuracy that you won't find in a shortened manual.

Basic product classification of Elektrobock: what you are actually buying

Before we get into specific questions, it is useful to briefly understand what Elektrobock offers in the category of controls and switches. The products are divided into several logical groups:

Timer switches under the switch (CS3 series) – installed directly into the box under a standard switch frame, they replace a classic button or switch while preserving the standard appearance of the installation.
Timer switches for DIN rail (CS4 series and others) – intended for switchboards, suitable for higher power and more complex installations.
Wireless and remote-controlled components – for example, the remote-controlled socket WS101, which does not require any installation into the electrical network and functions as a plug adapter.
Room thermostats – temperature controllers with various levels of sophistication, from simple bimetallic to weekly digital programmers.

Each group has different installation requirements, a different power limit, and a different programming method. Confusing these groups is the most common source of misunderstandings.

Installation and mounting: what you need to know before purchasing

Does a timer switch under a switch require a neutral conductor?

This is by far the most common question and also the most common reason for returning the product. The CS3 series includes several variants precisely because not all installations have a neutral conductor (N) available in the box under the switch.

Timer switch CS3-1 and CS3-1B do not require a neutral conductor – they are powered by a small current passing through the load (so-called load-powered supply). This is an advantage in older installations where only a phase conductor and a switched output lead into the box. The disadvantage is that with very low resistive loads (e.g., LED lighting with very low power), there may be minor issues – slight flickering, irregular switching off. In practice, it holds: if the load is at least 5–10 W of resistive type, it works reliably.

CS3-2 and CS3-4 require a neutral conductor in the box, but in return, they are more power-stable and better handle capacitive and inductive loads. If you have a newer installation (usually yes after the year 2000) or you are unsure, have an electrician check what conductors lead into the box.

Practical tip from practice: If you have a box with three conductors (L, N, switched output), use CS3-2 or CS3-4 – installation is simpler and the device works more reliably with any type of load.

What dimensions does the box required for CS3 have?

The CS3 series is designed for standard installation boxes with a diameter of 60 mm and a minimum depth of 40 mm. Most modern boxes in Slovak households meet this condition. Problems arise in older apartments (panel buildings from the 70s–80s), where you may encounter boxes only 35 mm deep. A switch physically does not fit into such a box.

The solution is to replace the box with a deeper one – a relatively simple intervention for an electrician – or to choose a more compact model (CS3-1 is slightly flatter than CS3-4 with a larger display). We always recommend measuring the depth of the box before purchase.

Can I install the switch myself, or do I need an electrician?

From a legal perspective: the installation of electrical equipment in a 230 V network requires an expert with the appropriate authorization according to Ordinance No. 508/2009 Coll. in Slovakia. In practice, for standard consumer installations (single-family house, apartment), this means that an authorized person can also be a home handyman with an electrical education (§21 – instructed person, §22 – experienced person). If you do not have this education, leave the installation to an electrician.

From a technical perspective: if you know how to work with electrical installations, the procedure is relatively simple and we describe it in detail in the article Installation of the timer switch under the switch CS3: step-by-step procedure in this Knowledge Center. Always disconnect the circuit breaker before starting work and verify the absence of voltage.

Programming: weekly programs, switching times and special functions

How many switching times can I program?

It depends on the model:

CS3-1 and CS3-1B: basic model with one channel, typically 8–16 switching times per day, possibility of different settings for workdays and weekends.
CS3-2: two channels, each with its own independent program – suitable for controlling two lighting circuits or lighting + socket circuit from one box.
CS3-4: up to 4 independent channels, maximum number of programs – this model is intended for more complex applications (multiple lighting scenes, combined regulation).

A detailed procedure for setting up a weekly program can be found in the article Programming a weekly switching program on Elektrobock switches. Here is a brief summary: most models work with a minimum step of 1 minute and allow combining daily programs – that is, setting a different program for Monday–Friday, Saturday and Sunday.

What happens during a power outage – will I lose the program?

The CS3 series uses non-volatile memory (EEPROM or Flash), where the programmed times are stored permanently. The program therefore will not be lost during a power outage. What will be lost or disrupted is the current time and date – after power is restored, you usually have to set the clock again.

Some models have a backup battery (CR2032 or similar), which keeps the clock running even during a power outage. Check the specifications of the specific model – if the battery is missing or depleted, after a longer power outage, the clock will reset to 00:00 and the switch will start switching according to the stored program, but from an incorrect time reference point.

Practical tip: After installation, always write down the set program – in case of a service reset or device replacement.

Power and load compatibility

What is the maximum power the CS3 switch can handle?

This is the second most common question and also the area where the most frequent mistakes are made. Switches under the switch are designed for loads in the range of 5 W to 2,000 W (2 kW) for resistive loads (light bulbs, heating elements). Capacitive loads (LED drivers, electronic transformers) and inductive loads (motors, transformers) have a significantly lower maximum allowable power.

Resistive load (R): max. 2,000 W / 10 A
Inductive load (L): max. 1,000 W / 4–5 A (depends on the model)
Capacitive / LED / electronic load (C): max. 200–500 W (always check the datasheet of the specific model)

A more detailed overview can be found in the article What is the maximum power a timer switch or Elektrobock socket can handle. In practice: if you want to control an entire lighting circuit with LED lights (typically 20–60 W total power), most CS3 models can handle it. If you want to control an electric water heater of 2 kW, the load is at the limit and we recommend using a DIN rail switch with a larger contactor instead.

Do CS3 switches work with LED lights?

Yes, but with certain reservations. The main problems with LED loads are two:

Minimum load: Models CS3-1 and CS3-1B powered through the load require a minimum load consumption typically 5–10 W. With modern LED panels with a consumption of 3–4 W, there may be a problem with flickering or unstable switching.
Surge current (inrush current): LED drivers and switching power supplies have a short surge current pulse at turn-on, which can be several times higher than the rated current. For the relay in the switch, this means increased contact wear.

In practice: for normal use (controlling 5–10 LED bulbs or panels with a total consumption of over 15 W), CS3 switches work reliably for years without problems. For very low loads (one LED bulb of 5 W), a model with a neutral wire (CS3-2, CS3-4) is more reliable.

Wireless socket WS101 – what it is and what it is not

Wireless socket WS101 is a solution for situations where you do not want or cannot interfere with the fixed electrical installation. You plug it into a standard 230 V socket and connect an appliance to it. It is wirelessly controlled by a radio signal (typically 433 MHz) using an attached remote control.

The advantage is zero installation effort – no electrician, no drilling. The disadvantage is that it is a switching socket without a time program – it only reacts to manual commands from the remote control. If you want automatic switching according to time, you must use one of the CS3 models mounted in the wall, or a socket timer of another type.

The maximum power of the WS101 is 3,500 W / 16 A, which is sufficient for most common appliances including water immersion heaters (2–3 kW). For details on pairing with a controller, see the article Remotely Controlled Socket WS101: Setup and Pairing with a Controller.

Malfunctions and diagnostics: when something doesn't work

Switch doesn't turn on at all – what to check first?

From practical experience, we know that most reported faults are not actual device defects, but errors in setup or installation. Proceed as follows:

Check whether the switch has power – the display should be lit or blinking.
Check whether the current time displayed is correct. If not, set it first.
Verify that at least one switching time is programmed and active for the current day.
Try a manual start (override function) – most models allow manual switching of the output regardless of the program.
Check whether the load (e.g., a light) works when connected directly without the switch.

If the switch still doesn't turn on after these steps, it is likely a hardware defect. Further diagnostic procedures can be found in the article Common faults of Elektrobock timers and their solutions.

Load flickers although it is turned off – why?

This is a classic symptom of a model without a neutral wire (CS3-1, CS3-1B) combined with a load that is too low in resistance. A parasitic current flowing through the internal circuits of the switch can cause weak lighting or flickering of LED lamps.

Solutions:

Use a model with a neutral wire (CS3-2 or CS3-4) – if a neutral wire is available in the box.
Connect a resistor (typically 15–47 kΩ / 1 W) in parallel to the LED load to ensure a minimum draw required to power the switch. This solution is less elegant, but functional.
Replace LED lamps with types that have a higher draw or with types that better suppress residual current.

Compatibility between models and system expansion

Can I control multiple sockets or lights with one controller?

Yes, in the case of the wireless system (WS101), this is a standard feature. One controller button can be paired with multiple sockets simultaneously – just pair each socket to the same button during pairing. For example, you can turn on the living room and hallway lights with one press.

In the case of a fixed installation (CS3 series), this does not work directly – each switch functions as an independent unit. If you want to control multiple lighting circuits from one location, either use a multi-channel model CS3-2 or CS3-4, or consider a DIN rail with a central programmable relay.

Are CS3 switches compatible with all frames and covers?

The CS3 series is designed to fit under a standard 45×45 mm frame (Schuko, or alternatively Legrand, ABB Basic 55, Schneider Unica, etc.). After mounting in the box, the switch is covered with the supplied cover or a standard frame of compatible dimensions. The switch protrudes from the box by about 10–12 mm more than a standard switch, which is not a problem for most frames.

Exceptions may be design frames with very flat covers (e.g., some Berker, Jung or Gira series) – in these cases, we recommend checking directly, or using the cover supplied by Elektrobock.

Are CS3 switches suitable for use in wet areas (bathroom, exterior)?

No. The CS3 series has an IP20 rating (indoor use, dry interior). Installation in a bathroom is only possible under the conditions of ČSN/STN 33 2000-7-701 – zones 2 and 3 require at least IP44. For outdoor use, you need at least IP44, ideally IP65. Elektrobock has other series for outdoor use, but the CS3 series is not suitable for these conditions.

Special features and less known options

What is the "random" function and when is it useful?

Several Elektrobock models (including some variants of CS3) support so-called random mode. In this mode, the set on/off time is shifted by ±15–30 minutes randomly, so the switching does not look mechanical and regular. This function is useful for simulating presence in a home during a holiday – the lights do not turn on exactly every day at 17:30, which would be noticeable to a potential thief.

Can I set the switch to respond to a button press (override)?

Yes. All models of the CS3 series allow manual override of the program. Usually, a short press of the button on the device toggles the output to the opposite state (if it is off, it turns it on and vice versa), and the device remains in this state until the next scheduled change in the program. Some models also have so-called permanent manual mode (bypass), where the program is completely ignored and the device responds only to manual control – useful for example during a party, when you want the lights to stay on all night regardless of the program.

How long will the device last without failure?

Elektrobock states the relay has a minimum lifetime of 100,000 switching cycles. With typical use (2 switching cycles per day), this corresponds to more than 130 years, so the relay is not a weak link. Weaker links in practice are the display (in models with backlighting), buttons, and in less favorable environments, the electronics itself due to voltage fluctuations. From practice: well installed and not mounted in environments with large temperature changes or voltage surges, these switches typically function for 10–15 years without service intervention.

Comparison of CS3 series models at a glance

Model	Neutral wire	Channels	Max. power (R)	Typical use
CS3-1	NO	1	2,000 W	Old installations without N, lighting, fans
CS3-1B	NO	1	2,000 W	Same as CS3-1, version B with extended settings
CS3-2	YES	2	2,000 W	New installations, LED, two independent circuits
CS3-4	YES	4	2,000 W	Complex scenes, multiple circuits, professionals

Typical scenarios from practice: how customers use these switches

Garden lighting: A common job – the customer has a 150 W garden light (halogen or LED reflector) and wants it to turn on automatically at dusk and off at midnight. We install CS3-1 into an existing box without a neutral wire, set one program: ON 20:00, OFF 00:00. We adjust the times seasonally once a month. It works for years without problems.

Automatic bathroom ventilation: The customer has a fan in the bathroom and wants it to turn on in the morning and evening for 30 minutes, not manually. We install CS3-1 or CS3-2 instead of a regular fan switch, set 2 programs per day. Fan power is typically 15–30 W – no problem at all.

Heating for a winter garden: A more demanding case – the customer has an electric heater of 1,500 W in the winter garden and wants it to preheat in the morning before work. Here, CS3 can handle the load (1,500 W is under the 2,000 W limit), but we recommend checking that the load conductor has a cross-section of at least 1.5 mm² and the fuse is properly dimensioned. If the heater were 2,000 W, we would rather use a DIN rail with a larger relay – not because CS3 can't handle it, but for safety margin.

Wireless control of a garden pump: The customer has a 400 W submersible pump for irrigation and doesn't want to run control wires. WS101 – a socket in an IP44 outdoor socket protected from rain, an adapter plugged into it, and the pump into the adapter. Control from the terrace with a remote control over 30 meters through the wall – no problem.

Most frequently asked questions (FAQ)

Can I use CS3-1 to control LED lights without a neutral wire?

Yes, but it depends on the load power. For a total LED load above 10–15 W, CS3-1 works reliably. For very low loads (one 5 W LED bulb), flickering or unstable switching may occur due to the fact that the switch is powered by a parasitic current through the load. A solution is to switch to CS3-2 (if you have a neutral wire), or to connect a small resistor in parallel to the load.

Where can I find out if there is a neutral wire in my box?

A neutral wire (N) is present in the box if three wires lead into it: phase (L, usually brown or black), neutral (N, blue), and switched output (usually black or gray). If you have only two wires (phase and switched output), there is no neutral in the box – in that case, choose CS3-1 or CS3-1B. In any case of doubt, have an electrician check the box condition.

Is it possible to program the CS3 switch from a mobile phone or via an app?

No. The CS3 series is purely locally controlled – programming is done directly on the device using buttons and the display. These switches have no WiFi, Bluetooth, or connection to smart home systems. If you require remote control or programming via an app, you need to choose another product line (e.g., Shelly, Sonoff, or similar smart relays). The CS3 series is designed as a reliable, simple, and cost-effective solution without dependence on the internet or a smartphone.

Can one remote control (DO) pair with multiple WS101 sockets?

Yes. One remote button can control multiple WS101 sockets simultaneously – just switch each socket to pairing mode and press the same remote button. This way, you can, for example, turn on lights in multiple rooms with one button. One remote typically has 4–6 separate buttons, allowing you to create several device groups.

What to do if I forget the password or reset procedure for CS3?

The CS3 series does not use passwords – programming is always accessible directly via the buttons on the device. If you want to reset the switch to factory settings, it usually suffices to hold two buttons simultaneously for 5–10 seconds (the exact procedure depends on the model, you can find it in the manual). After the reset, all programmed times and settings, including the current time, are deleted – you need to enter everything from the beginning.

Can I use CS3-2 or CS3-4 instead of a regular staircase switch?

Not directly. A staircase switch requires a special wiring (interlocking wiring with two or more switches), where CS3 is not a direct replacement. CS3 switches only one circuit according to the program and does not have an input for a second button at the other end of the stairs. On stairs, it is common to combine CS3 with a classic impulse relay or system switches. If you need manual control from multiple locations plus automatic switching, a combination of CS3 + staircase automation is a functional and cost-effective solution.

Conclusion: how to choose the right product

The Elektrobock CS3 switch series is a proven and robust technology that reliably serves for years without any maintenance when chosen and installed correctly. The key to satisfaction is answering three questions before purchase: Is there a neutral wire in the box? What power (and what type of load) do I want to switch? How many independent channels do I need?

If you are unsure about the type of your installation, it is always worth spending 15 minutes with an electrician rather than later dealing with product returns or inexplicable flickering lights. For situations where you do not require time-based automation but only convenient remote control, the remotely controlled socket WS101 is an ideal solution with no installation effort at all.

For a deeper look at choosing a specific model, we recommend the article How to choose the right Elektrobock timer for your home and for comparing installation formats the article Wall-mounted timer vs. DIN rail-mounted: which type to choose. If you are considering self-installation, a detailed step-by-step guide can be found in the article Installation of a wall-mounted timer CS3: step-by-step guide.

Do you have a question on this topic?

Having trouble deciding or dealing with a specific situation in your home? Write to us – we are happy to help.