Why can a system have three hours of autonomy while some cables are rated E30?
The emergency operating duration of the energy source and the period for which a cable or enclosure must maintain its function during fire are different design requirements. The handbook discusses a 30-minute functional-integrity requirement in certain German and Austrian guidelines. Project-specific obligations must be checked separately.
How many luminaires can be connected to one central-battery circuit?
The handbook refers to a maximum of 20 luminaires per circuit under a provision of HRN HD 60364-5-56. Verify the relevant standard clause, circuit design and manufacturer instructions for the actual installation.
What is a mixed circuit?
A mixed circuit combines maintained and non-maintained emergency luminaires within a compatible central power architecture. The design must support both modes and the appropriate fault monitoring.
How often must emergency lighting be maintained?
Inspection, testing and maintenance are ongoing obligations. The source refers to HRN EN 50172 and HRN EN 62034; exact schedules must be taken from the applicable standards and equipment documentation.
When should the emergency lighting switch on?
The system must activate automatically when the supply to the normal lighting fails, subject to its intended operating mode and required response characteristics.
Why use supercapacitors?
Supercapacitors may provide a long cycle life, rapid charging and good performance over a broad temperature range. Their lower energy density means they are not suitable for every required operating duration.
Are automotive starter batteries suitable for a CPS system?
Only batteries that comply with the relevant requirements and are specifically approved for the application should be used. A conventional starter battery must not be treated as a drop-in replacement for a certified stationary safety power supply.
FAQ, NOTES AND REFERENCES
FREQUENTLY ASKED QUESTIONS (FAQ)
Q: If battery autonomy is three hours, why are the fire-resistant cable and central unit classified E30?
A: In Germany, MLAR and, in Austria, OVE E 8101 specify that functional integrity of the room must be maintained for 30 minutes irrespective of the power or system type (clause 5.3.2); the cabling is likewise E30. Even where system autonomy is three hours (and can be eight hours in Austria and Germany), the fire-resistant enclosure is still E30 because functional integrity is required for 30 minutes in a fire. A longer period is not necessary because the luminaires themselves are not fire-resistant and E30 cables run to the first luminaire or to a fire-rated junction box in the fire compartment. The maximum building fire resistance is REI 120; after two hours the building's integrity may be seriously compromised and the risk of collapse high.
Q: How many luminaires may be connected to one CBS circuit?
A: Up to 20 luminaires per circuit (HRN HD 60364-5-56, clause 560.9.3).
Q: What is a mixed circuit in a CBS?
A: A mixed emergency lighting circuit combines maintained and non-maintained operation: some luminaires operate continuously while others switch on only when the power supply fails.
Q: How frequently must emergency lighting be checked or maintained?
A: HRN EN 62034, Chapter 5, and HRN EN 50172, Chapter 7, require tests, maintenance and servicing. The owner or user must appoint a responsible person to ensure regular servicing and allow all necessary work to keep the system in proper operating condition.
Q: Why use E30 junction boxes for emergency lighting cabling?
A: To reduce cabling requirements (fire-resistant and installation cables) and the number of circuits.
FAQ 66
FREQUENTLY ASKED QUESTIONS (FAQ) — CONTINUED
Q: Can automotive rechargeable batteries be used in a CBS?
A: Emergency lighting in the European Union is subject to strict requirements, including EN 60598-2-22, which defines technical and safety requirements for emergency lighting equipment, and EN 50171, which governs central emergency lighting power systems and their batteries. Batteries used in emergency lighting must also comply with applicable European battery legislation covering environmental protection, safety, labelling and disposal. They may also fall under the Restriction of Hazardous Substances (RoHS) requirements limiting hazardous substances in electronic products.
Q: When must emergency lighting switch on?
A: Emergency lighting must activate automatically when mains power fails or another emergency causes normal lighting to fail. Backup supplies such as batteries or generators are designed to start automatically in such circumstances.
Q: Must the signal cable from the main/sub-distribution board (GRO/RO) or fire alarm control panel (VDC) be fire-resistant?
A: No. A fire-resistant cable is not required for such a signal because the signal has no adverse effect on the operation of the central unit (DIN VDE 0100-560, clause 560.8.2).
Q: How is a direct-current circuit protected?
A: For safety, it must be equipped with two-pole circuit protection (DIN VDE 0100-560, clause 560.8.4).
Q: Why and where should supercapacitor luminaires be used instead of battery-powered luminaires?
A: Supercapacitor luminaires are used because of their long service life, fast charging and resistance to a wide temperature range. They are suitable for installations with frequent charging cycles and extreme conditions, for example garages.
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FREQUENTLY ASKED QUESTIONS (FAQ) — CONTINUED
Q: From how many emergency luminaires does a CBS become cost-effective?
A: A CBS typically becomes economically attractive for installations with more than 50–100 luminaires, depending on the building size, system complexity and maintenance costs. With fewer luminaires, individual batteries may be more economical; for larger numbers, a CBS can reduce maintenance costs, increase reliability and simplify system monitoring.
Q: Is a fire-resistant supply cable required between the CBS central unit and its substation?
A: Yes. A fire-resistant power supply cable is required to maintain system functionality in a fire. Such cables allow the emergency lighting system to remain operational for the prescribed period, which is essential for safe evacuation. The source refers to EN 50200 and DIN VDE 0100-560.
FAQ 68
REFERENCES
[1] Croatian Building Act (Official Gazette NN 153/13, 20/17, 39/19, 125/19, 145/24).
[2] Croatian Occupational Safety Act (NN 71/14, 118/14, 154/14, 94/18, 96/18).
[3] Croatian Fire Protection Act (NN 92/10, 114/22).
[4] Ordinance on occupational safety at workplaces (NN 105/20).
[5] Ordinance on basic fire-protection requirements for electrical power facilities and equipment (NN 146/05).
[6] Ordinance on fire protection in hospitality establishments (NN 100/99).
[7] Ordinance on fire alarm systems (NN 56/99).
[8] Ordinance on safety signs (NN 91/15).
[9] Ordinance on technical standards for low-voltage electrical installations (NN 05/10).
[10] Ordinance on fire resistance and other requirements for buildings in case of fire (NN 29/13).
[11] HRN EN 1838:2025 — Lighting applications: Emergency lighting for buildings.
[12] HRN EN 50171:2022/Corr.1:2024 — Central safety power supply systems.
[13] HRN EN 50172:2024 — Emergency escape lighting systems.
[14] HRN EN IEC 62485-2:2018 — Safety requirements for secondary batteries and battery installations, Part 2: Stationary batteries.
[15] HRN EN 62034:2013 — Automatic test systems for battery-powered emergency escape lighting.
[16] HRN EN IEC 12665:2024 — Light and lighting: Basic terms and criteria for specifying lighting requirements.
[17] HRN EN IEC 60598-2-22:2022 — Luminaires: Particular requirements for luminaires for emergency lighting.
[18] HRN HD 60364-5-56:2019 — Low-voltage electrical installations, Part 5-56: Selection and erection of electrical equipment — Safety services.
[19] HRN ISO 3864-1:2014 — Graphical symbols, safety colours and safety signs, Part 1: Design principles for safety signs and safety markings.
[20] HRN ISO 3864-4:2015 — Graphical symbols, safety colours and safety signs, Part 4: Colorimetric and photometric properties of safety sign materials.
[21] HRN EN ISO 7010:2020/A7:2025 — Graphical symbols, safety colours and safety signs: Registered safety signs.
[22] OVE E 8101:2019-01-01 + OVE E 8101/AC1:2020-05-01.
[23] OVE Guideline R 12-2:2019-01-01 + OVE Guideline R 12-2/AC:2019-07-01.
[24] Model Wiring Systems Directive (MLAR; version 10 February 2015, amended 3 September 2020, AM 2021/3).