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Which intrinsic safety barrier can I use with the SOC-E-IS and YBN-R/4IS?

Use either a certified shunt Zener barrier rated 30 V, 200 mA and 1 W or less, or one channel of a Pepperl+Fuchs KFD0-CS-Ex1.51P or KFD0-CS-Ex2.51P galvanic isolator, as shown in the SOC-E-IS system drawing.

Direct answer

The SOC-E-IS is not SIL2 certified (per datasheet ISS6, September 2025); if you need SIL2, ask Hochiki Europe Technical Support which intrinsically safe option is current. Its circuit must be fed through a Zener diode barrier or a galvanic isolator selected from the SOC-E-IS installation instructions system drawing — Pepperl+Fuchs KFD0-CS-Ex1.51P or KFD0-CS-Ex2.51P, or a compliant Zener barrier — subject to the circuit’s detector-count, cable and earthing limits. It holds LPCB approval to BS EN 54-7, ATEX certificate BASEEFA19ATEX0143X and IECEx BAS 19.0122X. Confirm current certification and availability with Hochiki Europe Technical Support before specifying.

Applies to

  • Products / Models: SOC-E-IS, SOC-E-IS(WHT); YBN-R/4IS base (also written YBN-R/4(IS)), YBN-R/4IS(WHT); KFD0-CS-Ex2.51P and KFD0-CS-Ex1.51P isolated barriers (Hochiki datasheets write these as KFD0-CS-EX2.51P and KFD0-CS-EX1.51P)
  • Firmware / Version: Not applicable
  • Region: UK / Europe
  • Standards: BS EN 54-7 (point smoke detectors; DoP 2831-CPR-F4344, LPCB certified). Explosive atmospheres: BS EN 60079-11:2012, ATEX certificate BASEEFA19ATEX0143X and IECEx BAS 19.0122X, marking II 1 G Ex ia IIC T5 Ga (-20°C ≤ Ta ≤ +55°C), suitable for Category 1, 2 or 3 areas up to 55°C ambient. Installation to BS EN 60079-14.

Product compatibility and certification — key points

Intrinsic safety conditions that must be met

  • Every SOC-E-IS circuit must be fed through a Zener diode barrier or a galvanic isolator selected from the system drawing in the SOC-E-IS installation instructions (2-3-0-2853) — see "Intrinsically safe interface" below for the approved devices.
  • A maximum of 20 SOC-E-IS detectors with YBN-R/4IS bases may be connected to one certified circuit.
  • Up to 20 additional simple-apparatus devices (for example CCP-E-IS manual call points, or other switches certified or classified as simple apparatus to BS EN 60079-11:2012) may share the same certified circuit. Any resistor fitted in series with such a switch must also have a body surface area of 230mm2 or more (typically 470 to 680 ohm).
  • The interconnecting cable must not exceed the capacitance, inductance and L/R limits for the gas group — for IIC, 0.07 µF, 0.62 mH and 36 µH/ohm.
  • The end-of-line resistor, and any resistor fitted in series with a switch, must have a body surface area of 230mm2 or more.
  • The hazardous-area circuit must withstand a 500 V a.c. test to earth for one minute. If a cable screen is used, it must be earthed only in the safe area.
  • The system must carry a durable label identifying it as a certified system (for example "System No. BAS Ex 98D2264").
  • The YBN-R/4IS base may only be fitted with Hochiki intrinsically safe detector heads. Fitting any other head is forbidden and may cause fire or explosion.
  • The installation must also comply with national requirements.

SOC-E-IS detector

  • SIL2: The current SOC-E-IS datasheet (ISS6, September 2025) does not list SIL certification; its approvals are LPCB, VdS, DNV, ATEX BASEEFA19ATEX0143X and IECEx BAS 19.0122X. Hochiki has offered SIL2-approved intrinsically safe detection products separately from the SOC-E-IS range. If your project requires a SIL2-rated intrinsically safe detection loop, contact Hochiki Europe Technical Support for the current option before specifying.
  • Datasheet: The latest SOC-E-IS datasheet is available from Hochiki (link provided by Hochiki technical support).
  • Certification: The SOC-E-IS datasheet issue 6 (September 2025) lists LPCB approval to BS EN 54-7 (DoP 2831-CPR-F4344), ATEX certificate BASEEFA19ATEX0143X and IECEx certificate BAS 19.0122X, with marking Ex ia IIC T5 Ga (-20°C ≤ Ta ≤ +55°C) for Category 1, 2 or 3 hazardous areas up to 55°C ambient. Certificate status can change; check the current certificate on the IECEx online certificate system before relying on it for a specification.
  • Intrinsically safe interface: The SOC-E-IS and its YBN-R/4IS base must be supplied through either a Zener diode barrier or a galvanic isolator, selected in accordance with the system drawing in the SOC-E-IS installation instructions (2-3-0-2853). The system drawing permits either (a) any BASEEFA-certified shunt safety Zener diode barrier rated 30 V or less, 200 mA or less and 1 W or less, whose barrier earth is connected through an insulated conductor equivalent to 4mm2 copper with an impedance to the main power system earth of less than 1 ohm, or (b) one channel of a BASEEFA-certified galvanic isolator listed in the drawing: Pepperl+Fuchs KFD0-CS-Ex1.51P or KFD0-CS-Ex2.51P. The system drawing records these against certificate number Ex96D2152; the isolator manufacturer's own certification has since been renumbered, so confirm the isolator's current ATEX and IECEx certificates with Pepperl+Fuchs before specifying. Galvanic isolators do not require the barrier earthing arrangement described for Zener barriers. See "Intrinsic safety conditions that must be met" above for the full circuit requirements. Always work from the current installation instructions for the exact model, not from this article.
  • Production status: The current SOC-E-IS datasheet is issue 6 (September 2025). Datasheets do not state production or availability status, so confirm current availability with Hochiki Europe before ordering.

Training and integrator qualification

  • Hochiki Europe training: Hochiki Europe runs product training for approved partners. Contact Hochiki Europe Technical Support for the current schedule and entry requirements.
  • Hazardous area competence: Work in hazardous areas additionally requires competence in explosive-atmosphere installation practice to BS EN 60079-14.

When to contact technical support

Contact Hochiki Europe Technical Support for confirmation of current certification, production status or approved intrinsic safety barriers before specifying this product for a hazardous area installation, or if you require guidance beyond the scope of this article.

Safety note

This article is general guidance for Hochiki Europe products. Design, installation, commissioning, maintenance and modification of fire detection and alarm systems should be carried out by, or under the responsibility of, a competent person in accordance with the applicable standards (for example BS 5839-1 in the UK). Statutory requirements imposed by the relevant enforcing authority also apply. Always refer to the current product manual and data sheet for the exact model before carrying out any work.

References

Last reviewed: 2026-10-21 — Reviewed by: Hochiki Europe Technical Support