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Courses/Cable Sizing & Installation/Mineral Insulated (MICC) Cable

lesson · 8min · Lesson 22 of 28

Fire performance cables: FP200, LSOH

Course syllabusCourse overview
01Current-Carrying Capacity
  1. ReadHow CCC tables work: Appendix 4
  2. ReadReference method A: enclosed in conduit
  3. ReadReference method B: clipped direct
  4. ReadReference methods C, E, F, G
  5. exerciseCCC selection problems
02Derating & Correction Factors
  1. ReadAmbient temperature correction (Ca)
  2. ReadGrouping correction factor (Cg)
  3. ReadThermal insulation factor (Ci)
  4. ReadDepth of burial correction (Cs)
  5. exerciseApplying multiple correction factors
03Voltage Drop Calculations
  1. ReadWhy voltage drop matters: Reg 525
  2. ReadmV/A/m tables and how to use them
  3. ReadCalculating voltage drop for single-phase
  4. ReadThree-phase voltage drop
  5. exerciseVoltage drop problems set
04Armoured Cables
  1. ReadSWA construction: layers and materials
  2. ReadUnderground cable installation methods
  3. ReadSWA as protective conductor?
  4. ReadXLPE vs PVC insulation
  5. exerciseSWA sizing exercise
05Mineral Insulated (MICC) Cable
  1. ReadMICC construction and applications
  2. ReadFire performance cables: FP200, LSOH
  3. ReadCable selection for life safety systems
  4. quizFire cable quiz
06Full Cable Sizing Design
  1. ReadEnd-to-end cable sizing: worked design
  2. ReadDocumenting the cable schedule
  3. ReadCommon errors and how to avoid them
  4. quizFinal assessment
Lesson · 8min
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In this lesson

PurposeCore theoryWorked exampleKnowledge checkSources

In this lesson

PurposeCore theoryWorked exampleKnowledge checkSources
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ElectraCore lesson handout

Fire performance cables: FP200, LSOH

Cable Sizing · Lesson 22 · Advanced

AdvancedReview: professional review pending

Purpose

Distinguish reaction-to-fire, smoke/acidity and circuit-integrity claims for named fire-performance cables.

Before you beginCable sizing workflow · Fire strategy and safety-service basics

Learning objectives

  • Identify the governing function
  • Select evidence on the correct basis
  • Coordinate the complete installed system
  • Record limitations

FP200 is a product-family name and LSOH describes limited smoke/halogen behavior; neither phrase alone declares the required duration, impact, water-spray or application compliance.

FIRE-SURVIVING CABLE SYSTEMFIRE-SURVIVING CABLE SYSTEMIbloadIndeviceIzIt × applicable factorsphysical method · exact table · declared conditions · all design gates

Core theory

Reaction to fire describes contribution to fire; resistance/circuit integrity describes continued function under a specified fire test. They are different classifications.

Select the current cable product standard and application category, including required survival time and test exposure. Verify certificate scope, conductor size, accessories and installation method.

Approved Document B editions and transition rules are jurisdiction/project-date specific. Application standards such as BS 5839-1:2025 can change independently of BS 7671.

Terms, symbols, and units
TermMeaningSymbolUnit
LSOHLow smoke, zero halogen product characteristic; verify exact declarationNot applicableNot applicable
Circuit integrityContinued electrical function under a defined testNot applicableNot applicable
Reaction to fireHow a product contributes to fire and smokeNot applicableNot applicable
Worked exampleA schedule says only 'red LSOH fire cable'.

Assumptions: Only the stated fictional project data apply.

  1. Reject shorthand: Colour and LSOH do not state survival category.
  2. Derive duty: Use fire strategy and current application standard.
  3. Specify: Record exact cable standard/category, tested accessories, route and supports.

The schedule is incomplete until the required function and certified installed system are specified.

Reasonableness check: The conclusion follows the declared function and evidence rather than a cable nickname.

Common mistakes
  • Selecting by trade name or sheath colour
  • Confusing low smoke with circuit integrity
  • Ignoring supports, joints, routes or terminations

Where this appears in practice

Competent designers coordinate electrical design with the building fire strategy, system standard, product certification and maintainable records.

SafetyFailure of a safety-service circuit during fire can endanger occupants and firefighters. Design, installation, inspection and testing require competent control.
Local code checkConfirm the building fire strategy, authority having jurisdiction, current BS 7671 and application standard (for example BS 5839, BS 5266 or BS 8519), exact tested cable/support/termination system, product certification, route, segregation, protection and documentation. Product names and LSOH labels never substitute for evidence. Isolate and prove dead before work.

Knowledge check

Does LSOH mean fire resistant?

No. Smoke/halogen behavior and circuit integrity are separate claims.

Answer: No. Smoke/halogen behavior and circuit integrity are separate claims.

Practical exercise

Audit four fictional datasheets and separate reaction-to-fire evidence from circuit-integrity evidence.

Summary

  • Function determines evidence
  • The tested installed system matters
  • Document every assumption

Sources and review

  • BS 5839-1:2025: Fire detection and fire alarm systems for non-domestic premises: BSI; 2025; United Kingdom
  • Approved Document B: Fire safety: UK Government; Current applicable edition and transition must be confirmed; England
  • Amendment 4:2026 impact on BS 7671: IET; 2026; United Kingdom

Editorial review date: 2026-08-22. Professional electrical review is pending.

Educational material for learning and preliminary checks. Verify current local requirements and exact equipment instructions. This lesson does not replace competent professional work.

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