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Cable Sizing result

Pass

Selected cable

6.0mm²

Tabulated capacity (Iz)
58.0 A
Required tabulated (It)
45.0 A
CurrentIb=45 A ≤ Iz=58 A
Volt drop2.3% (≤ 3%, lighting)

Calculation reference

BS 7671 Table 4E2A

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CIBSEBS 7671ASHRAEBS ENISO

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One workspace. Every MEP discipline.

Every calculation referenced to the engineering standard

AC & Refrigeration

  • Space Load CIBSE Guide A / ASHRAE Fundamentals
  • Solar Gain CIBSE Guide A
  • Refrigeration Loads IOR Cold Store CoP 2020 / ASHRAE
  • Refrigerant Pipe Sizing ASHRAE Refrigeration 2022 / Danfoss
  • Condensate Drain CIBSE Guide G / AD H / BS EN 12056-2
  • Machinery Room BS EN 378-3

Ventilation

  • Ventilation Design CIBSE Guide A / AD F / BB101 / HTM 03-01 / BS EN 16798-1
  • Whole Dwelling Approved Document F Vol 1 (2026)
  • Natural Ventilation BS EN 16798-7 / CIBSE Guide A / AD F
  • AHU Duty CIBSE Guide B3 / ASHRAE Fundamentals Ch.1 / AD L Vol 2
  • Standalone Fan Approved Document L Vol 2 / CIBSE Guide B4 / AMCA 208
  • Duct Sizing CIBSE Guide B2 / Guide C
  • Ductwork Pressure Loss CIBSE Guide C
  • Duct Insulation BS 5422:2023
  • Grille CIBSE Guide B2
  • Louvre CIBSE Guide C
  • Duct Noise CIBSE Guide B4

Plumbing & Heating

  • Heat Loss CIBSE Domestic Heating Design Guide 2026 / BS EN 12831-1:2017
  • Heat Source Sizing CIBSE Guide B1 / AM16 · CIBSE Domestic Heating Design Guide 2026 · MCS MIS 3005-D / MCS 031 a)
  • Heat Pump Noise MCS 020 a Issue 1.1)
  • Ground Loop Sizing MCS MIS 3005-D / MGD 007
  • Underfloor Heating BS EN 1264-2:2021 / CIBSE Domestic Heating Design Guide 2026 / MCS MGD 007
  • Expansion Vessel BS EN 12828 Annex D and UK National Annex / CIBSE Domestic Heating Design Guide 2026
  • Hydronic Pipe Sizing CIBSE Guide C / CIBSE Domestic Heating Design Guide 2026
  • Pipe Insulation BS 5422:2023 / CIBSE Domestic Heating Design Guide 2026
  • Cold Water Pipe Sizing CIBSE Guide C / Guide G / BS EN 806-3
  • Hot Water Storage CIBSE Guide G / CIBSE Domestic Heating Design Guide 2026 / MCS MIS 3005-D
  • Drainage BS EN 12056-2 and -3 / AD H

Electrical

  • Circuit Design BS 7671
  • Voltage Drop BS 7671 Appendix 4
  • Fault Level BS 7671 Appendix 14
  • Load Schedule IET On-Site Guide Table A2
  • DB Schedule BS 7671 Reg 536.4.202 / BS EN IEC 61439-1
  • Motor Starter BS EN IEC 60947-4-1:2019 / BS 7671
  • Power Factor Correction BS 7671 / CTG007
  • Generator ISO 8528-1 / -5
  • UPS IEC 62040-3:2021
  • Lighting Design BS EN 12464-1:2021
  • Emergency Lighting BS 5266-1:2025 / BS EN 1838:2024
  • EV Charging BS 7671 Section 722

Renewables

  • Solar Thermal MCS 024:2025 / SAP 10.3 Appendix H / MCS MIS 3001
  • PV Sizing MCS 032:2025 / SAP 10.3 Appendix M / MCS MIS 3002
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Electrical
HVAC
Plumbing
Refrigeration
Cable sizingBS 7671
Voltage dropBS 7671
Fault levelsBS 7671 App 14
1

Select

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Design Current (Ib)A
32.5
Installation MethodBS 7671 Table 4E2A
Method C
Lengthm
15
2

Enter

Every input field carries the source standard. Hover any field to see the table or clause it pulls from.

Cable Sizing ResultPASS
Size2.5mm²
Capacity (Iz)33.0 A
Volt drop4.03%
PDF report preview
3

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