Reference table
AWG Wire Resistance Table for Fire Alarm Circuits
Lookup copper conductor resistance values for fire alarm NAC and SLC voltage drop calculations using common AWG sizes.
AWG wire resistance table6 rows2 linked calculators
Rows
6
Reference values
Columns
2
Lookup fields
Linked tools
2
Calculators using this data
Source governance
Record how this table is used before carrying a value into a calculator, worksheet, or authority workflow.
| Governance item | Record | Use boundary |
|---|---|---|
| Source class | Electrical property lookup | Use the table as a controlled reference input, not as an adoption or approval database. |
| Last review basis | Static registry review | Re-check adopted standards, manufacturer data, and project criteria before final use. |
| Known limit | Temperature, insulation, listing, and circuit conditions can change final conductor selection. | Escalate unresolved code, listing, or jurisdiction questions to the project record. |
| Downstream record | Fire Alarm NAC Voltage Drop Calculator, Fire Alarm Wire Resistance Calculator, Fire Alarm Battery and NAC Worksheet | Keep selected rows with the worksheet, calculation package, or authority record. |
Reference table use
Use the table as controlled input data: select the row, verify the condition, and carry the value to the related calculator.
Usage context
- 1Use this table when selecting awg wire resistance table for preliminary fire protection calculator setup.
- 2Treat the lookup value as an engineering input that must be traceable to project conditions, manufacturer data, or adopted standard criteria.
- 3Apply the selected value before using 2 linked calculator workflows that depend on this reference.
Selection rules
- 1Match the row against the actual project condition before selecting a Wire Size / Ohms per 1000 ft value.
- 2Do not interpolate, round, or substitute a value unless the project calculation basis explicitly allows it.
- 3When multiple rows appear plausible, choose the conservative value and document the reason for the selection.
Review checks
- 1Selected row matches drawings, device listings, field readings, or occupancy assumptions.
- 2The selected value is carried into the downstream calculator with the correct units and label.
- 3The result is reviewed against 2 linked calculator uses before final design reliance.
| Reference field | How to use it | Related tools |
|---|---|---|
| Wire Size | Use this field to identify the matching project condition. | Fire Alarm NAC Voltage Drop Calculator, Fire Alarm Wire Resistance Calculator, Fire Alarm Battery and NAC Worksheet |
| Ohms per 1000 ft | Carry this value into the downstream calculator with the displayed units and label. | Fire Alarm NAC Voltage Drop Calculator, Fire Alarm Wire Resistance Calculator, Fire Alarm Battery and NAC Worksheet |
Copper Wire Resistance
| Wire Size | Ohms per 1000 ft |
|---|---|
| 12 AWG | 1.588 |
| 14 AWG | 2.525 |
| 16 AWG | 4.016 |
| 18 AWG | 6.385 |
| 20 AWG | 10.15 |
| 22 AWG | 16.14 |
Engineering disclaimer
NFPA in USA provides engineering workpapers, calculation checks, and reference tables for project screening and coordination. Final design decisions, code interpretations, submittals, and acceptance records must be completed by qualified professionals and verified against the adopted code, project criteria, listings, and Authority Having Jurisdiction requirements. This site does not issue signed or sealed engineering documents.Tools and workflows that use this table
FAQ
How should this wire resistance table be used?+
Use it as an engineering reference source for selecting values, checking assumptions, and documenting the basis carried into a calculator or worksheet.
Can this table replace the sealed project record?+
No. Values still need to be checked against the adopted standard, manufacturer data, project specifications, and Authority Having Jurisdiction requirements before they are used in final documents.