Canada Voltage Drop Calculator
Voltage drop calculator for Canadian electrical installations using CEC standards. Enter voltage, current, wire distance, gauge, and phases to calculate voltage drop percentage and verify compliance with Canadian Electrical Code limits.
Regional Rule Context
Canada Rates and Rules
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Current draw of the load in amperes
Distance from panel to load (one way)
Result
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Canadian voltage drop calculator compliant with the Canadian Electrical Code (CEC). CEC Rule 8-102 recommends maximum 5% total voltage drop from service entrance to final outlet (3% for feeders, 2% for branch circuits). Calculates voltage drop for copper and aluminum conductors in AWG sizes 14 through 4/0. Supports 120V, 240V, 208V, and 347/600V circuits. Single-phase and three-phase calculations. Considers conductor temperature rating (60C, 75C, 90C) and conduit type. Wire resistance values per NEC/CEC tables.
Disclaimer: This calculator uses publicly available rules effective as of Jan 1, 2025 (version 1.0). Results are for informational purposes only. Always verify with official sources or a qualified professional. Last reviewed: Apr 1, 2026.
Formula
Calculates the voltage lost along a wire run based on wire resistance, current draw, and distance. The factor of 2 accounts for the supply and return conductors. For three-phase circuits, the factor changes to 1.732 (square root of 3). CEC Rule 8-102 limits voltage drop to 3% for branch circuits and 5% total for feeder plus branch.
Canada FAQs
What is the maximum voltage drop allowed by the CEC?
The Canadian Electrical Code (CEC) Rule 8-102 recommends a maximum total voltage drop of 5% from the service entrance to the final point of use. This is typically split as 3% maximum for feeders and 2% maximum for branch circuits. While this is technically a recommendation and not a mandatory rule, inspectors in most Canadian jurisdictions enforce it as a requirement.
How do I calculate voltage drop for a circuit?
Voltage drop equals 2 times the wire length times the current times the wire resistance per metre, divided by 1,000. For a 120V, 15A circuit with 14 AWG copper wire running 30 metres, the voltage drop is approximately 5.9V or 4.9%. If the drop exceeds 3% for a branch circuit, you need to upsize the wire to 12 AWG, which reduces the drop to approximately 3.7V or 3.1%.
When should I use aluminum vs copper wire in Canada?
Copper is standard for branch circuits (14 AWG to 10 AWG) in Canadian residential and commercial work. Aluminum is commonly used for larger feeder and service entrance cables (4 AWG and above) because it costs 40% to 60% less than copper. Aluminum has higher resistivity, so you need to upsize by approximately 2 AWG sizes compared to copper for the same voltage drop.
What wire size do I need for a 200-amp service in Canada?
A 200A residential service in Canada typically uses 3/0 AWG copper or 250 kcmil aluminum conductors. For service runs over 30 metres, you may need to upsize to 4/0 copper or 300 kcmil aluminum to keep voltage drop under 3%. The CEC requires the grounding electrode conductor to be at least 6 AWG copper for a 200A service.
Does wire temperature affect voltage drop?
Yes. Wire resistance increases with temperature. At 75C, copper wire has approximately 12% higher resistance than at 25C. For long runs in hot environments (attics, conduit exposed to sunlight), use the 75C or 90C resistance values for accurate voltage drop calculations. The CEC wire ampacity tables are based on 30C ambient temperature.
What voltage is standard for Canadian homes?
Canadian homes receive 240V split-phase power (two 120V legs). Most outlets and lighting circuits are 120V. Large appliances like dryers, ranges, and central AC use 240V. The nominal voltage is 120/240V, but actual voltage can range from 114V to 126V (120V plus or minus 5%). Commercial buildings commonly use 347/600V three-phase for lighting and HVAC.
How does the CEC differ from the NEC for voltage drop?
The Canadian Electrical Code and the US National Electrical Code have similar voltage drop recommendations (5% total, 3% feeder, 2% branch). However, the CEC uses metric wire sizes alongside AWG and has different ampacity tables for Canadian temperature ratings. The CEC also has specific rules for aluminum wiring connections that differ from US practice due to historical issues with aluminum branch circuit wiring in Canadian homes.
Do EV charger circuits need special voltage drop calculations?
Yes. A 48A Level 2 EV charger (60A circuit) drawing power over a long garage or driveway run is one of the most common residential voltage drop concerns. A 6 AWG copper wire at 25 metres has approximately 3.2% drop at 48A on a 240V circuit, which is acceptable. At 35 metres, the drop exceeds 4.5%, requiring an upsize to 4 AWG copper to stay within CEC limits.
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