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Navigating Energy Efficiency Testing for External Power Supplies: An In-Depth Look at CAN/CSA C383-13 (2018)
A comprehensive technical overview of Canada’s standard for determining the energy efficiency of external power supplies, covering scope, test methods, and compliance implications.
Introduction
External power supplies (EPS) are ubiquitous in modern electronics—from laptop chargers to set-top box adapters. In Canada, the energy performance of these devices is regulated under the Energy Efficiency Act, and the cornerstone test method for determining their efficiency is CAN/CSA C383-13 (2018). Officially titled “Test method for determining the energy efficiency of external power supplies,” this standard provides a repeatable, accurate procedure for measuring active-mode efficiency and no-load power consumption. Reaffirmed in 2018, it remains the current reference for manufacturers, testing laboratories, and regulatory bodies.
This article offers a technical walkthrough of the standard’s scope, core requirements, practical implementation considerations, and compliance pathways.
Scope and Applicability
CAN/CSA C383-13 (2018) applies to single‑voltage external AC‑DC or AC‑AC power supplies that are intended to be used with household, office, or commercial electronic equipment. The standard explicitly covers units with a nameplate output power of ≤ 250 W, which is the typical range for most consumer EPS products. It does not include DC‑DC converters, battery chargers paired with removable batteries, or industrial power supplies above 250 W.
The primary purpose of the standard is to define test conditions, instrumentation requirements, and calculation methods so that efficiency results are comparable across different laboratories and product types. While the standard itself does not set minimum efficiency levels, it is referenced by Canadian regulations (e.g., the Energy Efficiency Regulations) that do prescribe mandatory thresholds. As of 2024, any EPS sold in Canada must meet the efficiency levels established under those regulations, and CAN/CSA C383-13 is the prescribed test method.
Tip: Even if your target market is the United States, note that CAN/CSA C383‑13 is closely harmonized with the U.S. DOE test procedure (10 CFR Part 430, Appendix Z). Testing to this standard can often satisfy both Canadian and U.S. requirements with minimal adjustments.
Technical Requirements
Test Conditions
Accurate efficiency measurement requires strict control of ambient conditions and voltage/frequency inputs. The standard mandates:
- Ambient temperature: 23 °C ± 5 °C during the entire test sequence.
- Input voltage: 115 V ± 1 % at 60 Hz ± 1 % for the North American market; for units capable of universal input, testing may also be required at 230 V/50 Hz.
- Warm‑up period: The unit must be operated at rated load for at least 30 minutes before any readings are taken.
- Instruments: Power meters must have a resolution of at least 0.01 W and an accuracy of ± 0.5 % of reading in the frequency range of 50–60 Hz.
Measurement Points
Efficiency is determined by measuring the input power (Pin) and output power (Pout) at several load points. The required load levels as a percentage of the nameplate output current are shown in Table 1.
| Load Step | % of Nameplate Output Current | Measurement Duration | Notes |
|---|---|---|---|
| 1 | 100 % | ≥ 2 minutes | Peak load; record after stabilization |
| 2 | 75 % | ≥ 2 minutes | Intermediate load |
| 3 | 50 % | ≥ 2 minutes | Half load; typically the highest efficiency region |
| 4 | 25 % | ≥ 2 minutes | Low load; often used for efficiency class determination |
| 5 | 0 % (no‑load) | ≥ 5 minutes | No‑load input power; critical for standby power compliance |
Table 1: Required load points for efficiency measurement per CAN/CSA C383‑13 (§5.2).
Efficiency Calculation
The average active‑mode efficiency is the key metric. It is calculated as the arithmetic mean of the efficiencies at 25 %, 50 %, 75 %, and 100 % load:
ηavg = (η25% + η50% + η75% + η100%) / 4
Where ηXX% = Pout / Pin × 100 % at that load point. The no‑load power (Pno) is simply the measured input power with the output disconnected and must be reported separately, along with the average efficiency.
Important: All efficiency measurements must be performed using a resistive load unless the EPS is designed specifically for a non‑resistive output (e.g., for LED lighting). If the EPS includes a power factor correction (PFC) circuit, the input power must be measured using a true‑RMS power meter that correctly captures non‑sinusoidal waveforms.
Implementation Highlights
Successfully applying CAN/CSA C383‑13 in a test laboratory or production environment requires attention to several practical details:
Instrumentation Setup
- Current sensors: Use low‑burden shunts or Hall‑effect sensors that do not introduce significant voltage drop in the output circuit.
- Voltage measurement: The output voltage must be measured as close as possible to the output terminals of the EPS to avoid IR‑drop errors.
- Data acquisition: Readings should be taken after the load has been applied for at least two minutes, and the final value should be the average of at least three consecutive samples that vary by less than 1 %.
Load Selection
The load at each step must be adjusted to produce the exact percentage of the nameplate output current. If the EPS is rated in watts, the load resistance is calculated to draw the corresponding current at the nominal output voltage. Specially designed programmable DC loads are common, but the standard also permits fixed resistors for each load point—provided they are within ± 1 % of the target current.
No‑Load Measurement
No‑load power is measured with the output disconnected and the input voltage applied and stable for at least five minutes. This measurement is particularly sensitive to ambient temperature and input voltage harmonics; laboratories should ensure a clean sine wave supply (THD < 3 %) for reproducible results.
Harmonization note: CAN/CSA C383‑13 (2018) is largely consistent with IEC 62301 (Ed. 2.0, 2011) for no‑load power measurement and with the U.S. DOE test procedure for active mode. This alignment helps manufacturers that export to both Canada and the United States streamline their testing programs.
Compliance Notes
Compliance with CAN/CSA C383‑13 is typically a regulatory requirement rather than a voluntary step. In Canada, the Energy Efficiency Regulations mandate that all EPS products sold in the country meet minimum efficiency levels, which are verified using the test method in C383‑13. Key compliance aspects include:
- Verification by accredited labs: Test results must come from laboratories accredited to ISO/IEC 17025 for this specific standard.
- Reporting: Manufacturers must submit a compliance report including the measured average efficiency, no‑load power, and product identification information. The report must be retained for a specified period (typically 5 years) and provided to regulators upon request.
- Marking: Some products may be required to display an energy efficiency mark or include the efficiency data on the nameplate.
- Updates: Although the standard was reaffirmed in 2018, Canadian regulations have been updated to cover newer EPS types (e.g., multiple‑voltage outputs, USB‑PD capable units). Always check the latest version of the Energy Efficiency Regulations alongside the standard.
Warning: Testing a product with a 230 V rating using only the 115 V procedure can lead to non‑compliance if the unit later operates in Canada at the higher voltage (e.g., for dual‑voltage products). The standard requires testing at the voltage for which the EPS is intended; for universal input units, both 115 V and 230 V tests may be necessary.
Manufacturers are advised to maintain close communication with certified testing bodies and to review regulatory updates annually. While CAN/CSA C383‑13 provides a stable test method, the efficiency thresholds are periodically tightened to align with international best practices.
Frequently Asked Questions
Q: Is CAN/CSA C383‑13 mandatory for all external power supplies in Canada?
A: Yes, if the EPS is within the scope (single‑voltage, ≤ 250 W output) and sold into the Canadian market. The Energy Efficiency Regulations legally require compliance with the efficiency limits, and C383‑13 is the only approved test method for demonstrating conformance.
A: Yes, if the EPS is within the scope (single‑voltage, ≤ 250 W output) and sold into the Canadian market. The Energy Efficiency Regulations legally require compliance with the efficiency limits, and C383‑13 is the only approved test method for demonstrating conformance.
Q: Does the standard cover USB‑C Power Delivery (PD) chargers?
A: The 2018 version does not specifically address multi‑voltage outputs or adaptive voltage regimes. However, regulatory interpretations generally require that testing be performed at the highest intended output voltage and current that the EPS can sustain continuously. Future versions of the standard (or regulatory updates) are expected to include explicit provisions for PD and similar technologies.
A: The 2018 version does not specifically address multi‑voltage outputs or adaptive voltage regimes. However, regulatory interpretations generally require that testing be performed at the highest intended output voltage and current that the EPS can sustain continuously. Future versions of the standard (or regulatory updates) are expected to include explicit provisions for PD and similar technologies.
Q: What tolerances are allowed during load adjustment?
A: The current at each load step must be within ± 1 % of the target percentage of the nameplate output current. If the target is 50 % of 2 A, the test current must be 1.00 A ± 0.01 A.
A: The current at each load step must be within ± 1 % of the target percentage of the nameplate output current. If the target is 50 % of 2 A, the test current must be 1.00 A ± 0.01 A.
Q: How does this standard relate to IEC 62301?
A: For no‑load power, CAN/CSA C383‑13 is harmonized with IEC 62301 (Ed. 2.0). For active mode, the Canadian method has minor differences in stabilization times and load selection, but results are generally comparable. Some test reports use both standards to satisfy multiple markets.
A: For no‑load power, CAN/CSA C383‑13 is harmonized with IEC 62301 (Ed. 2.0). For active mode, the Canadian method has minor differences in stabilization times and load selection, but results are generally comparable. Some test reports use both standards to satisfy multiple markets.
© 2026 – Technical article prepared for informational purposes. Always refer to the latest official version of the standard for compliance.