What is CCA Ampacity Quick Reference: Wire?

Stop guessing CCA wire sizes. This practical guide provides ready-to-use conversion tables, explains when CCA can directly replace copper (>1 MHz), and reveals the 5 most common sizing mistakes.

CCA Ampacity Quick Reference: Wire Sizing, Conversion Tables &…

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"We currently use 10mm² pure copper for our busbars. Our client suggested switching to CCA for cost savings, but we have no idea what wire gauge to specify. Do we just use the same cross-section? Or do we need to go bigger? How much bigger?"

— Senior Electrical Engineer, European EV Charger Manufacturer, Q1 2026

📌 30-Second Answer

✅ CCA cannot be same-size replacement: Due to ~62-68% IACS conductivity, CCA needs a 1.2–1.3× larger cross-section for the same ampacity.
📐 Quick formula: d_CCA ≈ d_Cu × 1.25 for diameter; or A_CCA ≈ A_Cu × 1.5 for cross-sectional area.
💡 Exception — high frequency (>1 MHz): Due to skin effect, CCA can directly replace copper at the same gauge for RF/coaxial applications.
📊 Below is a ready-to-use lookup table — skip the math and find your answer in 30 seconds.

✅ CCA 62-68% IACS CCA 1.2-1.3
📐 d_CCA ≈ d_Cu × 1.25 A_CCA ≈ A_Cu × 1.5
💡 >1 MHz CCA /
📊 30

1. The Physics: Why CCA Needs a Larger Cross-Section CCA

1.1 Conductivity Difference at a Glance1.1

Copper-clad aluminum (CCA) consists of an aluminum core bonded with a copper outer layer. The electrical conductivity depends on the copper volume ratio. For standard CCA-15% (15% copper by volume, the most common commercial grade):

**Table 1** Conductivity by CCA Grade vs. Pure Copper
Grade	Copper Volume %	IACS ConductivityIACS	Resistivity (μΩ cm)	vs. Pure Cu Ratio
CCA-10%	10%	55-60% IACS	2.87-3.13	1.67-1.82×
CCA-15%	15%	62-68% IACS	2.53-2.78	1.47-1.61×
CCA-20%	20%	68-72% IACS	2.39-2.53	1.39-1.47×
CCA-25%	25%	72-78% IACS	2.21-2.39	1.28-1.39×
Pure Copper	100%	100% IACS	1.72	1.00×

Figure 1 Cross-section of CCA-15% vs. pure copper conductor. The aluminum core (density 2.70 g/cm³) occupies ~85% of the volume, while the copper cladding (density 8.96 g/cm³) occupies ~15%. Current flows primarily through the copper outer layer at low frequencies; at high frequencies, skin effect concentrates current in the outer copper layer, making CCA performance approach that of solid copper.CCA-15% 2.70 g/cm³ 85% 8.96 g/cm³ 15% CCA

1.2 The Core Formula1.2

📐 CCA Wire Size Conversion FormulaCCA

For equal ampacity (same current-carrying capacity) at DC/low frequency:

A_CCA = A_Cu × (100 / σ_CCA)A_CCA = A_Cu × (100 / σ_CCA)

Where A = cross-sectional area (mm²), σ_CCA = CCA conductivity in % IACS

A = mm² σ_CCA = CCA % IACS

d_CCA = d_Cu × √(100 / σ_CCA)d_CCA = d_Cu × √(100 / σ_CCA)

Where d = conductor diameter (mm)

d = mm

⚡ Quick Estimate (CCA-15%):
d_CCA ≈ d_Cu × 1.25 | A_CCA ≈ A_Cu × 1.50
This gives a ~5% safety margin over the theoretical minimum.

⚡ CCA-15%
d_CCA ≈ × 1.25 | A_CCA ≈ × 1.50
5%

2. Ready-to-Use Lookup Tables

2.1 Metric Wire Gauge Conversion (CCA-15%)2.1 CCA-15%

Find your current copper wire size in the left column → the right column tells you what CCA size to use.

**Table 2** CCA-15% Wire Size Conversion — Metric (mm²)CCA-15% mm²
Cu Cross-Section (mm²)	Cu Diameter (mm)	Typical Ampacity* (A)*	CCA Cross-Section (mm²)CCA	CCA Diameter (mm)CCA	Nearest Standard CCACCA
0.5	0.80	6 A	0.75	0.98	0.75 mm² ✓
0.75	0.98	9 A	1.13	1.20	1.0 mm² ✓
1.0	1.13	12 A	1.50	1.38	1.5 mm² ✓
1.5	1.38	16 A	2.25	1.69	2.5 mm² ✓
2.5	1.78	22 A	3.75	2.19	4 mm² ✓
4	2.26	30 A	6.0	2.76	6 mm² ✓
6	2.76	38 A	9.0	3.39	10 mm² ✓
10	3.57	52 A	15.0	4.37	16 mm² ✓
16	4.51	70 A	24.0	5.53	25 mm² ✓
25	5.64	90 A	37.5	6.91	35 mm² ✓
35	6.68	115 A	52.5	8.18	50 mm² ✓
50	7.98	145 A	75.0	9.77	70 mm² ✓
70	9.44	180 A	105	11.57	95 mm² ✓
95	11.00	220 A	142.5	13.47	120 mm² ✓
120	12.36	260 A	180	15.14	150 mm² ✓

*Typical ampacity for single conductor in free air at 30°C ambient, 70°C max operating temperature. For bundled or enclosed installations, apply derating per IEC 60364-5-52. * 30°C 70°C IEC 60364-5-52

2.2 AWG Conversion (CCA-15%)2.2 AWG CCA-15%

**Table 3** CCA-15% AWG ConversionCCA-15% AWG
Copper AWGAWG	Cu Diameter (mm)	Cu Ampacity* (A)*	→ Use CCA AWG→ CCAAWG	CCA Diameter (mm)CCA	Notes
20 AWG	0.81	6 A	18 AWG ✓	1.02	+2 AWG (2 sizes up)2
18 AWG	1.02	10 A	16 AWG ✓	1.29
16 AWG	1.29	15 A	14 AWG ✓	1.63
14 AWG	1.63	20 A	12 AWG ✓	2.05
12 AWG	2.05	25 A	10 AWG ✓	2.59
10 AWG	2.59	35 A	8 AWG ✓	3.26
8 AWG	3.26	50 A	6 AWG ✓	4.11
6 AWG	4.11	65 A	4 AWG ✓	5.19
4 AWG	5.19	85 A	2 AWG ✓	6.54
2 AWG	6.54	115 A	1/0 AWG ✓	8.25
1/0 AWG	8.25	150 A	2/0 AWG ✓	9.27
2/0 AWG	9.27	175 A	3/0 AWG ✓	10.40
3/0 AWG	10.40	200 A	4/0 AWG ✓	11.68
4/0 AWG	11.68	230 A	250 kcmil ✓	—	Switch to kcmil sizingkcmil

⚠️ Rule of Thumb for AWG: Go up 2 AWG sizes for CCA-15% replacement. Example: 14 AWG Cu → 12 AWG CCA. This gives a ~5% safety margin in most cases.

⚠️ AWG CCA-15% 2AWG 14 AWG → 12 AWG CCA 5%

Figure 2 Required conductor cross-sectional area vs. target ampacity for CCA-15% and pure copper. The ratio A_CCA/A_Cu ≈ 1.50 remains approximately constant across the full current range for DC and low-frequency applications (≤400 Hz).CCA-15% ≤400 Hz A_CCA/A_Cu ≈ 1.50

3. The High-Frequency Exception: When CCA = Copper CCA =

There is one scenario where you can use the exact same gauge CCA as your copper wire: high-frequency applications above ~1 MHz. This is due to the skin effect — at high frequencies, current flows only on the conductor surface. Since CCA has a copper outer layer, the effective conducting cross-section is practically identical to solid copper.

>1 MHz CCA

**Table 4** Direct Replacement vs. Upsizing by Frequency
Frequency Range	Skin Depth in Cu (mm)	CCA vs CuCCA vs	Action
DC – 400 Hz	>10 mm	CCA needs 1.5× areaCCA1.5	Upsize per Table 22
400 Hz – 10 kHz	2.1 – 10 mm	Partial skin benefit	Upsize 1 AWG only1AWG
10 kHz – 1 MHz	0.066 – 2.1 mm	Significant skin benefit	Same gauge may work
>1 MHz	<0.066 mm	Near-identical performance	✅ Direct replacement

📐 Skin Depth Quick Check

δ = 66 / √f (mm, for copper at 20°C)mm 20°C

where f is frequency in Hz. If δ < wire radius → skin effect matters.

f Hz δ < →

Figure 3 Effective conductivity ratio (CCA/Cu) vs. frequency for a 2.5mm² conductor. Below 10 kHz, CCA delivers ~65% of copper's effective conductivity. Above 1 MHz, the ratio approaches 100% as skin depth becomes smaller than the copper cladding thickness.2.5mm² CCA/Cu 10 kHzCCA65% 1 MHz 100%

4. Real-World Calculation Examples

Example 1: Building Wiring (DC/50Hz)1 /50Hz

Scenario: You currently use 2.5mm² copper wire for a 16A lighting circuit. Want to switch to CCA-15%.

2.5mm²16A CCA-15%

Step 1: A_Cu = 2.5 mm², σ_CCA = 65% IACS (conservative)

1 A = 2.5 mm² σ_CCA = 65% IACS

Step 2: A_CCA = 2.5 × (100/65) = 2.5 × 1.538 = 3.85 mm²

2 A_CCA = 2.5 × (100/65) = 2.5 × 1.538 = 3.85 mm²

Step 3: Nearest standard size → 4.0 mm² CCA ✓

3 → 4.0 mm² CCA ✓

✓ Answer: Use 4mm² CCA to safely replace 2.5mm² copper for 16A circuits.

✓ 4mm² CCA2.5mm² 16A

Example 2: EV Charging Cable (DC, High Current)2

Scenario: 11kW EV charger uses 6mm² copper for each phase conductor (3-phase, 16A per phase).

11kW6mm² 16A

Step 1: A_Cu = 6 mm², target 16A per phase

1 A = 6 mm² 16A

Step 2: A_CCA = 6 × 1.538 = 9.23 mm²

2 A_CCA = 6 × 1.538 = 9.23 mm²

Step 3: Nearest standard → 10 mm² CCA ✓

3 → 10 mm² CCA ✓

✓ Answer: 10mm² CCA replaces 6mm² copper. Weight: 36.4 g/m vs 53.8 g/m ≈ 32% lighter.

✓ 10mm² CCA6mm² 36.4 g/m vs 53.8 g/m ≈ 32%

Example 3: Coaxial Cable (RF, High Frequency)3

Scenario: RG-6 coaxial cable carrying 2.4 GHz WiFi signal. Current center conductor: 18 AWG (1.02mm) solid copper.

RG-62.4 GHz WiFi 18 AWG 1.02mm

Step 1: f = 2.4 GHz → skin depth δ = 66/√(2.4×10⁹) = 0.0013 mm

1 f = 2.4 GHz → δ = 0.0013 mm

Step 2: CCA copper cladding thickness ≈ 0.05 mm >> 0.0013 mm skin depth

2 CCA ≈ 0.05 mm >> 0.0013 mm

Step 3: Current flows entirely within the copper cladding → CCA ≈ solid copper

3 → CCA ≈

✓ Answer: Direct replacement — 18 AWG CCA works identically to 18 AWG copper at 2.4 GHz.

✓ 18 AWG CCA2.4 GHz18 AWG

Figure 4 CCA wire sizing decision flow: (1) Identify your application frequency & current; (2) If DC/low-frequency → use the conversion table (Table 2/3); (3) If high-frequency (>1 MHz) or RF → direct same-gauge replacement is valid. Always verify with a thermal test before production.CCA (1) (2) / → 2/3 (3) >1 MHz →

🔑 Key Takeaways

1.25× Diameter Multiplier CCA-15% diameter vs Cu for equal ampacityCCA-15% vs

1.50× Area Multiplier Required CCA cross-section vs CuCCA vs

+2 AWG AWG Rule of ThumbAWG Go up 2 AWG sizes for CCA-15%CCA-15%2AWG

>1 MHz Direct Replacement Zone CCA = Copper due to skin effectCCA=

5. Common Mistakes 5

🚫 Mistake 1: Same-size replacement for DC applications1

One manufacturer replaced 4mm² copper with 4mm² CCA in a 30A DC busbar. Result: conductor overheated to 105°C (design limit: 70°C). Root cause: CCA at same cross-section carries only ~65% of copper's current.
✅ Fix: Always upsize by 1.5× cross-section area for DC/low-frequency. Use Table 2.

4mm² CCA4mm²30A 105°C 70°C CCA65%
✅ /1.5 2

🚫 Mistake 2: Ignoring termination temperature rise2

CCA conductors may have slightly higher contact resistance at terminals due to aluminum core creep. This can add 5-10°C at connection points.
✅ Fix: Use tin-plated copper terminals; apply controlled compression (15-20% compression ratio); measure temperature at terminals during validation, not just mid-span.

CCA 5-10°C
✅ 15-20%

🚫 Mistake 3: Using copper ampacity tables for CCA without conversion3 CCA

Engineers often look up "what current can 6mm² carry?" from standard copper tables and apply to CCA. This overestimates CCA ampacity by ~50%.
✅ Fix: Always convert: find copper ampacity → multiply wire area by 1.5 → look up the new size in a copper table (the ampacity value is valid for CCA at the larger size).

"6mm²" CCA CCA50%
✅ → ×1.5 → CCA

🚫 Mistake 4: Neglecting bundling derating4

CCA, like copper, requires derating when multiple conductors are bundled. But because CCA runs at slightly higher current density for the same size, thermal accumulation in bundles is more pronounced.
✅ Fix: Apply the same bundling derating factors from IEC 60364-5-52, but add an extra 5% margin for CCA bundles with >5 conductors.

CCA CCA
✅ IEC 60364-5-52 5CCA5%

🚫 Mistake 5: Not verifying CCA copper ratio from supplier5

Some low-cost CCA products claim "CCA-15%" but actually have only 8-10% copper by volume. This means 55-60% IACS instead of 65%, requiring even larger upsizing.
✅ Fix: Always request a certified test report with eddy current measurement or metallographic cross-section analysis. Calculate your upsizing based on the measured conductivity, not the nominal grade.

CCA"CCA-15%"8-10% 55-60% IACS65%
✅

6. FAQ

Q: Can I use the same terminal blocks and connectors with CCA?Q: CCA

A: Yes, but with caveats. Since CCA conductors are 1.25× larger diameter, ensure your terminals are rated for the larger wire gauge. Use tin-plated copper terminals (not bare brass) to minimize galvanic corrosion. Compression-type terminals are preferred over screw-type for CCA. See whitepaper: Termination Techniques for CCA A: CCA1.25 CCA

Q: What about voltage drop over long distances?Q:

A: Voltage drop is proportional to resistance. With CCA properly upsized (1.5× area), the resistance equals that of the original copper so voltage drop is identical. The key is: do the upsize correctly. If you skip the upsizing, voltage drop will be ~60% higher than with copper. Always calculate voltage drop with the actual CCA resistivity (2.5-2.8 μΩ cm), not copper values. See whitepaper: CCA vs Copper Cost-Effectiveness Analysis A: 1.5 CCA → 60% CCA 2.5-2.8 μΩ cm CCA vs

Q: Does temperature affect the conversion ratio?Q:

A: Slightly, but not enough to change your wire selection. CCA has a temperature coefficient of resistance (TCR) of ~0.0040/°C vs. copper's 0.00393/°C very close. At elevated temperatures (e.g., 90°C vs 20°C), the CCA/Cu resistance ratio changes by less than 2%. The 1.5× area rule remains valid across the full operating temperature range (-40°C to +150°C). See whitepaper: CCA Thermal Cycling Performance A: CCA0.0040/°C 0.00393/°C 90°C vs 20°C CCA/2% 1.5 -40°C+150°C CCA

Q: Is there an online calculator or app for this?Q: App

A: Raytron offers a free CCA Savings Calculator that includes wire size conversion. Input your current copper specification, and it calculates the equivalent CCA gauge, weight savings, and cost reduction. Bookmark it for your next design review. A: RaytronCCA CCA

7. Next Steps

🚀 3 Steps to Size Your CCA CorrectlyCCA

Use the lookup table Find your copper spec in Table 2 or 3 above, and the corresponding CCA size is right there. 23 CCA
Request free samples We'll send CCA wire samples in your target gauge for validation. Test them in your actual application. CCA
Get engineering support Our application engineers review your specific use case and confirm the optimal gauge selection at no cost.

📩 Request Free Technical Consultation & Samples

CCA Ampacity Quick Reference: Wire Sizing, Conversion Tables & Common Mistakes