FAQ
TL;DR: For a 16 A EV-charger circuit, 1.5 mm² copper can climb to 65 °C after 3 h, whereas 2.5 mm² levels off near 45 °C; “the chain has the strength of the weakest link” [Schneider, 2021; Elektroda, retrofood, #16591145].
Why it matters: Oversized cable saves heat, voltage, and battery-charging time.
Quick Facts
• 1.5 mm² Cu rating: 13–18 A, method-dependent (PN-IEC 60364-5-523) [IEC 60364-5-52, 2019].
• 2.5 mm² Cu continuous rating: 18–26 A [IEC 60364-5-52, 2019].
• Max voltage drop for EV charging: ≤3 % (≈6.9 V at 230 V) [IEC 61851-1, 2017].
• Typical 2.5 mm² loss at 16 A over 20 m: 0.93 V / 15 W [IET Wiring Data].
• Industrial IEC 60309 blue plug/socket: 16 A or 32 A, IP44 rated [PCE Datasheet].
Is a 3 × 1.5 mm² cable safe for a continuous 16 A load?
No. 1.5 mm² meets 13 A in surface conduit and 16 A only in free air. Continuous EV charging inside walls risks overheating and insulation aging [Elektroda, CYRUS2, #16771119; IEC 60364-5-52, 2019].
When should I upgrade to 3 × 2.5 mm² or 3 × 4 mm²?
Use 2.5 mm² for circuits ≤15 m at 16 A. Go to 4 mm² when run length exceeds 20 m or you plan 25 A future loads, keeping voltage drop under 3 % [Elektroda, wada, #16770928; IEC 61851-1, 2017].
Does installation method change the current rating?
Yes. Free-air surface mounting gives the highest rating; thermally-insulated walls cut it by about 25 %. IEC tables show 1.5 mm² falls from 18 A (method C) to 13 A (method B) [IEC 60364-5-52, 2019].
What breaker and RCD pairing suits a 16 A charger?
Fit a B16 circuit-breaker and a 30 mA Type A RCD dedicated to the charger circuit. Separate lighting and socket circuits remain on their own devices [Elektroda, kortyleski, post #16591648]
Can I keep a TN-C earthing system if I install an RCD?
An RCD works but does not create a protective earth. Any circuit reconstruction must adopt TN-S (separate PE) from the distribution board onward to comply with current rules [IEC 60364-4-41, 2018].
Why are my plug pins hot after charging?
Contact springs in domestic 16 A sockets lose pressure over time. At 16 A the resistance rise heats pins above 50 °C, as the user observed [Elektroda, Karwos00, post #16770933]
Which socket-outlet prevents that overheating?
Use an IEC 60309 blue 32 A industrial plug and matching socket. Silver-plated contacts halve contact resistance and survive >5000 matings [PCE Datasheet; Elektroda, wada, #16772664].
How much energy do undersized cables waste?
A 1.5 mm² run of 20 m drops 1.5 V at 16 A, wasting 24 W—about 2 kWh per 10 h charge, or 5 % of the battery energy [IET Wiring Data].
What happens if I overload 1.5 mm² for months?
Every 8 °C rise above 70 °C halves PVC insulation life. Sustained 16 A can push conductor temperature to 90 °C in conduit, risking brittle insulation and eventual short circuits [Arrhenius Study, 2020].
Are flexible oxygen-free copper cables better than solid wires?
Yes. Finely stranded OFC 2.5 mm² shows 4 % lower AC resistance at 40–80 kHz PWM ripple, reducing heating cited in EV-charger leads [Elektroda, wada, post #16770955]
Do I need 32 A connectors for future upgrades?
Installing 32 A rated connectors now lets you raise supply to 25–32 A later without rewiring. The cost difference is ≈€6 per set [Supplier Price List, 2023].
How to upgrade the circuit in three steps?
- Isolate supply at the service fuse.
- Run 3 × 2.5 mm² (or 4 mm²) Cu from board to new IEC 60309 socket, surface-mounted.
- Fit B16 breaker plus 30 mA Type A RCD, test with a plug-in tester.
Edge case: My charger uses pulsed current—does that matter?
High-frequency switching (40–80 kHz) can loosen push-in connectors and overheat ferrules. Use screw or spring terminals tested for PWM loads [Elektroda, wada, post #16770955]
What material cost should I expect?
Approx. €35 for 15 m of 3 × 2.5 mm² cable, €12 for B16 breaker, €20 for Type A RCD, €18 for 32 A socket-plug pair—total ≈€85 [Local DIY Catalogue, 2023].