Understanding RCD Types

What an RCD Does

A Residual Current Device (RCD) protects you from electric shock and fire by cutting power if it detects a fault (current leaking to earth). In a van or off-grid setup, it’s fitted on the AC output side of your inverter to protect all sockets and appliances.

RCD Types Explained (for Van Life Systems)

Type AC – Standard Alternating Current
Detects pure AC residual currents only. Suitable for simple resistive loads. Not suitable for inverter or electronic systems. Examples: Old fan heaters, incandescent lights.

Type A – Pulsating DC Sensitive
Detects AC and pulsating DC residual currents. Best all-round choice for most van setups. Compatible with inverters, chargers and appliances with rectifiers. Examples: Pure sine inverters, chargers, laptops, LED drivers.

Type F – High-Frequency Sensitive
Detects AC + pulsating DC up to 1 kHz. Designed for variable-speed drives or inverter motors. Examples: Heat pumps, AC units, modern washing machines.

Type B – Smooth DC Sensitive
Detects AC, pulsating DC and smooth DC. Required where DC leakage is possible. Examples: EV chargers, solar inverters, large inverter-chargers.

Type B+ – Enhanced Protection
Like Type B but sensitive up to 20 kHz for specialist installations. Examples: Industrial/medical or advanced EV systems.

Quick Comparison Table

Type	Detects AC	Pulsating DC	Smooth DC	Frequency Range	Van-Life Suitability
AC	Yes	No	No	50/60 Hz	Outdated
A	Yes	Yes	No	50/60 Hz	Best for most vans
F	Yes	Yes	No	≤ 1 kHz	Specialist (inverter motors)
B	Yes	Yes	Yes	≤ 1 kHz	For inverter/EV charging
B+	Yes	Yes	Yes	≤ 20 kHz	Industrial/medical

Best Choice for Van Life

For most self‑built campervans using a pure sine‑wave inverter, a Type A RCD gives the right balance of safety and compatibility. If your system includes large inverter‑chargers, EV chargers, or solar inverters, upgrade to Type B.

Typical Van Electrical Layout

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