Guides · TOSUNLUX
30 mA or 300 mA, type AC or type A: which RCCB to choose?
A residual current circuit breaker compares the current going out with the current coming back. If some is missing, part of it is leaking to earth, perhaps through a person: it trips. Two settings define it, its sensitivity and its class. TOSUNLUX (Tosun) TSL3-63 residual current circuit breakers come in 30 and 300 mA, classes AC and A.
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The short answer
- 30 mA: protection of people. This is the sensitivity for the circuits of a home.
- 300 mA: protection of installations against insulation faults and fire risk, not of people.
- Type AC: ordinary alternating currents (lighting, sockets, heating).
- Type A: in addition, leakage with a DC component produced by electronics (washing machine, cooktop, variable speed drives).
Sensitivity: 30 mA or 300 mA
The sensitivity IΔn is the leakage current above which the device trips. 30 mA is the threshold used to protect people against indirect contact: it is the one for the final circuits of a home, a shop or an office.
300 mA protects the installation: it detects an insulation fault before it heats up a cable or a piece of equipment. It does not protect a person. It is found at the head of an installation, on industrial circuits or for some equipment. Note: a standard 300 mA device at the head is not selective with 30 mA devices downstream; on a fault, it may trip before them. Have your electrician validate the layout.
The class: AC or A
Type AC detects sinusoidal alternating leakage currents. It suits lighting, sockets and conventional heating.
Type A also detects pulsating DC leakage currents, produced by electronic appliances: washing machines, cooktops, some drives and power supplies. Following NF C 15-100 practice, washing machine and cooktop circuits are placed behind a type A device.
TSL3-63 references
TSL3-63 devices comply with IEC/EN 61008-1, with a rated conditional short-circuit current of 6,000 A and the same DIN-rail mounting as the circuit breakers.
| Poles | Ratings | Sensitivities | Supply | Width |
|---|---|---|---|---|
| 2P (1P+N) | 25 · 32 · 40 · 63 A | 30 mA (25 to 63 A) · 300 mA (25, 40, 63 A) | 240 V~ | 35.6 mm |
| 4P (3P+N) | 25 · 40 · 63 A | 30 mA (25 to 63 A) · 300 mA (40, 63 A) | 415 V~ | 71.2 mm |
Rating and the associated circuit breaker
A residual current circuit breaker (RCCB) does not protect against overloads: it must be protected by a circuit breaker upstream or by the breakers of the circuits downstream. Its rating is chosen at least equal to the current that can flow through it, in practice that of the incoming breaker or the sum of the circuits it feeds.
In a home, circuits are spread over several 30 mA RCCBs: see the guide circuit breaker and RCCB for a villa.
Testing your RCCB
Every residual current circuit breaker has a test button. Pressing it must make it trip: this checks its mechanism and should be done regularly. If it does not trip, have it replaced by an electrician.
Frequently asked questions
What is the difference between a 30 mA and a 300 mA RCCB?
The 30 mA device protects people against electric shock. The 300 mA device protects the installation against insulation faults and fire risk, but not people.
When is a type A RCCB needed?
For circuits whose electronics can produce leakage with a DC component: notably the washing machine and the cooktop, following NF C 15-100 practice.
Does a residual current circuit breaker protect against overloads?
No. It must be combined with a circuit breaker. Only an RCBO combines both functions.
Which TSL3-63 ratings are available?
25, 32, 40 and 63 A in 2 poles; 25, 40 and 63 A in 4 poles, at 30 mA and 300 mA depending on the reference.
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