Caravan & Tiny House Switchboard Guide
Caravans, RVs and Tiny Houses are transportable structures and have to comply with AS/NZS3001:2008+A1 Relocatables. Here are a few tips to help you choose the right board.
Switchboards located on an internal wall with no water or dust hazard would not normally need to be IP rated (IP= index of water and/or dust protection). If the board is to be mounted externally or there is any dust or water issue the board would need to be IP rated, the higher the rating the more protection. Switchboards cannot be installed in bathrooms and there are other limitations - consult the installing electrician regarding zones within a wet area and the exact positioning of switchboards and sockets.
You may choose to select an IP rated board even when one is not required by regulation – it may suit the décor better, they are better constructed and have a door which is useful to protect & restrict access.
Enclosure or Switchboard?
An enclosure does not usually have busbars (fixed brass connectors used to terminate and join wires) which may be OK for a 2 way installation (just an RCBO for instance) because there may only be two cables. A switchboard (“distribution board”) with multiple busbars should be used where there are multiple cables to be terminated.
The most common board we sell is 6-way but often even a 2-way enclosure would be adequate to pass an electrical warrant of fitness (EWOF)). Most transportable installations are connected using a standard caravan lead with 16 amp (3600 watt) total capacity. You may think having a board with 10 circuit breakers is a good idea, but individual circuit breakers are only there for two reasons – one is to protect the cabling from overload (which the RCBO does already) and the other is for convenience – if you want to isolate a fridge separately or you do not want everything shutting down from one short circuit.
It is legal to have one 16 amp RCBO with no additional circuit breakers protecting the whole installation - if the wiring is all in 16 amp rated cable like it usually is (most commonly 1.5mm 7 stranded TPS) - a small 2 way enclosure could be perfectly adequate.
If for some reason the installation gets wired with multiple circuits all terminating at the board and you end up with 5-10 cables in your enclosure or switchboard, you would be wise to choose a 4, 6 or even 8 way board, occasionally even bigger in the larger spaces of an RV or a tiny house. But always remember a standard caravan connection is only 16 amps.
The device that is mandatory for all these transportable installations using a standard caravan lead is a 16 amp rated 30mA, Type A, RCBO (RCD with overcurrent & earth leakage detection) which must be marked as suitable for 230 volts AC.
A device now commonly installed is a load-limiting relay. This device protects critical circuits (fridge, internet, whichever you choose) – if one circuit is taking too much power the relay will automatically and temporarily turn off that circuit in favour of other circuits you choose as essential.
Changeover switches allow multiple power supplies – generator, supply lead, solar or inverter for example to be manually selected. Selecting which type of changeover switch may best be done in consultation with your electrician because the selection involves several options – current rating (in amps or kilowatts), mounting type (DIN rail or surface) and also the AS/NZS standard required for wiring it.