Updated 30 May 2017

This article shows the sizes and lengths of electric supply cables for caravans and motor homes legally required in Australia and NZ. 

Supply cables for caravans – the basic requirements

Prior to 2008 some restrictions on supply cables for caravans ensured they were acceptable for other usages then under revision. Without those restrictions, supply cables for caravans would have been legal (and safe) for some uses, but not others. The revised requirements thus removed that risk. Furthermore, they resulted in more approved lengths.

The new supply cables for caravans requirements are set out in Table 5.1 of AS/NZS 3001:2008 (as Amended in 2012).

The relevant part is set out below. The lengths and sizes shown relate to typical supply cables for all RV use. There are, however, restrictions if used for loads such as large electric motors etc. These are unlikely in any RV use.

Cable rating

Conductor area

Length

10 amp

1.0 sq. mm

25m

10 amp

2.5 sq. mm

60 m

10 amp

4.0 sq. mm

100 m

15/16 amp

1.5 sq. mm

25 m

15/16 amp

2.5 sq. mm

40 m

15/16 amp

4.0 sq. mm

65 m

Supply cables for caravans (and general use). This is Table 5.1 of AS/NZS 3001:2008 as Amended 2012. Extract reproduced by courtesy of Standards Australia.

Supply cables for caravans – you shall not join cable together

Their is an overall purpose behind specifying lengths and conductor sizes of supply cables. It is to ensure circuit breakers will, at any cable used at its maximum cable operate within 0.4 second. That time is necessary to save lives.

If current, or cable length is exceeded, circuit breaker operation slows. That is why joining supply cables end-to-end is dangerous. It is now thus also illegal.

Supply cables must be one of the approved types and of one unbroken length. 

Supply cables for caravans – 10-15 amp adaptors

The restriction on co-joining cables applies particularly to (always illegal) 10-15 amp adaptor leads. These, in effect, enable 15 amps to be drawn through cable too small to carry it. If used, an associated circuit breaker may not trip in time to save life.

Also totally out are double adaptors to enable more than one caravan to use the same socket outlet. This has always been potentially dangerous. This too is now illegal. If someone plugs your cable into a double adaptor, attempt to resolve its removal amicably. If that fails, however, have the caravan park manager remove it for you.

The above requirements are not hard. Your cable must comply with the standard. You must use only one cable to connect your vehicle to the supply. If its too short, either obtain a longer one or move the caravan closer. The only alternative is to forgo using that site-supplied power.

None of the above is negotiable. The requirements are clear, and legally mandatory. Personal opinion and forum ‘interpretation’ is irrelevant.

Supply cables for caravans – for the technically minded

New supply cable rules relate to RCD (Residual Current Device) and circuit breaker protection. The RCD compares current flowing in active and neutral. It cuts off the supply if any imbalance is detected. Circuit breakers monitor for excess current flow.

Electric shock reaction relates to time. To save life, current must be cut off within 0.4 second. Faster acting units are used in hospitals etc. To ensure this, a cable’s resistance to flow must be within specific limits. If the resistance (impedance) exceeds that limit, the circuit breaker may operate, Its operation, however, is slowed. This is why supply cables must never be joined end to end.

Earthing is still required. It carries initial fault current before the RCD/CB cuts off supply.

Supply cables for caravans – 10/15 amp issues

Early caravans used appliances that drew more current than now. That required caravan parks to have 15 amp socket outlets. It is, however sometimes needed to use a caravan where there are only 10 amp outlets. A 15 amp plug will not fit. It has a larger earth pin. To get around that people might file that pin to fit. Or make an illegal 10-15 amp cable.

There cannot however be a weak link in a chain of safety. That includes not pulling 15 amps through plugs, cables and connectors designed to carry 10 amps. It’s thus like a 10 tonne cable and a 15 tonne winch.

You can, however, legally use a 10 amp supply cable for caravans if all related bits are also changed to 10 amps. That includes: inlet socket, RCDS and circuit breakers. Doing so thus prevents over 10 amps being drawn. Currently, no supplier makes a direct 10 amp socket inlet replacement. Clipsal’s 56 A1310 surface mounting 10 amp inlet socket is larger. But legally acceptable.

The Amp-Fibian

The Amp-fibian is another legal alternative. It is a cable with a 10 amp inlet plug and a 15 amp outlet socket plus an inbuilt 10 amp circuit breaker and RCD. It acts as a supply cable but, legally classified as a Portable Socket Outlet Assembly.

AMP-FIBIAN Products

The Amp-fibian 15-10 amp adaptor . A standard supply cable for caravans is plugged into the receptacle (left) that is then sealed by a waterproof cover.

If seeking to power an RV at home, you could have a licensed electrician install a 15 amp power outlet socket.

(The supply cables for caravans requirements apply now also to their general use.)

Supply cables for caravans – tagging

Occupational Health, Safety and Welfare Regulations include provisions for protecting working staff. These rules provide for the regular inspection and testing of electrical equipment. This activity, known as ‘tagging’ is generally enforced by caravan parks and RV Rally organisers.

That it is needed was typically shown by an Australian Caravan Club meet in 2014. There, of 212 supply cables for caravans tested, 84 (40%) failed to pass. Five had broken earth wires within the plug or socket. And 24 had cross polarity conductors. (The standard re testing is AS/NZS 3760).

Caravan park owners and managers, and rally organisers, are responsible for the safety of their employees. Also, as a ‘controller of premises’, of other employees who may access the facilities. There is also a general duty of care to those staying in or visiting.

None of the above requires users’ cables to be tagged. Some caravan parks, however, enforce that. Based on Public Liability requirements, they require extension leads (and power boards) to be tested and tagged every 12 months. There is no legal requirement for them to do so. That may, however, be conditional for insurance cover. They can, in any case, enforce this as a condition of entry.

For cable taggers – check local Yellow Pages (or Google).

Supply cables for caravans – outdated standards

Long retired electricians may not be aware that fundamental safety approaches have totally chnaged. This, particularly, is true of earthing. Source documents are: AS/NZS 3000:2007, and the RV-related AS/NZS 3001.2008 (both Amended in 2012).

Supply cables for caravans – further information

Further details about supply cables for caravans etc, is in Caravan & Motorhome Electrics, Caravan & Motorhome Book, and the Camper Trailer Book. My books on solar are Solar That Really Works (for cabins and RVs) and Solar Success (for home and property systems).

 See also Caravan Buyers Guide – a best seller by Andrew Woodmansey and edited by Collyn Rivers – Bio.

Disclosure:

The above is sourced from Standards Australia’s documents (noted above)) I have extensive practical and theoretical background in electrical equipment and systems. I am not, however, a qualified electrical engineer, nor licensed electrician.