WoEF - No Overload Protection in Caravan

[Slovett]

I carried out a WoEF on a Caravan this morning. Older Toyota Hiace Van, 16A Inlet, 1x PDL RCD Power Point and 1x 10A Double Power Point. However there was no SwitchBoard and therefore no Overload Protection. An RCD Power point was down stream from the 16A inlet, and another Double power point was down stream from the RCD power point. It still had what looks like the original WoEF attached to the inside of the Van - Dated 1991. It also had an existing WoEF, which Expired last month but all the Electrical Workers Details had faded off.

I failed the WoEF because of the non existent OverLoad Protection, but the previous WoEF has made me think - Is there retrospective clause that I don't know about, that once upon a time this was Legal? Or do all new WoEF need to comply with current standards??

Photos attached for reference

Thanks

[TPower]

I would’ve failed it also. So far as I know you can only issue a Woef in accordance with appendix C of 3001.

Clause C6.4 clearly states over current protection shall be fitted to match supply lead & fittings, with exception to caravans incorporating a neutral/earth link.

[AlecK]

Exactly.

However it's possible this unit is old enough to have originally had a N-E link that has since been (illegally) removed.
Under ECP 1 allowed the link to be at the first fitting if there was no switchboard;
and that arrangement was not uncommon ('cos it was cheaper)

[PeteRig]

Also ECP1 clause 3.3.1 mentions that the fitting closest to the appliance inlet where the link can be (if no swb) must be labelled appropriately.

[Slovett]

Thanks guys. I've told the owner he will need to get an Electrician to install a SwitchBoard with at least a 16A RCBO. Which leads to the next issue, there is basically nowhere where the switchboard will comply. There is nowhere that isn't obstructed by fixed furniture etc. The existing RCD Power point that is down stream from the 16A Inlet (back to back) is located right next to the head rest of the drivers seat. (You can't access it with the seat tilted back to the driving position).

"Why was it given a WoEF 4 years ago then??" - Don't you just love dealing with Caravans!

[AlecK]

One option would be to restore the unit to compliance with original rules; ie ECP1.
However that's only short-term solution; as eventually the WoEF system will change
so that N-E links have to be removed and RCd + current limitation has to be fitted before a WoEF can be issued.
(being written into next edition, but then needs to be cited by ESRs - and after that will take 4 years to get through the WoEF cycle)

But a SE2 or similar enclosure, big enough for 1 x RCBO, shouldn't be impossible to find a "readily accessible" place for, with cabling in surface casing / flexi conduit on surface.

[Slovett]

Yeah your right, its a pretty cramped set up, but he will just have to move / alter an area to fix a little surface board somewhere.

Thanks again.

[pluto]

The connectable installation details in this blog demonstrate that clarification on the configuration and overcurrent protection requirements for standard and simple connectable installations is required.

Remember that provisions for "connectable installations" have existed in the Electrical Wiring Regulations (EWR) 1935 (from the late 1930s by way of what was then known as an "Interpretation Circular" to the Electrical Wiring Regulations 1935), EWR 1961 and EWR 1976, ECP 1:1993, NZS 3019:2004 and AS/NZS 3001:2008. Over the years since EWR 1935 Interpretation circulars, the expression used as been "caravans", "relocatable installations", and latterly "connectable installations". There will be few electrical inspectors who will have carried out inspections and issuing WoEF over all this period. I have been worked on tools and design in the electrical industry for over 60 years, so I am aware of most of the requirements.

A "Warrant of Electrical Fitness" (WoEF) renewal only can be issued by electrical inspectors with a valid practising licence using the provisions of Electricity (Safety) Regulations 2010 regulation 78, which in turn require the use of AS/NZS 3001:2008 Appendix C.

AS/NZS 3001:2008 Appendix C has been purposely made wide enough to cover the vital safety outcomes for the Electrical Wiring Regulations requirements since 1935 through today's Electricity (Safety) requirements Regulations 2010 regulation 78.

However, care is required when considering the requirements for connectable installations constructed to earlier Electrical Wiring Regulations and Standards cited by recent Electricity (Safety) Regulations 2010.

There are some other essential points that all need to be considered when inspecting or modifying these simple connectable installations but will limit these notes' coverage to Overland protection, the Neutral to Earth link, and RCD protection the subject matter of this blog.

Overcurrent protection
I wish to draw electrical inspectors' attention who issue WoEF's of another method of overcurrent protection used in simple connectable installations, such as folding caravans.
In simple connectable installations, typically folding caravans, a SINGLE 10 amp socket outlet is or was the ONLY socket outlet provided. ECP 1:1993 provided for a single socket outlet without a switchboard (or splitter box). The overcurrent protection required can be provided without any additional fitting or device.

In simple terms, if the supply was obtained from an IEC 60309 16 A socket outlet in a caravan park or other location, this socket-outlet is fitted with overcurrent protection (MCB or RCBO), not greater than the socket-outlet rating.
The simple connectable installation is then connected by an IEC 60309 [ or BS 4343] 16 amp plug, the supply lead, through a 16 amp cord connector and 16 amp inlet plug on the connectable installation (if provided) and then directly to the SINGLE AS/NZS 3112 10 amp socket outlet.
The configuration is the electrical equivalent of an 16 amp plug and the supply lead supplying a 10 amp cord connector. The SINGLE 10 amp plug connects all loading it is NOT possible to overload the socket-outlet providing the supply, supply lead and its fittings.

Quoting from ECP 1:1993 clause 3.4.3; All fittings in a vehicle or relocatable installation and the associated supply lead (with the exception of the conductors described in sub-clause 3.4.2 of this Code [2.5 mm2 for 16 amp fittings] ) shall be protected against overcurrent by a protective device to limit the maximum overcurrent to a safe value and duration unless the current is limited by the nature of the fittings and electrical appliance in a vehicle or relocatable installation.
Quote ends
Note: A SINGLE 10 amp AS/NZS 3112 socket outlet is NOT possible to overload 16 amp fitting of the supply lead and fittings, so no additional fittings (MCB or RCBO) are required.

Quoting from NZS 3019:2004 clause 7.3.5 Over-current protection
Connectable installations, excepting caravans incorporating a neutral/earth link or connection, shall have overcurrent protection fitted to ensure that the maximum demand does not exceed the rating of the supply lead and supply lead fittings.
Quote ends
Notes
1. A SINGLE 10 amp AS/NZS 3112 socket outlet is NOT possible to overload 16 amp fitting of the supply lead and fittings, so no additional fittings (MCB or RCBO) are required.
2. NZS 3109:2004 covered the issue of WoEFs until Electricity (Safety) Regulations 2010, and AS/NZS 3001:2008 Appendix C was cited)

Quoting from AS/NZS 3001:2008 Appendix C (the current requirement of Electricity (Safety) Regulations 2010 Regulation 78).
Clause C6.4 Over-current protection
Connectable installations, excepting caravans incorporating a neutral/earth link or connection, shall have overcurrent protection fitted to ensure that the maximum demand does not exceed the rating of the supply lead and supply lead fittings.
Quote ends
Note: A SINGLE 10 amp AS/NZS 3112 socket outlet is NOT possible to overload 16 amp fitting of the supply lead and fittings, so no additional fittings (MCB or RCBO) are required.
However, if two or more 10 amp AS/NZS 3112 socket outlets are provided, fitting an additional current limiting fitting (MCB or RCB) is required.

Neutral to Earth link and RCD protection
All new connectable installations constructed since 1st April 2003 should be using the provisions of AS/NZS 3001:2001 and AS/NZS 3001:2008 and thus will have RCD protection and no Neutral to Earth link fitted.

Some additional RCD requirements in the upcoming amendment of AS/NZS 3001:2008 are expected to cater for caravans and motorhomes built in Europe and the UK to IEC standards. But this amendment has been considerably delayed by the joint AS/NZS Standards processes and the COVID-19 lockdowns over the last 12 months.

Caravans and Motorhomes constructed before 1st April 2003, unless modified or upgraded, will have NO RCD protection and be fitted with a Neutral to Earth link.

An Energy Safety Bulletin issued March 2003, "Upgrade of existing caravans and motorhome to AS/NZS 3001 requirements", gave recommended instructions for the voluntary modification of connectable installations, caravans, etc. motorhomes fitted with a Neutral to Earth link and the fitting of an RCBO to provide earth leakage protection. The instructions provided for the fitting of an RCBO connected upstream of the switchboard if it was impossible to fit an RCBO in Split-box type switchboards. The RCBO additionally provides overcurrent protection or limitation and RCD protection of the connectable installation.

It should be carefully noted that the transitional provisions of previous Electrical Wiring Regulations and the current Electricity (Safety) Regulations 2010 preclude the compulsory mandating of the retrospective modifications of the removal of the Neutral to Earth links and the provision of RCD protection in connectable installations, without a detailed amendment of the Electricity (Safety) Regulations 2010.

The modification recommendation became necessary due to new or upgrading of caravan parks having RCD protection for the supply to connectable installations from service pillars and prevented the obtaining a supply to the caravan or motorhome, without the illegal removal of the Neutral to Earth link.

The modification recommendation was carried out in many caravans and motorhomes as a voluntary upgrading at the time of a WoEF issue.

For simple connectable installations with a SINGLE AS/NZS 3112 socket outlet fitted, the Energy Safety modification recommendation would be achieved by removing the Neutral to Earth connection at the socket outlet fitting and to replace the SINGLE socket outlet with a SINGLE 10 amp socket outlet RCD. For many years, PDL socket outlet RCDs have complied with the type A RCD and the double pole switching requirements of Electricity (Safety) Regulations 2010.

ECP 1 provided for fitting the Neutral to Earth link on the SINGLE socket-outlet fitting used in simple connectable installations. The chassis earth connection was also required at the 10 amp socket outlet fitting (an alternative location is the 16 amp inlet plug on the connectable installation (if provided)). The 10 amp AS/NZS 3112 socket outlet also required labelling that the Neutral to Earth link was fitted at the socket outlet.

ECP 1 also provided for the use of RCDs to provide additional safety protection by fitting an RCD.

Quoting from ECP 1:1993 clause; 3.3.2 An RCD may be used to provide additional safety for electricity use in a vehicle or relocatable installation. In a caravan, the incoming neutral terminal of an RCD used for providing overall protection may be utilised as a supply neutral terminal for the purpose of establishing the link between neutral and earth.
Quote ends

I am returning to the subject of this blog.

The rejection of the connectable installation was the correct one. Still, if the double socket outlet fitting were removed, it would comply with AS/NZS 3001:2008 Appendix c.

The photos provided indicate to me that the installation is likely to have complied with the current requirements of AS/NZS 3001 Appendix C. The socket-outlet RCD is a very old PDL fitting with the socket surface being on a lower level from the socket control switch; that plate style has not been made after the early 2000s. The double socket outlet is of a more recent vintage, which indicates that the double socket outlet was a later addition.

Using the notes above, this would indicate that when the double socket outlet fitting was added, the connectable installation would have become non-compliant.

To make this connectable installation compliant, fit a 10 amp MCB is a separate suitable housing or use a single enclosure to contain an RCBO and three socket outlets.

[PeteRig]

A very good conclusion Alec and explanation, well done as always

[pluto]

Note it was NOT by AlecK but by PLUTO!

[JamieP]

That's not correct

Socket outlets are not current limited sources, yes a single item plugged in with a 10A plug on it should never be able to draw more than this but due to the fact we have multiboards and other devices many multiples of devices can be plugged in causing far higher than 10A loads

This is spelled out in 2.5.3.4 (b)(ii) of 3000 which talks about omission of overload protection

[pluto]

Be aware that AS/NZS 3000 only covers INSTALLATION wiring it does NOT cover appliances or other similar type loads temporarly plugged into socket outlets of a connectable installation.

That was the reasoning used when I help drafting of ECP 1 in 1992, and it has not changed since then.

[pluto]

Further to the above message
The application of AS/NZS 3000 series standards does not include the appliance series of standards which cover multi-boxes (EPODs etc) and double adapters the following applies;

greater than 3 socket outlet an overcurrent protection device rating can not exceed the max rating of the supply lead plug is required;

a 10 A AS/NZS 3112 double adapter are required to be marked "10 amp maximum load". What is missing in this standard is the need for consumer instruction (and understanding) that a double adapter can NOT be used when the total loading exceeds 10 amps.

[AlecK]

Pluto's very detailed history is - mostly - correct.

Not that it changes anything, as we'd already reached the conclusions that
a) the set-up was non-compliant and couldn't be issued a WoEF ; and
b) it may well have complied when installed, under ECP 1.
Pluto disagrees with conclusion b), and states that "ECP 1:1993 provided for a single socket outlet without a switchboard".
In several other places he emphasises: "SINGLE".

But ECP 1 had no such limitation.

The relevant wording was clause 3.3.1 "switchboards:
which stated that
"Every switchboard in a caravan shall contain a link between the earth continuity busbar and the supply neutral.
A caravan that does not contain a switchboard, shall contain a link between earth and neutral in or behind the fitting electrically closest to the caravan appliance inlet. the fitting shall be appropriately labelled."
There's nothing there - or anywhere else in the ECP - that restricts the 'no switchboard' arrangement in any way.

Therefore a configuration with two socket fittings (either singles or doubles - there were no quadruple sockets back then) would have complied; as long as a N-E link was in the first one, and suitable labelling was in place.


All the history of what rules were in place when is very complex; and can be interesting to see how they have changed.
But for WoEF purposes, the ONLY rules that matter are the current requirements for issue of a WoEF;
which are in App C.
C 6.4 requires either a N-E link or current limitation; and C 6.9 requires either a N-E link or RCD protection.

------------
pluto's right that a single socket would be, in effect, equivalent to an extension cord; and therefore would not require overcurrent protection.
But it was not part of ECP 1.; and it's simply not relevant to deciding how to get this particular unit into line with WoEF requirements.
The choices remain: either reinstate the link or provide both RCD protection and current limitation

JamieP is also correct that when a circuit includes sockets we can't use the exception that allows omission of overcurrent devices.
But again, that's a side issue; that only got dragged in by pluto insisting - incorrectly - that only a "single" socket was permitted.

And pluto's latest post wanders off into rules for EPODs & double adaptors
Absolutely not related to issuing WoEFs.

If were going to have discussions about those sorts of things, it should be in other threads and under aappropriately different headings