Hi The use of a 240v t0 110v step down transformer is still a common practise by some importers In fact one Aus transformer maker openly advertises a transformer for that purpose & claims a clause in the standards allows such use Such has never been approved by the relevant standards :AS/NZS 3001:2008
The use of this product in this manner is considered dangerous.
Appendix C 6.11 of AS/NZS 3001:2008 is a New Zealand only normative requirement [referred to on the makers site) that refers to isolation transformers being used in lieu of RCDs for personal protection on external socket outlets of caravans that were manufactured after 1 April 1993.
The clause is not recognised in Australia, and more importantly it does not allow for isolation transformers to be used as a step down transformer for supply to the whole caravan in New Zealand or Australia.
Beware if you are importing or purchasing or have an import from a dealer
Anyone on this forum have such a setup??
Peter
-- Edited by oldtrack123 on Thursday 8th of December 2011 03:31:00 PM
-- Edited by oldtrack123 on Thursday 8th of December 2011 06:07:48 PM
It does seem a bit strange to import vehicles fitted with 110VAC equipment for use in Australia doesn't it? If it is legitimate to to actually use these vehicles fitted with 110VAC equipment though, how would you be able to use them with an RCD? It wouldn't work as far as I could see, due to the isolation effect of the transformer? Is this right oldtrack?
[1]It does seem a bit strange to import vehicles fitted with 110VAC equipment for use in Australia doesn't it?
[2] If it is legitimate to to actually use these vehicles fitted with 110VAC equipment though,
[3] how would you be able to use them with an RCD? It wouldn't work as far as I could see, due to the isolation effect of the transformer? Is this right oldtrack?
Hi Troopy
-[1] It,s done mainly with used units, saves a lot of money not replacing all the electrics,but it seems some do import new units as well set up for 110v
[2] NO it is not legit to use those 110v appliances unless they have an Aus approval[very unlikely]
[3] That IS why they are dangerous, any RCD fitted would be inoperable.
The standards simply do not allow step down transformers or non approved appliances ,switchgear, etc
Any one with such a set up should seek qualified advise from their STATE ELECTRICAL SAFETY OPFFICE
Not just from some electrician!!
Anyone on this forum have such a set up??
Peter
-- Edited by oldtrack123 on Thursday 8th of December 2011 06:06:22 PM
-- Edited by oldtrack123 on Thursday 8th of December 2011 06:10:24 PM
What would be he situation if an auto transformer were used?
One big problem is a lot of these trasformers are of the auto transformer type where the secondary winding is actually half of the primary winding. With one of those it is easy to get a situation where the active is running at 110 -130 V above earth and the neutral is 240 V above earth. You have then a situation where 240 V power is running through wires with insulation built to carry only 120 V.
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PeterD Nissan Navara D23 diesel auto, Spaceland pop-top Retired radio and electronics technician. NSW Central Coast.
Thanks Peter & Peter, It was only a thought bubble.
One wonders why it's not mandatory (and enforced) for imported RVs to meet the same standards as locally made units.
Hi Jim
Actually it is mandatory to comply with Aus standards as verified by ESOs & a member of the relevant standards commitee
Enforcement is the real issue in these days of so "called selfregulation"
The greatest load of crap ever thought up & that comes from someone who has had the experience of being QA manager with a very large engineering co
All the appropriate boxes get ticked & signed , & THAT is accepted in good faith
As long as the paper work says it complies , that is all that is generally required ,as verified to me by three ESO I've had direct contact with on this matter
It will be interesting to see what develops further on this particular matter, as the standards members are quite concerned due to safety aspects
The interesting thing is that an AUS transformer supplier has reworded his sales speil & now is using a totally irrellevent clause of the standard [& only applicable in NZ] in an attempt to maintain his sales
HE claims to be an electrical engineer
This is a wide spread problem in the electrical & many other industries & not just with imported vans etc
Some of the problem is no doubt due to lack of knowledge or failing to understand the requirements
.Some deliberately try to find loopholes
The worst thing is that some who should realy know the reqs /rules do not
THAT inclues some ESO's staff as I have found out personally & from some other forums' members
End of rave
Peter
-- Edited by oldtrack123 on Friday 9th of December 2011 10:25:15 AM
It used to amaze me some of the cr*p that some of our engineers used to come out with, when I was working for a large aircraft manufacturing company a while back. They seemed to have the attitude that because they were engineers they could contravene standing rules and regulations at a whim, without any dispensation from higher authorities. Incidentally, most of the mains powered equipment we used in that job was 110VAC, run off stepdown transformers simply because everything was designed and built in the US.
Just strap the neutral on the 240V side to one end of the 110V secondary and then you have a non-isolated system with full RCD protection.
HI dorian
Sorry that still does not comply with the standards
& if you look carefully is definately not a wise thing to do
You could end up with 350v between each active
AND how do you have the mains neutral linked with something supplied via an extension lead ????
But what could be a solution if approved is to make a correctly phased earthed neutral connection on the secondry of the transformer & fit an additional RCD to the secondary BUT it has the same problem as above
But that in effect is no different to an auto transformer, which definately is not approved
There is still the problem of non approved appliances & a suitable Aus approved RCD.
Peter
-- Edited by oldtrack123 on Saturday 10th of December 2011 09:06:25 PM
-- Edited by oldtrack123 on Saturday 10th of December 2011 09:22:46 PM
