Changing from 110v to 240v ? (1 Viewer)

[snooky]

Looking at a motorhome that's still 110v.
How much does it cost to get it changed to 240v ?
Is it a big job or can it be done easy as I've not had anything to do with this sort of thing.
Thanks

 

[tacr2man]

You would be better asking on sister forum RVOC
There are a couple of answers or so .

 

[treetops1]

Why would you want it changed to 240v

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[Richard n Ann]

Because UK and European EHU is 240v?
Pretty useless as it is unless it has a transformer which is wasteful.

 

[snooky]

Why would you want it changed to 240v

To use all my 230v items of course. What is the benefits of leaving it 110v ?

 

[Lenny HB]

Normally fit a transformer so that all the existing appliances will work. If you require 230v sockets just fit where need and and feed them from a consumer unit with an RCD and circuit breakers.

To convert existing appliances to 230v would be an expensive operation not cost effective.

Some of the RV boys should be along soon to give you more detailed info.

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[Wildbill]

i would just fit new consumer unit and replace plugs wiring where kneaded

 

[olley]

Most of us just fit a tranny to convert 230v to 110v, you need 110v unless you convert everything to 230v like your fridge, microwave and battery charger. As for 230v some have a whole new circuit fitted, others convert all the 110v sockets to 230v, and others just have a few 230v dotted about. Mine came with a new circuit supplying around 5-6 sockets, so I have both 110v and 230v sockets which can be handy if you have any yank appliances like a toaster, grill or kettle etc. I have a small consumer unit with an RCD and two mcb's, one for the 110v and one for the 230v.

I would think to have a leccy fit a tranny with consumer unit and say six sockets in the RV you would be looking at around £3000. Wired properly the tranny can be reverse fed from the 110v genny to give you 230v.

 

[snooky]

Ok cheers. What tranny would be best suited ? Anyone got a link to a decent one that would be suitable?
Cheers

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[olley]

Can't think of one at the moment, go on rvoc.co.uk which a sister site to fun, its for American motorhomes, and ask on there, someone will have a link.

 

[snooky]

Appreciate that ! Thanks

 

[tacr2man]

It is possible to buy bidirectional transformer that will do both ways
so you can power everything from hook up or on board Gennie .
It depends on how you want to configure things , which you need to discuss with a suitably experienced electrician .

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[jockaneezer]

I saw a programme ages ago where a guy was doing up an Airstream caravan, he just reversed wired a yellow site transformer into the loom, it looked a bit dodgy to me, I bet @pappajohn would know if it's safe or not.

 

[Richard n Ann]

I saw a programme ages ago where a guy was doing up an Airstream caravan, he just reversed wired a yellow site transformer into the loom, it looked a bit dodgy to me, I bet @pappajohn would know if it's safe or not.

Ahh... I saw that programme and it was in the Back of my mind I'd seen a tool transformer used. Should be safe enough, that's after all what they're made for.
I used one in reverse once on a building site to plug my 230v battery drill charger into, had to keep it hidden or I'd have got a right bollocking

 

[olley]

Yellow Site trannys aren't continuiosly rated, some do use them but its not a good idea in my opinion.
Not sure you could use them in reverse on an rv. Site trannys are two phase, 55v on each phase, the genny on an rv is 110 single phase, so you would be feeding 110v down a single line, I don't think that would work.

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[Robin McHood]

Transformers by their nature are bi-directional. Site transformers (the yellow GRP encased type have two ratings normally. A continuous rating and an intermittent. The headline advertised one eg 3kVA is generally the intermittent rating.

It is possible to reconfigure a site transformer to produce USA style 115v.
However the earthing needs to be reconfigured by someone who knows what they are doing. US regs have grounded neutrals at the distribution box only. As I have no personal knowledge of how RVs are wired as regards generators/distribution boxes GFI's etc I'm not going to advise, other than to say, don't do it yourself!

 

[tacr2man]

This is the sort of thing that gives you most flexibility
http://www.ebay.co.uk/itm/VOLTAGE-C...729052?hash=item3a8faf3b5c:g:h8AAAOSwq7JULeNB

 

[pappajohn]

Because UK and European EHU is 240v?
Pretty useless as it is unless it has a transformer which is wasteful.

But is a necessity if you convert to 230v.
Battery charger, fridge freezer and any air con units are all 120v so you still need 230v hook up to 120v appliances transfomer.
The usual route is to install a new 230v system alongside the existing 120v system.
You could then run sockets and a 230v charger from it but the fridge freezer and air con would be prohibitively expensive just to get rid of the 230v/120v transformer.

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[pappajohn]

Ahh... I saw that programme and it was in the Back of my mind I'd seen a tool transformer used. Should be safe enough, that's after all what they're made for.

No it isn't.....
Builders yellow box transformers are designed for short intermittent use, not constantly for days on end.
They may be plugged in all day on building sites but with no load applied for much of the time.
In my opinion, running one 'reversed' is not ideal when proper SAFE converters are available.

 

[Richard n Ann]

No it isn't.....
Builders yellow box transformers are designed for short intermittent use, not constantly for days on end.
They may be plugged in all day on building sites but with no load applied for much of the time.
In my opinion, running one 'reversed' is not ideal when proper SAFE converters are available.

I looked them up yesterday they have a continuous rating that is lower than the labeled rating. I agree about the reversing, I did it because I'm a rebel

 

[Robin McHood]

@snooky. The recommendation to keep the 110v circuits by @pappajohn is probably a wise one. A suitable stepdown transformer to suit the 110v load is easily available though not necessarily cheap. Then running a 220v separate circuit for those things that 'have' to be 220v is fairly straightforward. You could use a site type transformer suitably rated for the 220/110v conversion with the secondary suitably reconfigured as I posted above, though there are wall mountable cased transformers which is what I would use. I would emphasise though that you should not do this conversion work yourself. It would be too easy to create a hazardous situation.

I am speaking with my professional hat on here. I have no idea of the other posters qualifications but I am a registered Eur Ing and a long time Member of the Institute of Electrical Engineers with way too many years as Chief Electrical Engineer. I also know what I don't know!

Regarding site transformers, as I posted above, they ARE rated for continuous use but the headline rating is usually the intermittent one

This sheet from Carrol & Meynell, (one of the biggest transformer manufacturers in the UK) for wall mounted cased transformers shows the ratings for a number of different capacities. Note the difference between the Intermittent rating and the continuous rating.

http://docs-europe.electrocomponents.com/webdocs/017e/0900766b8017e5ee.pdf

Here is one for site transformers (the yellow block type)

http://docs-europe.electrocomponents.com/webdocs/017e/0900766b8017e4bf.pdf

They also manufacture specific UK/US transformers in the same block type construction. These are not isolating transformers but auto transformers and as they are manufactured for this purpose would not invalidate the profuct certification.

http://carroll-meynell.com/uk-to-us-supply-conversion

Transformers CAN be run either way round but the associated wiring and protection has to be changed to suit, not a DIY job. We often used to do this to supply European contractors 220v equipment from an American built rig supply of 110v Phase/Neutral.

The other item that can sometimes cause problems is that the US supply frequency standard is 60Hz not 50Hz. Not a problem offshore or on ships because we have been using 60Hz standard for decades at 110/220/440v and up. It was, I believe a NATO standard post the Second World War.

This can affect some frequency sensitive equipment, not in a good way.

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[snooky]

Ok thanks for all your knollage. I'm back to looking for another RV because this one was over 40% on my damp meter in several places when I got told it was bone dry.