# Using invertors and existing mains wiring



## 101600 (Oct 30, 2006)

I have been thinking about doing this for a while, I am ex-electrician out of the game for over 5 years and I am a little rusty so please point out any drastic mistakes I have made here.

I want to use the inverter with existing wiring while not on mains hook up I have done a wiring diagram using a contactor with a 240v coil and a auxiliary contact to power the mains wiring when not on hook up, thus when it is plugged in even if I forget to turn the inverter off via the switch it will no longer be powering the van.

I should point out I wont be using the kettle etc its for TV only while not on site and only for short periods of time.










What do you think???


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## Bryan (Aug 9, 2006)

As you will only want it for a TV, for short periods, why not use an individual invertor? The sort that plugs into a cigarette lighter socket. About £15.

I am interested in the 'better' option you outline in your post, but my solution would need to include the onboard generator (220v).

Regards
Bryan


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## olley (May 1, 2005)

Hi Rob looks ok. to me, but why not use a double throw contactor and save money and space.

Bryan if you have an auto change over switch on the genny then it will simply disconnect the incoming feed whether its mains or inverter if you started the genny.

Olley


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## trevorf (May 16, 2005)

Hi Rob,

Looks fine to me too. You can tell you have out of the game for a while though, The nominal voltage is now classifies as 230V not 240V :lol: :lol: 

Bryan, there is a problem with invertors plugged into cigarette lighter sockets.
Many european vans, mine included, have cabling which is too thin the handle the current drawn from the 12V system. My van has a 12V cig lighter socket in the TV cupboard but my 300W invertor did not work as it could not draw enough current from the wiring. I had to run thicker cable direct from the leisure battery to the TV cupboard to get it to work.

Trevor


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## Bryan (Aug 9, 2006)

Good point, Trevor.

My van is american but I will consider the wiring if my inverter (as yet unused) does not work.

Bryan


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## 101368 (Oct 12, 2006)

roboughton said:


> I have been thinking about doing this for a while, I am ex-electrician out of the game for over 5 years and I am a little rusty so please point out any drastic mistakes I have made here.
> 
> I want to use the inverter with existing wiring while not on mains hook up I have done a wiring diagram using a contactor with a 240v coil and a auxiliary contact to power the mains wiring when not on hook up, thus when it is plugged in even if I forget to turn the inverter off via the switch it will no longer be powering the van.
> 
> ...


Stick in an extra contact to disconnect the 12v supply to the inverter might be a good idea. Stops it flattening the batteries when it's not powering anything.


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## teensvan (May 9, 2005)

To be on the safe side I wired in two separate sockets from our 350 watt inverter. Positioned one socket in the T/V conpartment , and one in the other end of the lounge area so as able to run laptop ect. No problems in 2 years.

steve & ann ----- teensvan.


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## Snelly (Aug 20, 2005)

olley said:


> Hi Rob looks ok. to me, but why not use a double throw contactor and save money and space.
> 
> Bryan if you have an auto change over switch on the genny then it will simply disconnect the incoming feed whether its mains or inverter if you started the genny.
> 
> Olley


Agreed... Thats how I did it on my Euramobil and it worked brilliantly. Just have to make sure you exclude the battery charger and fridge from the circuit, otherwise potentially you could overload your inverter.


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## 101600 (Oct 30, 2006)

WebAgents said:


> As you will only want it for a TV, for short periods, why not use an individual invertor? The sort that plugs into a cigarette lighter socket. About £15.
> 
> I am interested in the 'better' option you outline in your post, but my solution would need to include the onboard generator (220v).
> 
> ...


I want a solution that wont get in the way the indivdual invertor ineeds to have large cables and i have a invertor in place already this is a cheep option and i have access to all the parts. I guess this would work with a genny if you wirred it in to the supply for the 240.


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## 101600 (Oct 30, 2006)

trevorf said:


> Hi Rob,
> 
> Looks fine to me too. You can tell you have out of the game for a while though, The nominal voltage is now classifies as 230V not 240V :lol: :lol:
> 
> ...


lol yeh yeh 230 240 yeh yeh i still pull closer to 240 when testing than 230 lol.

I would not put anything more than a 150watt on a *** lighter and besides i would still have to run cables for it.

i can situ it all nice and neat and out of the way. most of it is in place already its just a matter of adapting it.


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## 101600 (Oct 30, 2006)

emgee said:


> roboughton said:
> 
> 
> > I have been thinking about doing this for a while, I am ex-electrician out of the game for over 5 years and I am a little rusty so please point out any drastic mistakes I have made here.
> ...


good idea i can probably get that from the auxiliary if i plan it right if not just a simple contactor would be fine.

Thanks for all your advice guys i am going to do this as it think it is a good way off supplying the van.

any sparks got any ideas on if the contactor would be ok if it was on for long periods? i cannot think of any such long periods that one is left on for in my experience as they were always on and off every few hours or so.

advice appreciated

Rob


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## 101600 (Oct 30, 2006)

Snelly said:


> olley said:
> 
> 
> > Hi Rob looks ok. to me, but why not use a double throw contactor and save money and space.
> ...


not sure how i would do this yet but i guess it would involve adding a new supply to both from a new breaker by the incoming main hook up and supplying the fridge and battery charger.

what would you recomend

sorry for so many replies but i get confused easily when replying to so many people in one post


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## Jean-Luc (Jul 21, 2005)

I would recommend a human contactor. Let me explain what I did. First I disconnected the output cable for the socket circuit from the MCB and fitted a 3 pin plug to the cable end. Next I wired in a 3 pin mains socket to the output terminals of the same MCB. Lastly I fitted the inverter close by (Battery also close by). 
Now this is how it works. 
If I have a mains supply I plug the cable serving the sockets into the socket fed from the MCB, if I am not on mains and require mains voltage I change the plug to the socket of the inverter. The benefit if this arrangement,apart from its simplicity, is that it is imposable to cross connect the inverter and mains.
I should add that my Rapido has separate MCB's for the sockets, charger, fridge and heating so only the sockets will 'pull' from the inverter.


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## olley (May 1, 2005)

Hi rob overheating shouldn't be a problem, when I did the 3 phase for our shop I put a 100amp 3 phase contactor in, when we go at night I flick a switch and it drops out turning all 3 phases off. So its on all day from 9-9 

Only problem we had was when we lost a phase (fault in the road) and it went berserk and burnt its contacts out.

I have wired my inverter up as jean-luc, so I plug the EHU either into the mains or into the inverter (its 1800watt got it of good ole GT) and I fiitted a switch to turn the battery charger off.

Olley


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## BigWhiteBox (Jan 8, 2007)

I may be missing something but if the mains is connected does that cause the contactor to pull in thus extending the mains to the van electrics. 
If that is the case what stops the invertor from trying to operate at the same time? 

If the two are on together - they won't be for long!!!! 

If the aux contacts are used will they make/break before the hookup mains is switched through, just a few milliseconds could be fatal for the invertor.

I would use a simple changeover switch with an isolated central position. An interlocked dual switch would be better but that would make it a bit larger.

Dave


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## 101600 (Oct 30, 2006)

BigWhiteBox said:


> I may be missing something but if the mains is connected does that cause the contactor to pull in thus extending the mains to the van electrics.
> If that is the case what stops the invertor from trying to operate at the same time?
> 
> If the two are on together - they won't be for long!!!!
> ...


if you look at the wiring diagram when power is applied via mains hook up the invertors power is dropped via the auxilary contactor tha mounts on the top of the main contactor, i will also have a switch on the invertor so it is not on when not needed all i wanted was a way to make sure both circits were isolated when either is in use or not available if you get what i mean.

as for the time delays well maybe i should fit two contactors and do away with the auxilary put the mains hook up on a 10 second delay timer and have the invertor pull out before the mains pulls in i will try to re-write the diagram and show what i mean


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## 101600 (Oct 30, 2006)

olley said:


> Hi rob overheating shouldn't be a problem, when I did the 3 phase for our shop I put a 100amp 3 phase contactor in, when we go at night I flick a switch and it drops out turning all 3 phases off. So its on all day from 9-9
> 
> Only problem we had was when we lost a phase (fault in the road) and it went berserk and burnt its contacts out.
> 
> ...


i thought as much its just i have not used one in such a long time. i know issues can arrise from such a system and i will always try to turn the invertor to the off position before i plug in to main hook up, i just want a system where by i am not duplicating wirng in my van when i already have it and have a cheep and simple way to use it. it is only like a distribution pannel for a refrigeration system but on a smaller scale.

I think i will sorce my auxilary contactor as i already have the main on and give it a go. I will let you all know how i get on when it gets a bit warmer to get under the van and pull wires.


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