# Inverter Wiring with Auto Switching to EHU



## teemyob

Hello,

Finally managed to get around to fitting our inverter and contacter (been meaning to do it for 2 years!).

Same set up as our last motorhome, here are some pics.

For now, it is mainly so we can use all the sockets for things like TV's Chargers and such like. Will be great to pull up on and Aire/Stelplatz and use electricity without needing EHU.

Notes:

(A)

I had to replace the existing Consumer unit as the....

Heating
Fridge
A/C
Sockets
Battery Charger

All ran off one 16A MCB

(B)

I Have wired in the Habitation A/C but as yet the current inverter is nowhere near powerful enough to run it.

I have also oversized some cables to cope with an upgrade to say a 3kW inverter.

(C) The System does have 2 x 220ah Batteries, but I might reduce this to just one.

Can anyone think of anything I have missed or done wrong?

TM


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## Jezport

Looks like a 100% professional job. Which nightschool class did you attend, I will sign up :wink:


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## teemyob

*Wiring*

Thanks Jezport.

I tidied the wiring up after the photos!.


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## Techno100

Yup same contactor :thumbup:
I bought a 200watt sterling pure sine off ebay for £121.99 ONLY I received a 350 watt one for the same price  Result!! There are no 200watts in stock until August so upgrades are being dished out


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## Jezport

*Re: Wiring*



teemyob said:


> Thanks Jezport.


When are you doing mine? :wink: I have the same silly consumer unit in my Frankia.

If you are intending running the aircon on an inverter later I would keep both batteries if I was you.


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## teemyob

*Re: Wiring*



Jezport said:


> teemyob said:
> 
> 
> 
> Thanks Jezport.
> 
> 
> 
> When are you doing mine? :wink: I have the same silly consumer unit in my Frankia.
> 
> If you are intending running the aircon on an inverter later I would keep both batteries if I was you.
Click to expand...

I have wired the Habitation Air-Conditioner in for two reasons.

For cooling use on the move only, with the Engine running. We do have cab climate control but in very hot weather, the rear passengers will be able to use the habitation a/c. We have solar panels and a 220ah Alternator. So when I get a bigger inverter, we can use it.

In the meantime, we can make use of the LED's on the Dometic B2200 that we could only use on EHU.

TM


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## Jezport

*Re: Wiring*



teemyob said:


> Jezport said:
> 
> 
> 
> 
> 
> teemyob said:
> 
> 
> 
> Thanks Jezport.
> 
> 
> 
> When are you doing mine? :wink: I have the same silly consumer unit in my Frankia.
> 
> If you are intending running the aircon on an inverter later I would keep both batteries if I was you.
> 
> Click to expand...
> 
> I have wired the Habitation Air-Conditioner in for two reasons.
> 
> For cooling use on the move only, with the Engine running. We do have cab climate control but in very hot weather, the rear passengers will be able to use the habitation a/c. We have solar panels and a 220ah Alternator. So when I get a bigger inverter, we can use it.
> 
> In the meantime, we can make use of the LED's on the Dometic B2200 that we could only use on EHU.
> 
> TM
Click to expand...

On my aircon I can select a fan mode which does not use the compressor. I have a 500w Durite pure sine wave inverter and can run the fans to cool our van. I am not sure how much current it uses but may be you could do the same with your setup.


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## teemyob

*Fan*

Yes, the fan will run from the inverter too. Might help airflow.

The cab A/C works well, just sometimes when we have 6 on-board and the weather is very hot, the passengers will be able to use the extra cooling if they wish.

So the new Twin MCB's serve separate circuits.

Only from EHU are:

Fridge
ALDE Mains Heating
Battery Charger

From EHU or Inverter

All 240v Sockets
Dometic A/C


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## Jean-Luc

My simple idiot proof 'manual' changeover setup.

I have a supply cable (extended) from the mains consumer unit terminating at a socket fixed close to the inverter.

I have a 13amp plug fitted to the cable (extended) which originally ran from the consumer unit and supplied the 'house' sockets (current through this setup not likely to exceed their rating even when on an EHU)

When on EHU plug is in socket connected to consumer unit
When off EHU plug is in inverter socket 

'House' sockets are powered either way, buy never the twain shall meet.

Siiimples


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## teemyob

*siiimples*

Thanks JL

It is the Simple things in life that confuse my cabin crew, hence the upgrade/mod.

TM


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## teemyob

*siiimples*

Thanks JL

It is the Simple things in life that confuse my cabin crew, hence the upgrade/mod.

TM


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## eddievanbitz

Looks a great job. Did you remember to put an additional RCD on the output of the inverter?

So many people don't!

Eddie


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## teemyob

*Somone*



eddievanbitz said:


> Looks a great job. Did you remember to put an additional RCD on the output of the inverter?
> 
> So many people don't!
> 
> Eddie


A-Ha, someone has spotted something.

No I have not put and RCD On the Inverter output!

Just an RCD?

I have space in the Contacter housing and had considered a 16a RCBO wired through for the inverter output.

TM


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## eddievanbitz

We always install an RCD on the output of the inverter, but don't install an MCB

For us it is just belt and braces knowing that our customers are safe whatever daft things they do.

It was something we spotted had moved into the boating world about three years ago as a safety precaution so we adopted it ourselves.

Job neat job though

Eddie


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## Techno100

Surely that will only work if the neutral of the inverter output is at earth potential? many outputs are centre tapped and 115volts on each pole.
Tell us more Ed?


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## clive1821

yes and a lot of inverters will not let you bond the neutral to earth, well you can but you upset the triacs, but I'm sure its tested with an rcd tester to make sure the rcd is doing something when a earth fault is devloped.....


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## Techno100

My radial of 2 socket outlets is simply acting as an extension cable to the socket on the inverter via the auto changeover. As all the equipment I plug into these sockets is double insulated or SELV I don't believe an RCD is required even if you could get one to function.


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## eddievanbitz

The Neutral phase of Victron inverters for example is connected to the chassis


> The neutral wire of the AC output of this inverter is connected to the
> chassis.
> This is to ensure proper functioning of a GFCI (or RCCB) to be installed in the
> AC output of the Inverter.
> The chassis of the product must be connected toground, to the frame (of a
> vehicle) or the ground plate or hull (of a boat).
> Procedure
> The terminal points are indicated clearly. From left to right: "PE" (earth), "L" (phase) and "N"
> (neutral).
> 4.4 Optional


 Mastervolt and Sterling recommend the same installation of an RCD on the inverter output.

http://www.victronenergy.com/upload...Compact 2000 - rev 01 - EN NL FR DE ES SE.pdf

It is surprising how many people when you talk to them think inverters are fairly harmless as they "really only 12 volt DC" 

Anyway, time for me to go home so sweet dreams!

Eddie


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## Techno100

Not for my Sterling 350 watt :lol: and it has no earthing terminal.


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## clive1821

well a slight dissagrement andy, but yes as well, in real life the rdc is there for protection in the event of an earth fault... and if you are in contact with the live conductor with respect to earth or theses days the cpc, yes the inverter will kill you if are across the live, so the official line i would have to say yes put an rcd in line with the output of the inverter, in if in doupt with the output interface of the inverter I put a 1 : 1 transformer in to icolate the inverter form the bonding neccessary to make the rcd function..... but in real life the rcd is an option you can do without, its the same as people putting a rcd on their generators and they will not work for the very same reason of no bonding..... just my view, when installing and protecting you need to understand how the devices work and then understand the risks...


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## Techno100

Yes Live to earth but if there is no earth you can't get a belt :wink:


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## eddievanbitz

Techno100 said:


> Not for my Sterling 350 watt :lol: and it has no earthing terminal.


 :lol: True!

Now I am def off home :wink:

Good night

Eddie


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## clive1821

yes Andy, good comet.. but there's always the capactive effect of the case of the inverter to the 240volt supply and you still can in cases get a fair belt from that, so its best just to make sure the neutral and the earth are at the same point, hence the mention of bonding to earth and takeing it back the the common supply point... its splitting hairs yes but its different when you are installing equipment for a person and it has to be correct.....


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## eddievanbitz

clive1821 said:


> just my view, when installing and protecting you need to understand how the devices work and then understand the risks...


Or, from a commercial point of view, if, a detailed, in depth, knowledge of every product you sell becomes unrealistic, follow the advice of the manufacturers.

When we fit an expensive inverter and the handbook states that there should be a RCD fitted and we don't our customers soon get jittery.

If we then tried to argue that Mastervolt, Sterling and Victron were actually wrong and we Van Bitz were right I suspect we wouldn't get very far :lol:

There are lots of things that we "have" to do that in reality we probably "wouldn't" do if we didn't have to.

My Father used to say to me "Don't do as I do, do as I say"

Cheers

Eddie


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## Techno100

It's all about how it's being used and I have no trailing wires and anything that is trailing is SELV like the vacuum charger or phone charger. The TV has a transformer and is velcro'd to the wall behind the TV and the mains lead shortened to about 150mm. People don't have to imagine hazards that are not there.
If I sold my van I would remove my kit and it would be back as manufactured for the next owner.


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## clive1821

yes Eddy quite agree with you most of the expensive inverters you talk of have some sort of 1 : 1 transformers in the output stages and hence the earth bonting point corectley is at the the common earth point as it should be and good working practices etc.... but if you have a good look at most of the chepo inverters that dose not come into play and will still kill you!! good topic to discuss good night to you  Its just different when you have to install and be liable for any issues..... in a privavate case it matters not.... but I do have to be carefull what I say and people like me have to the same thing......


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## teemyob

*Earth*

Still divided re the inverter earthing!?


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## Techno100

I would stick to manufacturer instruction/recommendations.
personally I'm happy that my 350 watt pure sine is safe and all wiring protected against damage/contact.


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