Linking an inverter to the van’s 230V internal sockets

[autorouter]

The motorhome socket wires plug into the inverter output socket. The existing wire to the sockets you just disconnected from the mcb probably won't reach far enough, so the junction box is just to extend it so it reaches the inverter output.

All the switching happens inside the Renogy inverter. It switches automatically so that the inverter output socket is powered from either the hookup mains or the inverter mains.

 

[Moto GBR]

I have looked at the rear of the Sargent unit and think I have identified the socket wires as per picture. Thinks this is on a ring circuit as there is two white wires going into the rear of it.

Do I cut these two wires or just one of them and add a junction box enabling me to run a feed from the outlet of the inverter?

I have the inverter installed and linked to the battery, I am going to run the 240 input lead to a socket in the MH. I have a plug / flex from the outlet of the inverter, I just need to know where to link into. Sorry to ask so many questions.

TA Steve

 

[Googlebot]

There is a thread in my signature where I did this with lots of help on here. It’s automatic as soon as I switch the inverter on.

 

[MisterB]

I was thinking more like this. For an inverter like the Renogy with a built-in transfer switch.
View attachment 927772

That's very very similar to my setup - works perfectly!

 

[Moto GBR]

Thanks for the input but I do not want to change my consumer unit. I have the Renogy inverter that automatically change over from mains to 12v. Just need to know how and where to wire the sockets only in.

TA Steve

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[autorouter]

I have looked at the rear of the Sargent unit and think I have identified the socket wires as per picture. Thinks this is on a ring circuit as there is two white wires going into the rear of it.

Do I cut these two wires or just one of them and add a junction box enabling me to run a feed from the outlet of the inverter?

Ring circuits are not used in motorhomes, they are always radial. Ring circuits are a quirk of UK domestic house wiring.

Looks like there are two radial circuits, the white wire from the MCB1 and one of the wires (the white one) from MCB2. There's different ways of doing this, but I think I would connect both wires feeding the sockets to one side of a junction box, and the other side to MCB1. Then both wires, ie all the sockets, will run from MCB1.

Doing that, you will end up with one wire from MCB1 to the inverter mains input. Then the two wires to the sockets joined at a junction box. Then another wire from the junction box with a plug on it, to the inverter mains output socket.

MCB1 is a 10A breaker (C10 written on it). You will have to make sure that the total load from all the sockets doesn't exceed 10A (ie 2400W). If this is a problem, and you really want to, you can change the C10 MCB for a C16 MCB like MCB 2. But I get the impression you want to leave the consumer unit unaltered. It's quite common when camping to have to think about which mains devices you can use together, and which have to be used separately. The hookup post is only 16A maximum, so you can't use more than 16 x 230 = 3680 watts in total anyway.

Another option is to move the yellow heating wire to MCB1. The 10A limit should be enough for that, I think the heater is 1800W max. Then use MCB2 (C16) for the two sockets wires, that will put the limit up to 16A.

 

[Moto GBR]

Thats fantastic, Makes sense now.

Appreciated.

TA Steve

 

[Moto GBR]

I have managed to have ago at installing the wiring from the inverter into the MH sockets.

I have a junction box with the wires from the MCB, wires to the MH sockets, wires from the inverter output and wires to the inverter input all connected together.

When I plug into EHU all runs off the mains, I can switch on the inverter and all still runs off the mains. When I shut the mains down with the inverter still switched on, it then runs off the inverter, which is what I am aiming for.

I have a slight problem as when I then switch back to the mains, it does not kick back in. I have to shut everything down then plug the mains back in. Does anyone know what the issue may be?

TA Steve

 

[MisterB]

Sorry, but I am a little confused, why would you want to run the inverter with the mains connected? I have the 3000kw Renogy inverter but only turn it on when needed. The pass through facility still works with the inverter turned off and mains connected.

Mine is wired so that not every socket is 'live' when 'off EHU' but when on EHU because of the pass through they are all 'live'.

I don't use mine for emergency power provision if the EHU fails, I use it when off EHU only. Is there a specific reason you want to use it that way?

 

[Moto GBR]

I thought it would change back to mains if the power ever failed then kicked back in?

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[autorouter]

I have a junction box with the wires from the MCB, wires to the MH sockets, wires from the inverter output and wires to the inverter input all connected together.

I don't think that is right. The wires from the MCB should be connected to the wires to the inverter input. The wires from the inverter output should be connected to the wires to the MH sockets. The way you said it, it sounds like all four sets of wires are all connected together, which is definitely wrong.

You need two junction boxes. Like the diagram in post #28. But with a second junction box between the MCB and the Inverter 240V IN.

You should not connect the inverter output to the EHU mains. Their waveforms are not synchronised. If the wave peaks coincide, it's OK. If the wave peaks are opposite, there will be a voltage of over 600V between them. Do you feel lucky? Keep the inverter output and mains input well separated.

 

[autorouter]

I thought it would change back to mains if the power ever failed then kicked back in?

It depends on the 'priority setting' of the switch inside the inverter. Usually it's 'grid priority', ie the power comes from the grid (hookup) and if that fails, the inverter takes over. Then when the grid power comes back, it takes over automatically.

It sounds like you want to run from the inverter, and if that power fails, switch over to grid power. I don't know enough about Renogy inverters to tell you if it's possible to change the priority of the internal switch, maybe someone who has one will know. If it was an external transfer switch, you could just swap the two inputs. It's unusual to want inverter priority rather than grid priority.

Edit: reading your post again, I think I misread it. You want the standard priority setting, ie grid priority. That's exactly what the Renogy inverter should do, if it's wired up properly. Maybe if you sort out the wires as I said above then it will work as you want it to.

 

[Moto GBR]

So helpful, thanks very much

 

[Moto GBR]

I have rewired as per instructions (I think?) seems to be working ok. I am away to the Drax event tomorrow so will see how it goes.

Thanks again for the helpful input.

TA Steve