230V AC control

[BruceS]

I have a new inverter/charger on the houseboat & am looking for the better way to run it to reduce power bill for using grid power.
I'll try my hardest to explain the 'situation' & how I want it to 'run'.

The shore power comes into the boat & eventually goes to the inverter/charger after going through the switchboard/circuit breaker/rcd.
There is a 'branch' off before it gets to the inverter, through another circuit breaker for running very high demand equipment like air conditioner etc. This is live with either the genny going or shore power coming in.
On my last inverter/charger(Outback) I had the controller (Mate) on the helm which I could simply turn AC power on or off at the inverter & that allowed power to still feed the higher drawing units.
This new one (Schneider Conext SW) only has the ability to put it in "standby" which then feeds all power requirements straight through from shore to whatever is on.
What I want is to shut off power to the inverter so it switches to battery/inverter for normal requirements but still allow power for the high use jobs.
OK, to do that I need to cut the power after the switchboard but just before the inverter.
My idea is to install a relay there.
I'd love to activate the relay from the helm if I could.
I have a 40A 3 phase relay in my possession. It is 3.5v to 32v DC activated. I have 24V down there.
Now I need either a wire to a switch on the helm or ???
I found a wireless operated relay like on a garage roller door that might/should do the job well.
I'm after some advice about the 3 phase relay.
I can either ..........
1. Just put the active wire on one phase line.
2. Put Active, neutral wire on two phase lines.
3. Put active, neutral & Earth on 3 phase lines.
4. Split the active into 3 lines on the 3 phases to lessen the load on each phase line? (& bypass directly the neutral & Earth wires) If there is a load of 21A will it put 7A on each 'line'?

Will a SSR do the job or will I need a heavy duty magnetic type switch like on big electric motors?
OK, David, Jon & others....... thoughts & advice please?

[T1 Terry]

Connect the active and neutral to line 1 and line 2 on the relay, but join the earth wires together routed around the relay ..... it is illegal to switch an earth circuit. You need a 4 pole relay if you want to switch the earth link from the house power supply so it doesn't trip the shore power RCD ..... I'll let someone else draw that one up for you

T1 Terry

[supersparky]

I reckon T1 is on the money. But I would do a few test runs with the wireless relay to ensure it switches without any issues before you do the wiring mods.

[T1 Terry]

If it was 12v there is a much easier solution, a "Finder" contactor that can handle 25 amps and fits in a single Dinrail enclosure, we use them to control the inverter/chargers with our T1 Lithium control system to prevent cell over voltage damage.

T1 Terry

[jon_d]

Bruce, second attempt of writing.

Study Fig 3.1 AS 3001:2008 Dave has a copy.

All that would be needed is a change over switch and wire it in to a couple of the required circuits as per the standard..

[BruceS]

Thank you everyone for your input!
I've got a wireless relay coming that will run on 24v DC which is close by & I can use that on the outside of the shunt. It is well within it's capabilities to operate the 3 phase relay.
No one got around to suggest if splitting the single phase active wire through 2 of the phase switches would split the load and maybe get the SSR to last a bit longer with an easier life?
Do I REALLY need to switch the neutral wire?

[jon_d]

No one got around to suggest if splitting the single phase active wire through 2 of the phase switches would split the load

If you divide the active, you need to divide the neutral. So a 4 pole switch is needed.
Also, make sure the relay has a centre off position. (break before make). You don't want one source feeding the other.

And always get a professional opinion.

Do I REALLY need to switch the neutral wire?

You really do need a professional if asking this and if wiring it to the As standard with a MEN link.


Bruce, worst case is, the shore power goes out and somehow your set up is backfeeding the grid. Just enough to fool the solar inverters on the local roofs. And then everything is live when it shouldn't be. Please be careful.

[BruceS]

Yep, got it.
The relay is not a changeover switch it's just an on or off switch.
In fact to do as I'm 'wanting' I could just as easily install a 42A male & female plug & pull it apart!
Thought was to make the change remotely.
I'll run it past Rodney the local boat power guy.
Thanks!

[native pepper]

If it was 12v there is a much easier solution, a "Finder" contactor that can handle 25 amps and fits in a single Dinrail enclosure, we use them to control the inverter/chargers with our T1 Lithium control system to prevent cell over voltage damage.

T1 Terry

You can get them in 230v x 25amp AC from the UK and probably in Aus.

[T1 Terry]

If it was 12v there is a much easier solution, a "Finder" contactor that can handle 25 amps and fits in a single Dinrail enclosure, we use them to control the inverter/chargers with our T1 Lithium control system to prevent cell over voltage damage.

T1 Terry

You can get them in 230v x 25amp AC from the UK and probably in Aus.

Is the driver 230vac? The ones we use have a 12v driver but they switch the 230vac @ 25 amps .... tried on on 24vdc and it didn't last long Wasn't intentional either, just a mis-placed wire in the control box and that was all she wrote .....

Jaycar sell a DPDT 240vac relay driven by 24v or another model driven by 240vac. If the common was wired to the house load, the N/C side to the inverter and the N/O side to the shore power, that could be switched using 24v or auto switched when shore power was available by looping the wiring from the N/O terminals to the relay drive terminals. When shore power was supplied the relay would switch and connect the N/O terminals to the common terminals supplying shore power to the inverter powered house power circuits, when shore power was lost, the relay would drop back to the non power position and the shore power to common terminal link would be broken but the N/C to common link would be made so the inverter again powered the inverter designated house load circuit.

T1 Terry