Powering the consumer unit (house) from AC Battery Sockets

fearrchair

I have the following setup as shown below, at the moment when the Grid goes offline l have been able to use the discharging batteries DC sockets to obtain 230V.

I have been thinking of adding more DIY batteries etc to add more capacity, 20.48kWh at present (16kWh 20%).

If there was another switch fitted and a cable ran from the AC Battery supply right had socket could it be toggled to switch the mains to the consumer board from the meter Grid supply to the batteries.

Or would this be too much of a load.

It would be like a changeoverswitch but with the PV panels still disabled when off grid. Or does it still need a ground that l hear if the changeover switch was fitted fully 1000-2000 coat etc.

the_amazing_raisin

So you'd have another breaker in the CU which is wired to the backup power supply from the inverter?

This switch would be open normally and if there's a power cut you'd open the breaker for the main power and close the breaker for the backup power?

While that's technically feasible, I'm pretty sure it won't fly. For one thing ESB Networks won't support it, there need to be a changeover switch to ensure the mains is isolated before the backup power is connected. With the setup you described there's nothing stopping anyone from connecting the backup power into the mains by accident

Another issue is that I'm pretty sure you'll only isolate the live that way and the neutral has to be isolated as well in a changeover switch

In terms of overloading the inverter, that's really up to you to manage. I think the backup power is limited to 5kW which is likely enough to manage all the small consumers and have enough left to run the kettle or air fryer and possibly even a heat pump or small electric heater

fearrchair

I understand yes a switch fitted that would allow the batteries to feed into the CU, the panels and fireman switch could still stay disabled as its an issue. I would be okay on the load as I have a 6kW inverter. I suppose with with fitting a changerover switch running the wire over I would be as well to have wired it for a full correct changerover that allows panels to work and the inverter to power off the CU as normal. You would see these videos of people adding in sub boards off the main CU taking a few sockets and lights and heating onto it. Probably gets complicated then.

the_amazing_raisin

https://www.boards.ie/discussion/comment/123356747#Comment_123356747

I feel like if you're going to that level of hassle you might as well get the full CU wired to the changeover switch and reenable your panels in a power cut

Its allowed as long as the switch is within a few metres of the meter box or front door (I think 2 metres is the limit)

No matter what I'm pretty sure you need to isolate the neutral and earth as well, which may require a new meter tail

I'd stop and have a think about what the goal here is. If you're concerned about power cuts lasting more than a day or so then a full changeover switch is probably a good idea

However for outages lasting a few hours it might just be enough to power the kitchen sockets, internet router and maybe a heat pump if it's allowed. I got a bit of a raised eyebrow when I mentioned that to my installer so it might be to much power. You'd probably be looking at a sub board for that

Another possibility is going full prepper and doing both, so you've uninterrupted power for some essential things (fridge/freezer, alarm, CCTV or something) and can changeover the whole house is required

the_amazing_raisin

To give some background, there's actually 2 forces driving the panels be isolated in a power cut and they have different requirements

The first is ESB Networks, when there's an outage then they need to be sure there's no generators feeding into the grid. Otherwise some poor ESB engineer might get barbecued when he's fixing whatever substation is having issues. For this reason the house needs to be fully isolated via a changeover switch before any backup power can be connected to the house's supply

The second is the fire brigade, they always turn off the power to a house before going in to ensure there are no live wires that may pose a danger to firefighters. This is why the fireman switch is required close to the panels and why backup power is generally limited to a small selection of consumers

Again, a changeover switch is allowed but it needs to be somewhere easy for firefighters to access and clearly marked

fearrchair

I was talking to my brother since and he was saying arent you only repeating yourself running a wire over to the CU when the inverter and batteries are already in its circuit etc and connected, whats the point in that ha, and its a bit silly what I was saying. My setup is inside and I can already run power to the kitchen appliances which are only in the adjacent room from those Battery AC sockets. I could increase the battery capacity or have them charged fully if I knew an outage was coming, extension leads ready, should go a long way. The proper changer switch would be best way than any other half measures … I seen a social media clip the other day Darren something and he was saying as well don't override firmans switch similar to what your saying that if they did have to come out and pull out the main fuse and theres still power in the house they could stand back and let it burn especially if theres solar and the insurance wouldn't pay out either. Heard from a local electrician theres hes seen a good few dangerout connetions where people had wired in changerover switches for generators and in one case the connetion was live on the generator side as well.

graememk

https://www.boards.ie/discussion/comment/123358167#Comment_123358167

"What's the point in running a second cable for the backup supply"

Safety, idiot proofing.

Changeover switches in properly, there will be no way to back feed the grid, it will be interlocked with no room for human error. If you try to make a cable do double duty it opens the door for mistakes in the changeover process.

eiritated

Is there a definite regulation on the fire officer safety?

I plan to fit a suitably obvious “kill switch” ie a failsafe normally closed switch that once broken would stay that way and it would stop the inverter dead.

I want to do the right thing so plan this would be in the meter cabinet but I’ve seen no guidance on position or labelling and the electrician says that ESBN have not guided on this yet?