Different earthing query

Having just had solar panels and a battery fitted, Yes, there is an isolator to disconnect the incoming mains supply from the house, thus allowing the battery to feed the house - while it can.

The earth side of the installation is unaffected

But with your earth not relying solely on the supply (Regulation

I would say install a second circuit to the house with a limited number of Schuko sockets located in strategic places then if there is a power failure plug the equipment in using UK>EU adapters. This would put it beyond doubt :-)

That regulation includes the word "automatic". This is, as I said, a manual switch. My earth does not rely on the incoming cable.

The "automatic" in "Protection by automatic disconnection of supply" means things like fuses, MCBs and RCDs.

He'd need a generator change-over switch, probably using a pair of ganged contactors which would have mechanical and electrical interlock between them.

That statement probably requires some qualification since it won't be true in all cases.

For properties that are already TT (no suppliers earth, local earth rod, and all circuits with adequate RCD protection to ensure disconnection in the event of an earth fault even when the earth loop impedance is far above typical suppliers earth levels.

For any TN supply (i.e. TN-S and TN-C-S) you are not supposed to rely on the earth connection during a power interruption. (since you don't necessarily know *why* there is an interruption)

So in those cases you would need your own earth provision in addition to the suppliers earth, and the conditions about the install being adequately protected to run TT applies. (This is less of a problem with

Indeed, like this:

There are earth issues. However you do it, unless perhaps you distribute ELV, which would be a nuisance. Either do a lot of research and be prepared to break the rules or hire an electrician. Look how complicated EV chargers are. (Though earth is not the only consideration with these, of course.)

Well, all I'll say is I'm glad he is not in my terrace of houses. 6KW for how long one wonders.

There are a lot of these DIY things for this use on E-Bay apparently, and there are second user slightly used Lithium batteries around as well that are still good from this use point of view. Personally even if I could see now, I'd be loathe to DIY this sort of thing. Wonder what happens if some big load suddenly switches on? Brian

As an aside, mate of mine, retired engineer thinks the fire risk presented by lithium ion batteries indoors (say in the loft) to store electricity from solar panels is too high. Do you think he is being overly risk averse?

I suppose you could argue there is some risk, and there is no reason they have to be in the loft... so you could mitigate by putting them somewhere else (in an outbuilding for example!) or just make sure there are interlinked heat and smoke alarms close by.

The battery fire risk ought not be significant on a well designed battery with a proper management system that monitors individual cell voltage and temperature. Whether your chinesium has those things is another matter.

This sounds like someone wanting to reinvent the wheel. There are plenty of commercial inverters with solar panels and batteries. I've recently changed my original Sunnyboy grid tied inverter to a 3.6kW Sunsynk model which has a 5.2 kWh battery. To avoid disturbing my original stage 1 FIT I'm keeping the same panels until the existing FIT conditions expire. Currently all my solar panel output is either converted to 230 volt ac, synchronised and fed back into the consumer unit or the generated power fed into the battery for storage until required. If the battery is full the excess power is exported to the grid. The battery charging is controlled by a monitoring system The inverter is capable of far more than my simple application. It can take power at times of cheap rates, store it and export to the grid at a profit at other times of day or feed to the household load. During a grid outage it has a facility of supplying limited power to essential circuits from the battery via the inverter. From idly perusing the instructions earthing changeover is carried out automatically.

Discussing this in the pub the other night someone said he's considering getting batteries put in the greenhouse. If it burns down it's not the end of the world, and the waste heat will help the tomatoes.

Andy

I'd have thought greenhouses (and indeed lofts) might take some batteries outside their recommended temperature range.

"My" battery is fitted on an outside wall of the house. Operating Temp is specfied as -10°C to +55°C. Storage: -30°C to +60°C

If you like your tomatoes char grilled :-)

Yes, good point and well made!

I had in mind that some solar system batteries come with a narrower range for optimum performance (including long life) than for safe operation. E.g. Tesla Powerwall 2 has an operating temp of 0 - 50 C but an optimum temp of 0 to 30 C is recommended.

"When outside this recommended temperature range, charge/discharge power may be reduced and Powerwall will utilize its thermal control system more frequently to maintain battery cell temperature which will reduce the energy efficiency of the system. Systems operating off-grid for long periods (>4 hours) in cold weather systems may need to curtail PV, and reduce energy used for pre-conditioning."