Some manufacturers do offer a complete solution that meets all the requirements in the UK.

Sometimes, this can be easier than trying to effect an installation from a kit of parts.

As we move into a situation where we have a number of “SMART” or “green energy” products and so on, all of these disparate items need to work together as a complete system.

The setup and integration of the management systems may well be more difficult than the “electrical problems” (I use quotes here because, of course, they are only “problems” for domestic-scale installations because they are new concepts … those familiar with large infrastructure, healthcare, etc. installations will already be familiar with supply change-over and battery-backed supplies).

This is quite a good link as it indicates the actual output is limited to half the battery capacity as a product of discharge current and voltage (ie 0.5 C if I'm using the correct terminology) and it would appear that the warranty is either 10 years or earlier if the declared kWh charge/discharge cycles have been used up…..

I don't know the UK price but it would be good to work out the cost per kWh extracted from the battery using the declared capacity and 90% DOD cycles compared to present domestic costs of around 18p per kWh.

Regards

BOD

Sorry Andy, whilst this would at first appear correct, you also need to disconnect the supplier's neutral from the installation for a number of reasons. Failure to do so can render RCD protection inoperative (or could cause nuisance tripping) … and that may well be important because of the reduced EFLI in island mode.

I disagree that the entire installation needs to be disconnected from the supplier's N - rather just the portion that's supplied by the embedded generation needs to be galvanically isolated. Just as if we had a UPS that was serving just a few critical items - the remainder of the installation remains connected to the (dead) grid supply during power cuts.

   - Andy.

AJJewsbury: 
 

Sorry Andy, whilst this would at first appear correct, you also need to disconnect the supplier's neutral from the installation for a number of reasons. Failure to do so can render RCD protection inoperative (or could cause nuisance tripping) … and that may well be important because of the reduced EFLI in island mode.

I disagree that the entire installation needs to be disconnected from the supplier's N - rather just the portion that's supplied by the embedded generation needs to be galvanically isolated. Just as if we had a UPS that was serving just a few critical items - the remainder of the installation remains connected to the (dead) grid supply during power cuts.

   - Andy.

Yes, that is true, the Neutral must be disconnected from any part of the installation supplied by the backup.

Not all UPS work like that, as we discussed in another thread recently. If you take your supply at LV, you can't rely on the distributor's N-E link, and of course you can't just “earth the neutral” upstream of the UPS to fix that without disconnecting the Neutral.

So in that respect, UPS vs backup are identical.

The IET CoP covers both options - “backup” for part of an installation, and “backup” for the whole installation. There still has to be a means of switching L & N to the distributor's supply from the backup system, and forming N-E connection.


Anyway, the point I was making, that others make to me, is that you're not “isolated from the distributor's Neutral” if you keep the distributor's means of earthing connected - it's the Neutral conductor that needs separating, NOT the whole system from the distributor's means of earthing (and neutral).