The right inverter for battery storage and some other Qs

[sharpener]

Yes, many people install a 4-way garage unit as a convenient way of housing these bits. If you are upgrading anyway you might also think about

(i) a Surge Protection Device

Would the 4-way unit accommodate everything,ie:
-RCD100mA + Curve C 25A breaker.
-Surge protection Device?

Do you have an example of a suitable set including above or what SPD shall i buy?

I used one of these https://www.tlc-direct.co.uk/Products/MK6820S.html. You will need two extra ways in the CU for it, there are some 1-way ones also https://www.tlc-direct.co.uk/Products/WYNMT2SPD3W1.html which would then all go in a 4-way CU but more expensive. See note above re swapping N and E connections if you have a TT system.

AFAiK TLC sell all the rest of the bits, so do CEF and most wholesalers

Do I still need AC isolator if I have above?

Yes unless you can find a lockable RCD because the MCS/IET spec requires it to be two pole and lockable.

(ii) a bypass switch to connect the house to the incoming mains if the inverter is out of commission

Does this mean that using a standard connection if something goes wrong with inverter I won't have power at home from the grid?

If the whole house is fed through the inverter as with my Victron then yes. If the inverter is installed in a grid parallel fashion then maybe no. But it will not then give you the UPS capability because the inverter will trip on loss-of-mains. An ideal solution would be to have a separate relay which reverts to the grid on inverter failure but I have not implemented it because of cost and space considerations.

[ducabi]

SPD (I'm on TNCS):
https://www.tlc-direct.co.uk/Products/MK6820S.html
4way unit:
https://www.tlc-direct.co.uk/Products/CPDD041MS.html
Type C MBC (25A at leas):
https://www.tlc-direct.co.uk/Products/CPB1032C.html
2P isolator switch:
RS-link

That's all I need to connect inverter (excluding PVs and batteries)?

I'm a bit worried of loosing power when inverter switches off. What people generally do if their inverter breaks?

[Oldgreybeard]

FWIW, all main switches, RCDs, MCBs, RCBOs etc are lockable by design. Lock-off kits are carried by all competent electricians (and are a mandatory requirement for safe working), and are so cheap that I have two or three of them just so I can be absolutely sure that someone doesn't turn a supply back on whilst I'm working on it. This is one of mine, with a small padlock through the hole to stop it being removed from the main switch it's locking off:

[Countrypaul]

Are those parts are from different manufacturers, or just different badges on them? I thought the CU and components had to be from the same manufacturer to compy with certain regs.

Just out of curiosity, when the RCD/etc has to be lockable, would ocking the CU not count ?

[Oldgreybeard]

Are those parts are from different manufacturers, or just different badges on them? I thought the CU and components had to be from the same manufacturer to compy with certain regs.

Just out of curiosity, when the RCD/etc has to be lockable, would ocking the CU not count ?

The Type Approval for compatibility in a consumer unit relates wholly to the location and design of the busbar. Very common for different manufacturers to have the busbar height varying from that of their competitors, some even use unique plug in bus bars (Crabtree Starbreaker, for example). When wiring non-busbar connected DIN rail mount components in the same DIN enclosure there are no issues at all with TA concerns, as with discrete wiring there's no potential for there to be a compatibility problem.

Very often there is a need (as in the case above) to use DIN rail mount parts from different manufacturers inside a DIN rail enclosure. The example above is a DP isolator switch in the same enclosure as a MID compliant energy meter. All discretely wired inside, with no busbar to create any issue.

[ducabi]

Are those parts are from different manufacturers, or just different badges on them? I thought the CU and components had to be from the same manufacturer to compy with certain regs.

Just out of curiosity, when the RCD/etc has to be lockable, would ocking the CU not count ?

I wasn't aware it needed to be hence so many questions from my side. List updated:
I guess isolator switch no longer needed as it's in the unit.

SPD (I'm on TNCS):
https://www.tlc-direct.co.uk/Products/MK6820S.html
6way unit:
https://www.tlc-direct.co.uk/Products/MKY5708SMET.html

RCD 100A 100mA because it's not in the unit:
RCD 100A 100mA
Type C MBC (25A at leas):
https://www.tlc-direct.co.uk/Products/MK8732.html

[Oldgreybeard]

TBH, I'm not sure why most PV installations use big and clunky industrial rotary isolators rather than domestic isolation switches. Maybe one of those things where someone used one in a demo rig right at the start, maybe an industrial electrical chap used to using them, when MCS first came about, then everyone assumed that the regs demanded their use. The reality is that any isolation switch of the right type and rating can be used, and the lock-off requirement can be met as long as a lock off kit fits the isolator (not yet seen one it won't fit, TBH).

I can't see any issue with locking off within the CU, it's what I have been doing to make sure someone doesn't accidentally turn something back on for years now. Only slight issue with lock off kits is that you need the lid of the CU to open wide enough to get a screwdriver in to tighten the locking screw on the lock-off (that screw is made inaccessible when the padlock's fitted).

[ducabi]

So, the setup is sorted thanks to all of you!

What do I do if I need to bypass inverter when it stops working and I still want my fridge running?

[Countrypaul]

So, the setup is sorted thanks to all of you!

What do I do if I need to bypass inverter when it stops working and I still want my fridge running?

I presume this is when it is on the UPS side of the inverter - cant you just plug it into the normal grid side sockets?

[sharpener]

That's all I need to connect inverter (excluding PVs and batteries)?

I'm a bit worried of loosing power when inverter switches off. What people generally do if their inverter breaks?

You need to check how your planned inverter will be installed, RTM. A few other things...

Are those parts are from different manufacturers, or just different badges on them? I thought the CU and components had to be from the same manufacturer to compy with certain regs.

Just out of curiosity, when the RCD/etc has to be lockable, would ocking the CU not count ?

I wasn't aware it needed to be hence so many questions from my side. List updated:
I guess isolator switch no longer needed as it's in the unit.

SPD (I'm on TNCS):
https://www.tlc-direct.co.uk/Products/MK6820S.html
6way unit:
https://www.tlc-direct.co.uk/Products/MKY5708SMET.html

RCD 100A 100mA because it's not in the unit:
RCD 100A 100mA
Type C MBC (25A at leas):
https://www.tlc-direct.co.uk/Products/MK8732.html

Your electrician will have his preferred sources for all this stuff. The RCD is Type AC, not sure this is current recommendation, OGB will know. The SPD needs to be fitted within ?0.5m of the intake so it may be better sited elsewhere.

The CU you are proposing has space for 6 other modules - do you need that many? It comes with a Main Switch, provided you can lock that, the isolaor on the inverter, the RCD or the CU cover then IMO you do not need a separate isolator though one often (?usually) sees them in installation pictures.

There are many ways of skinning the cat. I fitted a new isolator to match the one on my PV inverter circuit as it was cheaper than buying a new RCD (or the big locking kit).

FWIW, all main switches, RCDs, MCBs, RCBOs etc are lockable by design. Lock-off kits are carried by all competent electricians (and are a mandatory requirement for safe working), and are so cheap that I have two or three of them just so I can be absolutely sure that someone doesn't turn a supply back on whilst I'm working on it.

I don't know about all. The RCD on my inverter cct is an old Crabtree 3-wide one repurposed, I have not found a lock to fit it, certainly the 2-pin one I bought for the purpose doesn't. A comprehensive kit like this https://www.cef.co.uk/catalogue/product ... ockout-kit would have cost more than the isolator. My interpretation of the standard is that it should be lockable with a padlock without any particular accessory kit. Other than that I agree, the rotary isolators look clunky in a domestic setting.