Bidirectional RCD socket or RCD FCU, are there any?

[ericmark]

On another forum someone wanted to fit balcony solar with an old Wylex fuse board with MCBs fitted, it was pointed out to have 230 volts outdoors it needs RCD protection, but I simply could not find a single FCU or socket with an RCD which says bidirectional.

 

[JohnW2]

On another forum someone wanted to fit balcony solar with an old Wylex fuse board with MCBs fitted ...

If the someone has money with which to buy 'balcony solar'' kit, it sounds that there are probably much more appropriate ways he could use the money to 'upgrade' his/her electrical installation

.... I simply could not find a single FCU or socket with an RCD which says bidirectional.

That's hardly surprising, is it? Until these recent discussions about what may become legal to use in the UK in the future, there was absolutely no reason why anyone would have wanted/needed a 'bidirectional' FCU/socket, so it would be fairly unlikely that anyone would have felt it appropriate to manufacture any ('speculatively'), wouldn't it?

 

[ericmark]

This

is the problem, solar panels are not expensive, so if someone has money with which to buy 'balcony solar'' kit, no longer means they have the money to do other things we would normally think should be done before starting. Rated 300 watts including inverter, it says made by Parkside, so assume German Lidi.

8 way consumer unit, £48.48, RCBO £28.14 so £273.60 for a CU populated and that is without SPD. By time fitted looking at over 3 times likely 4 times the price of the solar panel to have a CU which will work with it, considering Part P means £100 plus vat to DIY and get is pro fitted not much difference. He showed picture of the CU so to be within a reasonable price, only options to have RCD protection is a RCD socket or FCU, or the price means he will use without RCD protection.

It is very clear he is not fitting a new CU, not sure that he could even if he wanted, the question of rented of owner occupied has not been asked, for a tenant to swap a socket OK may be not quite what he should do, but likely he can get away with it, but to swap a CU is a non starter.

In the past this

was the answer, advert says type AC but picture shows

so looks like type A? It is not really any good as active type, but nothing shown on the data sheet shows it to be unidirectional so it may be OK.

But other than that can't find any RCD suitable for DIY fitting.

 

[denso13]

But other than that can't find any RCD suitable for DIY fitting.

It shouldn't be DIY at the moment though? It needs installed by an electrician.

 

[ericmark]

If a guy has bought plug in solar which can back feed into the grid, to then say he must spend 4 to 5 times what he has already paid to use it, is not going to work, tell him he needs to spend an extra £20 OK he may do it, but having paid £100 to then tell him he needs to spend another £400 to use it, the answer will be "go away", it works, so I am using it as supplied. Well it may be a tad more colourful!

 

[denso13]

it works, so I am using it as supplied.

It isn't fitted with a 3 pin plug though. If people want to break the law then there isn't much anyone can do about that.

 

[flameport]

, but I simply could not find a single FCU or socket with an RCD which says bidirectional.

Such a thing should never exist, as there are zero uses for it.

Hopefully no one will ever consider making one.

 

[plugwash]

You can get small enclosures into which you can fit din-rail mounted RCDs.

 

[ericmark]

You can get small enclosures into which you can fit din-rail mounted RCDs.

Agreed, but that is not really a DIY approach, I, and I am sure most people in this thread, have already got RCD protection on all circuits, so it is just a case of swapping a unidirectional for a bidirectional unit, I was surprised that the guy in question had gone to 1.8 kW with 4 x 460 watt panels.

The efixx guy has also fitted 3 inverters with his plug in system, not just the one, they have done at least 3 videos now and they seem to be saying there is really no problem, which I find surprising, as it was also them who did the test with the unidirectional RCBO and showed how fast it failed.

I have no intension of testing a good RCBO on solar panels by pressing the test button when the panel is producing solar, and I can see the problem if they had done that test in his rented home, but the way they did not even say do not test with the test button when the solar is producing, but is you want to test use a plug in tester is a bit sneaky, we have realised it is the built-in test button which is the problem at least they could point this out.

 

[JohnW2]

You can get small enclosures into which you can fit din-rail mounted RCDs.

Sure - but, as i keep on saying, the moment one starts talking about things like that I think one has moved away from what one really can sensibly call 'plug-in solar'.

As I've said, all this discussion seems to be premature and pretty inappropriate speculation about something which may become 'allowed'/'legal' at some point in the future.

Personally, I find it fairly hard to believe that, in the UK, we will ever be 'allowed' to buy and use PV kit which comes with a fitted BS1363 plug unless 'they' feel that it would be acceptable (and relatively 'safe') for it to be plugged into any existing BS1363 socket ... and if they don't allow that, then I don't think that anything else they may come to 'allow' (e.g. involving 'specially-installed' sockets which were not BS1363 compatible) would correspond with what people seem to be currently imagining 'plug-in solar' will be.

 

[JohnW2]

The efixx guy has also fitted 3 inverters with his plug in system, not just the one, they have done at least 3 videos now .... and they seem to be saying there is really no problem, which I find surprising ...

As I've just repeated, I do think that this discussion is very premature, but it certainly is possible that any perceived theoretical 'dangers' may actually be so small as to be of minimal cause for concern, despite ....

.... , as it was also them who did the test with the unidirectional RCBO and showed how fast it failed.

Both you and I were very surprised by how quickly their bang and smoke appeared, so I'm a little sceptical. If we assume that RCCBs born many years ago were probably 'unidirectional',then countless of those have been in service for very long periods without us having heard of any problems. In fact, looking around here, my three up-front Type S RCCBs have(for convenience) been installed 'upside down'(supply at bottom) from how they would usually be installed in a CU but, despite the fact that their test buttons have all been pressed regularly for many years, I've yet to experience any bangs or smoke ...