Renew old distribution: Separate terrace from living room?

Hi guys,

in the course of the renovation, I am unsure about how my terrace connection should look. In advance: An electrician has been commissioned to renew the meter cabinet and, if necessary, also connect some newly drawn lines and advise me (or will coordinate in the next few weeks).

Nevertheless, I am somewhat interested in getting everyday experience.

Currently, the terrace is protected via the living room; this is to be separated. I have a main switch in the living room that can completely switch off outside. Then there are 3 switches outside for 4 lamps and an outlet, which are quite poorly installed flush-mounted outside in the brickwork.

I have broken my SweetHome3D, so now using PowerPoint... :D I hope it becomes clear.


I now want one switch for 4 lamps as well as possibly an outlet. The whole thing should be separated from the living room. The electrician has already offered/suggested an RCD/LS each for the garden shed and garage.

Now the question... What does it look like in everyday life? Do you really need a switch for the lighting from inside, or is it enough to have it outside? Do outlets have to/should be able to be switched off from inside as well?

I can very well imagine arranging the supply via the garden shed, and instead of flush-mounted, using surface-mounted switches.
- One light switch outside on the terrace
- One light switch inside the living room, both switches combined with a Shelly, so that a two-way switch is practically realized and all 4 lamps are switched
- Outlets get permanent power from the garden shed (--> also planned to be switchable, possibly from the garden shed? It can theoretically be locked).


Opinions, ideas, everyday experiences? So far we live on the 2nd floor without such toys :D

Now the question... What does it look like in everyday life? Do you really need a switch for the lighting from the inside, or is it enough to have it on the outside? Should/must sockets also really be switchable from the inside?

Necessary is the wrong word. Somehow turning on and off, but whether that happens with a switch inside or outside or only via motion sensor or completely differently, doesn't matter.

The necessity rather depends on what suits you best, and that depends on your situation. For example, how well can the neighbor (during your vacation, longer absences) "use" your sockets? Then you probably want them to be switchable from the inside (who really thinks about always turning off the circuit breakers appropriately for vacation?). With the lighting, I know the question more the other way around – "do I really need a switch outside, inside is enough and is secure against unauthorized operation."

And if you're already laying new cables, why work with Shelly then? Lay a cable from outside to inside and build a proper circuit, instead of a makeshift solution like with a Shelly?

Regarding sockets: Based on my experience, I would say rather not make them switchable! Because the problem is that the usual switches are only designed for 10A and therefore can only be protected accordingly. This means that a garden shredder already reaches or exceeds the fuse limit. Higher continuous load switches are rare and therefore come with pharmacist prices. Therefore, better to omit them; an additional switching device should suffice.

Regarding sockets: Based on my experience, I would say rather not make them switchable!

The outdoor sockets on the house have been designed to be switchable. In case we need high energy consumers outside, there is a 32A CEE socket switched in the fuse box – wired with generous cross-section and properly secured. This way, neither a shredder nor a wood splitter is a problem without having to use a combustion engine or have a cable lying around on a terrace. My tip: One fuse per terrace, garden power wired separately again.

Why integrate Shellys? To run automations, to possibly integrate PMs and BMs, to switch the light remotely as you like. Although this, of course, goes against classical switching technology. Philips has a usable retrofit with its Hue, showing how to keep lamps permanently powered without losing the functionality of the switches; whether this is also the case with Shelly... I assume so...

In outdoor areas, it definitely makes sense to consider once what should function independently or even must function independently under certain circumstances. If I protect the entire outdoor system with a single RCD, the lights, fountain, outdoor socket(s), sauna, jacuzzi, cistern pump no longer work because there is a ground fault in one of the circuits. So at least I protect the lights and especially the outdoor socket separately. There is now a device combining RCD + B16 in the width of a standard circuit breaker.

In my own sub-distribution, I protect every outdoor circuit individually with RCD + Bxx. This way, one also has the (possibly enormous) advantage of immediately knowing which circuit caused the RCD to trip.

Switching outdoor sockets via a light switch, as Tolentino mentioned... that not only makes no sense because you are limited to 10A, but because an RCD is behind it in the sub-distribution. This is mandatory for outdoor installations. And as a rule, the electrician does not protect the outdoor socket with its own RCD; other things are also connected there, in the worst case heating, refrigerator, and ventilation system...

What is so bad about this... anyone who in electrician training once cut through a 3-phase cable by mistake and was almost lynched afterward by angry office workers knows why. In a normal network, the neutral is never completely without current. This is only the case in ideal electric motors or three-phase heaters. A short circuit alone between N and PE is enough, and a 30mA RCD trips... almost always.

Now if a prankster plugs not a Schuko plug for his beatbox but a bridge between N and PE into your outdoor socket... usually, L is on the left and N on the right, nearly all electricians do it that way... Then you come back after 3 weeks of vacation to a freezing cold apartment with a moldy fridge. Because the RCD has tripped due to asymmetries between the phases and thus an imbalance current between L(1-3) and N... and a fault current between N and PE.

The joke is... this also works if the circuit breaker (the MC) is switched off. The neutral still runs through the higher-level RCD, which usually protects a whole group of MC breakers.

That is why a switchable outdoor socket is always(!!) designed all-pole switched, via a suitable switch, usually in the sub-distribution.

And a CEE socket should definitely be considered, if economically feasible. Electric always replaces combustion engines more and more, but in this comparison, 3.6kW power is unfortunately rather at the lower end. So if you are already going to it, you should consider whether not to install a three-phase socket, CEE, outdoors. Whether 16A or 32A... 16A three-phase is 11kW... 32A accordingly 22kW. An electrical garden appliance with 22kW that one needs in a normal single-family house, I would like to see that...

The electrician probably had a lot of sales talent, because you do not need the "generous cross-section" either. There are current capacity tables according to tabular books, and they apply. You gain absolutely nothing by choosing one or more cross-sections larger, except that the electrician makes more money because he sometimes buys it cheaper and charges much more...