Solar ... In the news

QrizB

Here's an article about Germany and their million-or-so plug-in balcony solar PV systems:

https://happyeconews.com/german-balcony-solar-balconkraftwerke/

Typically these systems are self-installed and cost under £500 for an 800-watt nominal output.

The article notes:

The United Kingdom currently prohibits plug-in solar systems due to concerns about building safety regulations and aesthetics, though authorities may review these restrictions soon.

I think the UK currently has about 2 million solar PV installations, roughly one home in twelve. Looking at the colours on the PVGIS map it seems that Germany is slightly better suited for solar PV than the UK is, but even so I suspect there would be a reasonable demand for these if the relevant regulations were relaxed.

Martyn1981

Hi QrizB. Earlier this year Wifey showed me a pic of BiL's balcony in Sweden. He and the Mrs, had just installed a couple of those woven wood type wind breaks. One on one end, and one along half the front, to reduce the wind coming from that direction. I mentioned balcony / plug-n-play PV, but they'd never heard of it. And he's a bit of a tech geek, and electrical engineer. The potential for this market is huge.

Fingers crossed the UK adopts something akin to the German 800W rule soon, to allow these small systems. For ~£2k, you can already get about 2kWp of PV panels and 6kWh of bidirectional battery storage with an 800W limit on the grid side AC output. Plus they have AC side sockets capable of greater output to power specific devices. Not a bad package if you can DIY the panel install near the batteries.

Qyburn

How are the socket circuits in Gernany wired, how many typically on a circuit and what size breaker?  Asking because the only reason we're allowed to have multiple sockets on a ring or radial, is because the British plugs are fused. That was the innovation in 1947 (ish), prior to that each power point had its own fuse at the fuseboard.

QrizB

Qyburn said:

How are the socket circuits in Gernany wired, how many typically on a circuit and what size breaker? 

A very quick Google suggests that general purpose residential circuits (as opposed to cookers, showers etc.) are 1.5mm2 radial circuits with 16A breakers. No specific limit on the number of sockets per circuit, circuits can also serve lighting.

Qyburn said:

Asking because the only reason we're allowed to have multiple sockets on a ring or radial, is because the British plugs are fused.

Not sure the theory really backs that up. The fuse in the plug protects the appliance flex, not the circuit.

Qyburn

QrizB said:

Not sure the theory really backs that up. The fuse in the plug protects the appliance flex, not the circuit.

That's correct, the last bit. The plug top fuse protects the appliance flex, limiting it to a nominal 13A. The final circuit itself is protected by the overcurrent device in the distribution board, which might be 32A for a ring final. 

If you didn't have the plug top fuse, the appliance flex would also need to be good for nominal 32A. 

JKenH

QrizB said:

Qyburn said:

Asking because the only reason we're allowed to have multiple sockets on a ring or radial, is because the British plugs are fused.

Not sure the theory really backs that up. The fuse in the plug protects the appliance flex, not the circuit.

It’s a shame it doesn’t protect the plug as well, as many people with granny chargers have found out. Even with a 2kW convector heater, nominally 8A, the plug can get very hot. 

michaels

QrizB said:

Qyburn said:

How are the socket circuits in Gernany wired, how many typically on a circuit and what size breaker? 

A very quick Google suggests that general purpose residential circuits (as opposed to cookers, showers etc.) are 1.5mm2 radial circuits with 16A breakers. No specific limit on the number of sockets per circuit, circuits can also serve lighting.

Qyburn said:

Asking because the only reason we're allowed to have multiple sockets on a ring or radial, is because the British plugs are fused.

Not sure the theory really backs that up. The fuse in the plug protects the appliance flex, not the circuit.

Interesting. I thought the standard for plug rings was 2.5 with 1.5 only for lighting?

QrizB

michaels said:

QrizB said:

Qyburn said:

How are the socket circuits in Gernany wired, how many typically on a circuit and what size breaker? 

A very quick Google suggests that general purpose residential circuits (as opposed to cookers, showers etc.) are 1.5mm2 radial circuits with 16A breakers. No specific limit on the number of sockets per circuit, circuits can also serve lighting.

Interesting. I thought the standard for plug rings was 2.5 with 1.5 only for lighting?

In Germany? I don't think ring circuits are common over there?

IIRC the UK adopted ring circuits to save money on copper after WWII.

Qyburn

michaels said:

QrizB said:

A very quick Google suggests that general purpose residential circuits (as opposed to cookers, showers etc.) are 1.5mm2 radial circuits with 16A breakers. No specific limit on the number of sockets per circuit, circuits can also serve lighting.

Interesting. I thought the standard for plug rings was 2.5 with 1.5 only for lighting?

Over here a 16A radial or 32A ring would use 2.5sq.mm for L and N, 1.5sq.mm E (CPC). 

Relevance to this discussion is that the cable would need to be rated for 16A plus the maximim current from the "balcony" inverter. I don't know whether there are other reason for the UK not permitting microgeneration on the same final circuit as loads. That's the reason that stands out, they don't want current that doesn't pass through the protective device.