How big should a consumer unit be? 

As big as is needed....

I sometimes think French electrons are bigger than ours. And different rules about the height of the switches and mixing things in one enclosure. nice to see  a C16 on the  lights though - no tripping when the bulb fails. Still keeps it all together.

Mike.

I sometimes think French electrons are bigger than ours. And different rules about the height of the switches and mixing things in one enclosure. nice to see  a C16 on the  lights though - no tripping when the bulb fails. Still keeps it all together.

Mike.

Another thing I have noticed in euro-boxes is that they don't mind at all if different brands of devices are mixed in the same board. I was looking at a Norwegian video where a 3 phase Hager board was filled with Hager main switches/fuseholders and RCDs but the mcbs were all ABB items.

It seems the 'Thou shalt not mix brands' mantra doesn't apply in many parts of the continent. Must be a unique British protectionist hang-up which has become overly gold-plated as a supposed standard..

Actually mapj1 , something you may be able to help with (and sorry for taking this off topic!) Our main RCD (on the right of the image) will trip intermittently and we can't quite work out why. It will do it if we have too many things with a heating element on it such as if we have the water heater on and then switch on the kettle. Or if we have the Infrared heating panel on and then switch on the oven. There's no one thing that will do it although I did put on the kettle by itself once and that was enough to trip it. However, the kettle isn't a common factor as to when it trips. It just seems to be the catalyst to tip it over the edge. It's a 45 amp so should be enough to handle everything but it does trip annoyingly at really inconvenient moments! 

I wonder if it's just a faulty main RCD or if there's something else going on? What would you suggest?

well arguably it may be justified to worry about 3rd party  MCBs on supplies where the PSSC is > the breaker 6kA rating and we are relying on the annex ZA and discrimination with the company fuse,  but it is very hard to justify it for any item downstream of an MCB.

In my experience (German, mostly) the continentals are much more used to seeing time switches, contactors, bell transformers, indeed almost anything DIN mounting,  in the cabinet that is rather more complex than the UK idea of a consumer unit - indeed if you wanted to put such things in a UK consumer unit you would struggle to find a maker that did all the options you might like. This may mean that only MCBs are on buss, and there are a few loops of wire to other devices, but done well this is not an issue. It is also common to put a socket in there for test meter or clip lamp, so a quick voltages and Zs test does  not need any covers off.

I must say it is an approach that has some appeal.

Mike.

You need to know how close it is to tripping before it does. In the UK with exposed meter tails a sensitve current meter clamped around both tails to read only the difference can help reveal what is going on. 

Understand that the 45 A figure is the load current, but that is only part of the battle - the trip looks at the difference between L and N current, and when this exceeds the threshold (30mA for safety of life on 240V systems, but maybe 100mA or 300mA if there are more sensitive ones downstream). Basically if electrons go down one wire and a different number come back up the other, then the assumption is that some got off part way round and there is a fault, that worst case may involve a person between L and earth, and that should trip an automatic disconnection. In the UK you would only have use a single 30mA device for a small flat or a limited no of circuits, it would be more usual to divide the load up across more than one RCD or to have an RCBO per final circuit, as the more stuff you plug in, each with a natural leakage to earth of a mA or two the more likely is a no fault trip - the sort of thing you describe.
So firstly what other numbers are on that RCD, and are there others ? Then, how easy is it to get in and measure things?

Mike.

From what I gathered from the video, the Norwegian electrician said that they didn't have to do much by the way of live testing - just continuity and insulation resistance for new circuits. The live side - Ze - was down to the electricity supplier, although he did check RCD trip times.

Get a man in. (Smiley). The RCD is probably doing what it was designed for. There are procedural steps to be taken in the fault finding using test instruments.

Jaymack

If it helps I managed to extract this from Lisa's original picture:

Looks to me like a 500mA with a 45A load trip setting. Doesn't help with the settings on the upstream unit of course...

   - Andy.