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[hope this isn't off topic for this board]

I'm doing a DIY electric board for my terrarium: in case something goes wrong at least the whole electric circuit won't switch off.

My current setup is a C10 breaker followed by a main on/off switch, and then an on/off switch for every power outlet. All switches have a light to show if it's on or off.

Red is "phase", Black is "phase" returning from switch, Blue neutral and green/yellow is earth. The light for switches have a black cable. (*) These are the French standards, and the board will be plugged in a French power outlet (230V AC, 50 Hz).

Question: I think that a C10 breaker is too much. I'm thinking of putting either a C6 or a C2 breaker. From where to where do I mesure the current total instensity when all appliances are on?

enter image description here

(*) Sorry for my lack of lingo, but google translate didn't help much.

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You might want to mention where you are - electrical standards and practices vary quite a bit world wide, so knowledge of the locality may be necessary. – Michael Kohne Oct 7 '13 at 0:47
@MichaelKohne BlakBat's profile says France, but the work could be anywhere. – bib Oct 7 '13 at 12:31
You should be able to estimate the load (which is the way overcurrent protection is usually selected), using the labeling on the devices you'll be connecting. Current (I) = wattage (power)(p) / voltage (V), though some devices might have current ratings listed directly. This will give you the current for each device. Since it looks to be a parallel circuit, total current (It) = I1 + I2 + I3... – Tester101 Oct 7 '13 at 13:47
@MichaelKohne: good remark. bib: good deduction. I'll edit the question to specify that this is done for a french circuit board. – BlakBat Oct 7 '13 at 17:04
@tester101: I have a wattmeter that I just plugged in before the main switch. It currently reads 70W. So 70 / 230 (estimate, not measured) = 0,30A. That means that a C2 breaker should be more than sufficient if my calculations are correct? right? – BlakBat Oct 7 '13 at 17:08

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