Maybe you're right. I've never seen single module wide double pole breakers. I also can't understand why they would have RCDs like that and then a bunch of MCBs.
Yeah, seems pretty wild to go to all the effort with the AN busbar and not have individual RCBO's, makes fault finding so much easier and limits nuisance tripping
The equipment in France is different from what you have. This is for commercial buildings (between residential and industrial, to put it simply). What you see here is a distribution board powered by 400V AC three-phase power. I've balanced the loads per phase across the four rows of the board.
Each row starts with a 30mA residual current device (RCD) rated at 63A, followed by branch circuit breakers of varying ratings (10A, 16A, 20A, 32A) depending on the downstream load. The top busbar supplies power to that row.
Feel free to ask me any further questions and let me know if my explanation is unclear.
Why the double pole MCBs? Is it a regulation thing in France, or just the convenience of being able to put MCBs and RCBOs on the same busbar if some circuits don’t require RCD protection?
I’ve always found it quite interesting how most western 230V countries have very similar equipment available, but quite different regulations and standard practices for how it’s used
Most non-industrial equipment operates on 230V, hence the use of a double-pole circuit breaker. The residual current device (RCD) at the head of each circuit is there to protect people from insulation faults; therefore, it is mandatory in our system to protect all the circuit breakers in the panel, regardless of their rating.
Why not use a single RCD for all the circuit breakers? Because the regulations in our system require one RCD for a maximum of eight circuit breakers.
It sometimes happens that residential or commercial electrical panels are supplied with 400V (3 phases + 1 neutral), hence the need to balance each of the phases.
The advantage of a double-pole circuit breaker is that in the event of a power outage, it interrupts both the neutral and the live wire. A single-pole circuit breaker, on the other hand, would only interrupt the live wire, which means there could be a risk of leakage current in the neutral.
Another advantage of double-pole circuit breakers is that they don't require mixing the neutral wires, which is crucial for preventing tripping of residual current devices (RCDs).
My question is why not use RCBOs thus reducing nuisance tripping as well as reducing what circuits/equipment get affected by a fault.
Also why do you think the voltage matters in relation to needing double pole breakers? Most/many countries that I am aware of that run on 230/400v don't require it.
Good points Schrojo18!
Here is the context for the French standards (NF C 15-100):
1. Regarding RCBOs:
You are absolutely right that RCBOs are technically superior to avoid nuisance tripping. However, in the French residential market, RCBOs are significantly more expensive (often 8 to 10 times the price of a standard MCB).
For a full panel, this represents a huge cost increase for the client. We usually follow the '1 RCD for 8 MCBs' rule to balance safety and budget, reserving RCBOs for critical circuits like freezers or alarms.
2. Regarding Double Pole (1P+N) breakers:
It’s less about the 230V itself and more about our TT earthing system. In France, a Neutral-to-Earth fault will trip the RCD. If you only switch the phase, you cannot isolate the fault to reset the rest of the panel without manually disconnecting the neutral wire from the busbar.
By using 1P+N breakers, we can isolate both conductors instantly. It makes troubleshooting a breeze: if a circuit has a neutral fault, you just flip the breaker down, and the rest of the house gets power back immediately.
It’s a different philosophy, but very efficient for maintenance!
In Australia we are restricted to 3 MCBs per RCD in domestic and in commercial/industrial we are required to minimise nuisance tripping. For us it would be very unlikely for us to put thatany MCBs on a single RCD even though an MCB costs $5-10 and an RCBO costs $30. The value in the segmentation is greater to us than the extra costs.
Also in regards to your other point, individual RCBOs would be of benefit here too.
It's mostly due to budget or space constraints, 1 module wide electromechanical RCDs (electronic RCDs aren't always allowed, it depends on the country) only exist in a couple of sizes and are far more expensive than an MCB.
I was referring to 1 mod wide RCBOs which are more expensive but also are available in all regular flavours from 2 or 6A up to 40 or 63A even in 3 mod wide 4 pole 400v ones.
The only difference between domestic and commercial circuit breakers is primarily the short-circuit current breaking capacity: 3000A for domestic vs 6000A for commercial.
Looks good, but why do you have RCDs feeding RCBOs?
Are they RCBO's? I can't see a test button on them, I'm familiar with the Max9 gear, but have never seen a double pole breaker like that
Maybe you're right. I've never seen single module wide double pole breakers. I also can't understand why they would have RCDs like that and then a bunch of MCBs.
Yeah, seems pretty wild to go to all the effort with the AN busbar and not have individual RCBO's, makes fault finding so much easier and limits nuisance tripping
The equipment in France is different from what you have. This is for commercial buildings (between residential and industrial, to put it simply). What you see here is a distribution board powered by 400V AC three-phase power. I've balanced the loads per phase across the four rows of the board.
Each row starts with a 30mA residual current device (RCD) rated at 63A, followed by branch circuit breakers of varying ratings (10A, 16A, 20A, 32A) depending on the downstream load. The top busbar supplies power to that row.
Feel free to ask me any further questions and let me know if my explanation is unclear.
Why the double pole MCBs? Is it a regulation thing in France, or just the convenience of being able to put MCBs and RCBOs on the same busbar if some circuits don’t require RCD protection?
I’ve always found it quite interesting how most western 230V countries have very similar equipment available, but quite different regulations and standard practices for how it’s used
Most non-industrial equipment operates on 230V, hence the use of a double-pole circuit breaker. The residual current device (RCD) at the head of each circuit is there to protect people from insulation faults; therefore, it is mandatory in our system to protect all the circuit breakers in the panel, regardless of their rating.
Why not use a single RCD for all the circuit breakers? Because the regulations in our system require one RCD for a maximum of eight circuit breakers.
It sometimes happens that residential or commercial electrical panels are supplied with 400V (3 phases + 1 neutral), hence the need to balance each of the phases.
What is the advantage of using double pole breakers for branch circuits instead of single pole?
The advantage of a double-pole circuit breaker is that in the event of a power outage, it interrupts both the neutral and the live wire. A single-pole circuit breaker, on the other hand, would only interrupt the live wire, which means there could be a risk of leakage current in the neutral.
Another advantage of double-pole circuit breakers is that they don't require mixing the neutral wires, which is crucial for preventing tripping of residual current devices (RCDs).
Maybe you should make sure your earthing is correct if you are worried about neutral voltages.
My question is why not use RCBOs thus reducing nuisance tripping as well as reducing what circuits/equipment get affected by a fault. Also why do you think the voltage matters in relation to needing double pole breakers? Most/many countries that I am aware of that run on 230/400v don't require it.
Good points Schrojo18! Here is the context for the French standards (NF C 15-100):
1. Regarding RCBOs:
You are absolutely right that RCBOs are technically superior to avoid nuisance tripping. However, in the French residential market, RCBOs are significantly more expensive (often 8 to 10 times the price of a standard MCB).
For a full panel, this represents a huge cost increase for the client. We usually follow the '1 RCD for 8 MCBs' rule to balance safety and budget, reserving RCBOs for critical circuits like freezers or alarms.
2. Regarding Double Pole (1P+N) breakers:
It’s less about the 230V itself and more about our TT earthing system. In France, a Neutral-to-Earth fault will trip the RCD. If you only switch the phase, you cannot isolate the fault to reset the rest of the panel without manually disconnecting the neutral wire from the busbar.
By using 1P+N breakers, we can isolate both conductors instantly. It makes troubleshooting a breeze: if a circuit has a neutral fault, you just flip the breaker down, and the rest of the house gets power back immediately.
It’s a different philosophy, but very efficient for maintenance!
In Australia we are restricted to 3 MCBs per RCD in domestic and in commercial/industrial we are required to minimise nuisance tripping. For us it would be very unlikely for us to put thatany MCBs on a single RCD even though an MCB costs $5-10 and an RCBO costs $30. The value in the segmentation is greater to us than the extra costs.
Also in regards to your other point, individual RCBOs would be of benefit here too.
It's mostly due to budget or space constraints, 1 module wide electromechanical RCDs (electronic RCDs aren't always allowed, it depends on the country) only exist in a couple of sizes and are far more expensive than an MCB.
I was referring to 1 mod wide RCBOs which are more expensive but also are available in all regular flavours from 2 or 6A up to 40 or 63A even in 3 mod wide 4 pole 400v ones.
In case anything starts tripping the RCD, having two pole MCBs allow for easier troubleshooting.
A dead short between neutral and earth will trip most RCDs, so we need to open both poles.
Interesting you mention this as a commercial building but are using a domesting series of breakers
The only difference between domestic and commercial circuit breakers is primarily the short-circuit current breaking capacity: 3000A for domestic vs 6000A for commercial.
In Australia you can't really get anything bellow 6ka anymore though there are some 4.5ka still
These aren't RCBOs, they're regular circuit breakers that also disconnect neutral to fully isolate circuits.
looks like a hotel or a school
It's a physiotherapist's office
Wait... if you move the ground bus to the top, won't the extra volts fall out of the bottom?
Is this humor?
That was my hope 😟
I'm always wary of machine translation, but it was very enjoyable to read 😁
It even has an EXTINCTION button.
Thank you for your service.
Why does it seem like this style of breaker boxes is so much cleaner looking in general than the ones I see here in the states?