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Single Pole or 1P + N circuit breakers

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Monkeh:

--- Quote from: soldar on March 27, 2019, 09:06:30 pm ---
--- Quote from: Benta on March 27, 2019, 08:34:28 pm --- Fusing neutral is nonsense.
--- End quote ---

In Spain it is required by the regulations and there are several good reasons. One is that some places are supplied 230 V with two phases from a 127/230 volt system and there you, obviously, need to cut both wires just like in America you need to cut both wires in a 220 V circuit.
--- End quote ---

That's not fusing the neutral, because it isn't a neutral.

soldar:
In Spain the electric code requires cutting all conductors, always, including neutral, always. always.

I thought I had made that clear in my earlier post.

Relevant regulation is Reglamento de Baja Tensión ITC-BT-17. It mandates (1) General shutoff switch which must cut all wires, (2) General GFCI which must protect all circuits and cut all wires, (3) individual circuit breakers which must cut all wires.

Monkeh:

--- Quote from: soldar on March 27, 2019, 09:45:21 pm ---In Spain the electric code requires cutting all conductors, always, including neutral, always. always.

I thought I had made that clear in my earlier post.

Relevant regulation is Reglamento de Baja Tensión ITC-BT-17. It mandates (1) General shutoff switch which must cut all wires, (2) General GFCI which must protect all circuits and cut all wires, (3) individual circuit breakers which must cut all wires.

--- End quote ---

I didn't claim otherwise. I simply made the point that if you have two active conductors you don't have a neutral.

I've yet to see any of the good reasons for requiring a breaker to interrupt neutral.

soldar:
Two scenarios I can think of.

(1) If the neutral wire breaks then the neutral wire can be brought to live voltage through devices plugged in.

(2) If a 220/380 distribution transformer fails and temporary emergency supply needs to be provided it can be done with a 127/230 transformer or 127/230 mobile generator using two live phases. 

I am sure there are others.

I am not saying it is a must do. Every technical decision has its pros and cons. Cutting both conductors is, obviously, safer. OTOH there is added cost and complexity.

As I said, In my apartment I only cut the live wires because I like it that way but it does not meet code regulations.

Note also that in Spain earth and neutral are not connected as they are in America. Another case of doing things differently.

Monkeh:

--- Quote from: soldar on March 27, 2019, 11:09:57 pm ---Two scenarios I can think of.

(1) If the neutral wire breaks then the neutral wire can be brought to live voltage through devices plugged in.
--- End quote ---

If the neutral wire upstream breaks, how many additional faults are required for danger to be present?


--- Quote ---(2) If a 220/380 distribution transformer fails and temporary emergency supply needs to be provided it can be done with a 127/230 transformer or 127/230 mobile generator using two live phases.
--- End quote ---

That is a very country specific situation involving attempting to connect two incompatible systems, and requiring the use of a two-pole breaker universally is a lazy fix at best.


--- Quote ---Note also that in Spain earth and neutral are not connected as they are in America. Another case of doing things differently.

--- End quote ---

If earth and neutral are not connected then by definition there is no neutral. Note that I'm not American, also..

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