Schneider board main switch TP-N and 4-pole

mak · Aug 10, 2020

What's the difference between the two, one isolates N the other does not, got me confused when I was testing continuity between E-N, then I realized N was not isolated.

davesparks · Aug 10, 2020

The difference is one breaks the N the other doesn't.

What exactly do you want to know?

mak · Aug 11, 2020

davesparks said:
The difference is one breaks the N the other doesn't.

What exactly do you want to know?

Oh I thought there was a reason for the difference.

davesparks · Aug 11, 2020

mak said:
Oh I thought there was a reason for the difference.

Yes there are reasons for the difference.

Are you trying to ask why you would install one or the other?

mak · Aug 11, 2020

davesparks said:
Are you trying to ask why you would install one or the other?

Yes I'm trying to ask exactly that.

Lister1987 · Aug 12, 2020

mak said:
Yes I'm trying to ask exactly that.

There will be occasions where it is not desirable to break the neutral conductor along with the 3 line phases as doing so will present a more dangerous situation.

Have a read of Regulation 9 of EAWR .

mak · Aug 13, 2020

Lister1987 said:
There will be occasions where it is not desirable to break the neutral conductor along with the 3 line phases as doing so will present a more dangerous situation.

Have a read of Regulation 9 of EAWR .

Thanks I'll have a look into it.

davesparks · Aug 13, 2020

Lister1987 said:
There will be occasions where it is not desirable to break the neutral conductor along with the 3 line phases as doing so will present a more dangerous situation.

Which situations are those?

How does breaking the neutral conductor along with the 3 phases present a more dangerous situation?
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mak said:
Yes I'm trying to ask exactly that.

Ok

The regulations dont require isolators to break the neutral conductor if it is reliably and permanently connected to earth, so in practice you normally don't need to break the neutral where you have a TN supply.

James · Aug 13, 2020

The only issue I can see is if on a linked switch, the neutral were to break slightly before the phases, this can lead to 400v across a single phase load on the circuit for a short period of time.