Difference between "Single pole with switched neutral" AND "Double Pole" ?

[michael8554]

What's the difference please between:

"Single pole with switched neutral" means a circuit breaker or switch that switches both the live (hot) and neutral wires, ensuring complete isolation of the circuit when turned off, unlike a single-pole switch that only switches the live wire."

AND

"Double Pole means a double-pole switch or circuit breaker switches both the live and neutral wires, providing complete isolation of the circuit when turned off."

 

[binky]

One is a more compact version of the other. Double pole being older larger version.

 

[nicebutdim]

SP+N lacks overcurrent protection on the neutral.

 

[poni]

Double pole is for two phases circuits and single pole +N is for single phase circuits , like Nicebutdim says

 

[michael8554]

So a "Single pole with switched neutral" Type A RCBO for an EV CU, what is the downside if any ?

 

[nicebutdim]

So a "Single pole with switched neutral" Type A RCBO for an EV CU, what is the downside if any ?

In general there is no downside with SP+N RCBOs, considering the alternative is single pole devices at the roughly same price or sometimes more. There are a number of upsides to their use.

The only time I would specifically not use one of these is if a double pole device was specifically required, either through regulation or job specification.

For your example of an EV charge point I'd need to check current regulatory requirements as this isn't the sort of work I'm often involved with.

 

[mainline]

Dp (sp+n) rcbos are helpful where you have a N+E fault as sp ones won't clear the fault, particularly on TT earthing where an upfront rcd is being used.

 

[mainline]

Double pole is for two phases circuits and single pole +N is for single phase circuits , like Nicebutdim says

Where would the Neutral conductor terminate to give isolation ?

 

[mainline]

So a "Single pole with switched neutral" Type A RCBO for an EV CU, what is the downside if any ?

722.531.3.1 RCDs shall disconnect all live conductors.

As @nicebutdim check with the manufacturer as to the requirements.

 

[poni]

sorry I don't understand the question,
I was explaining the difference between, single pole +N and double pole MCBS , also please just note that you don't need a neutral for two phase circuits,

 

[mainline]

sorry I don't understand the question,
I was explaining the difference between, single pole +N and double pole MCBS , also please just note that you don't need a neutral for two phase circuits,

@poni said: Double pole is for two phases circuits.

A DP MCB can be used on single phase and provide isolation.

A DP (Double Pole) MCB on a 2-phase supply would not provide complete isolation.


@nicebutdim correctly said that the difference is: SP+N lacks overcurrent protection on the neutral.

 

[nicebutdim]

To be fair the OP doesn't mention RCBOs, so I can see how someone might have picked up only on the double pole aspect of the post.

I might easily have answered the wrong question, too, but couldn't think of any other application for SP+N switching in circuit breakers.

 

[poni]

A DP (Double Pole) MCB on a 2-phase supply would not provide complete isolation

why not?

 

[mainline]

why not?

Typically, a 2 phase supply used a Neutral, hence you couldn't achieve complete isolation using 2 poles.

 

[poni]

Typically, a 2 phase supply used a Neutral, hence you couldn't achieve complete isolation using 2 poles.

Typically, a 2 phase supply has no neutral, (400V or 50-50V)