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

michael8554 · 2025-03-06T12:59:48+0000

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 · 2025-03-06T14:44:17+0000

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

nicebutdim · 2025-03-06T16:25:09+0000

SP+N lacks overcurrent protection on the neutral.

poni · 2025-03-06T17:08:42+0000

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

michael8554 · 2025-03-06T17:13:37+0000

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

nicebutdim · 2025-03-06T17:56:22+0000

michael8554 said:
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 · 2025-03-06T18:07:55+0000

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.