Single Pole RCBO in TT with Time Delay RCD Incomer

[D Skelton]

Back to front Damien, upstream nearer the source ;-)

Whichever way, it's subjective lol.

The point made is still the same

 

[Simlec]

I see what your saying, I just thought you had read it wrong...
upstream to me has always ment to the origin... But that could just be me

 

[D Skelton]

I see what your saying, I just thought you had read it wrong...
upstream to me has always ment to the origin... But that could just be me

No lol, I didn't read it wrong, as you say, my definition of upstream/downstream is clearly different. I've edited my post to remove doubt.

 

[spark 68]

Okay, semantics aside, assuming a DP S-Type RCD up-front ;-), why is a SPSN RCBO not suitable closer to the load in single Phase situations ?

 

[D Skelton]

It is. I put a full stop in the wrong place.

 

[telectrix]

i always refer to downstream to be the load end. current flows from source to load, same as a river flows from source, so up is the supply end, and down is the load end.

 

[yellowvanman]

Okay, semantics aside, assuming a DP S-Type RCD up-front ;-), why is a SPSN RCBO not suitable closer to the load in single Phase situations ?

In the event of a neutral to earth fault the single pole RCBO will trip but not clear the fault and so the DP RCD will trip.

Whilst not breaking any regs it messes up any discrimination you may want!

 

[D Skelton]

In the event of a neutral to earth fault the single pole RCBO will trip but not clear the fault and so the DP RCD will trip.

Whilst not breaking any regs it messes up any discrimination you may want!

SP and SPSN are different. Your statement applies to SP RCBOs, he was talking about SPSN RCBOs.

 

[spark 68]

In the event of a neutral to earth fault the single pole RCBO will trip but not clear the fault and so the DP RCD will trip.

Whilst not breaking any regs it messes up any discrimination you may want!

SPSN = Single Pole Switched Neutral in this context, I am aware SPSN could apply to single pole SOLID Neutral types too though

 

[davesparks]

SPSN = Single Pole Switched Neutral in this context, I am aware SPSN could apply to single pole SOLID Neutral types too though

No, the nomenclature is pretty well defined.

SP (or SP+N) single pole (solid neutral)
SPSN single pole switched neutral
DP double pole
TP triple pole
TPN (or TP+N ) triple pole solid neutral
TPSN triple pole switched neutral