Difference between 1p+N and double pole RCD

[HappyHippyDad]

I need to replace a Hagar RCD (model number CN284U). This is a type AC RCD and I wish to replace it with a type A.

The model number for the Type A equivalent is CNA584U.

They are both 100mA, 100A, S type.

The only difference being is that the Type A RCD is referred to as 1P + N rather than double pole. I'm getting a bit confused by the difference?
I thought the +N meant that the N is just switched off when there is a fault but doesn't actually detect the fault itself.

What is the difference between a double pole RCD and a 1P + N RCD? With both types of RCD the phase and neutral become open if a fault is detected, so it must relate to where the fault is detected (i.e phase or neutral). Or.. it is just different terminology meaning the same thing?

 

[Risteard]

I need to replace a Hagar RCD (model number CN284U). This is a type AC RCD and I wish to replace it with a type A.

The model number for the Type A equivalent is CNA584U.

They are both 100mA, 100A, S type.

The only difference being is that the Type A RCD is referred to as 1P + N rather than double pole. I'm getting a bit confused by the difference?
I thought the +N meant that the N is just switched off when there is a fault but doesn't actually detect the fault itself.

What is the difference between a double pole RCD and a 1P + N RCD? With both types of RCD the phase and neutral become open if a fault is detected, so it must relate to where the fault is detected (i.e phase or neutral). Or.. it is just different terminology meaning the same thing?

Not really relevant with an RCCB. If it were an RCBO then it would lack overcurrent protection in the neutral pole, but an RCCB doesn't provide overcurrent protection anyway.

 

[HappyHippyDad]

Not really relevant with an RCCB. If it were an RCBO then it would lack overcurrent protection in the neutral pole, but an RCCB doesn't provide overcurrent protection anyway.

So it's just a difference in terminology and not in any actual characteristics of the device?

 

[brianmoooore]

I'd argue that DP RCD is incorrect. A 2 channel RCD compares the current in one channel with that in the other, and to be meaningful, that means comparing the live current with the neutral current.
A DP device is what I use with my split phase supplies that are common where I live. If I used a DP RCD to supply 460V equipment, that would work fine unless the equipment had a neutral connection as well, when the RCD would trip every time more current was drawn on one phase than the other. I would have to use a DP and N RCD, so, by extrapolation, a RCD for single phase supplies is 1P + N.

 

[pc1966]

I would have to use a DP and N RCD, so, by extrapolation, a RCD for single phase supplies is 1P + N.

Do you normally use a 4P RCD and just leave one pole unused?

 

[davesparks]

What is the difference between a double pole RCD and a 1P + N RCD?

Nothing, it's two different ways of describing the same thing. 1P+N I think would be technically correct, in the same way you'd describe a 3 phase one as 3P+N, and DP is just a commonly used term.

 

[brianmoooore]

Yes, 4P, taking note to use the poles that connect to the test switch.

 

[HappyHippyDad]

Nothing, it's two different ways of describing the same thing. 1P+N I think would be technically correct, in the same way you'd describe a 3 phase one as 3P+N, and DP is just a commonly used term.

Thanks, that's a good way of explaining it and makes it clear.

 

[Lucien Nunes]

I agree that for a plain RCD, the terms should be synonymous. With an RCBO I would expect to find a 1P+N device monitoring the current in the line pole only, just as with a 1PSN MCB. A DP device would monitor the current in both poles as required on systems where neither live conductor is a neutral, e.g. 55-0-55V CT-E supplies.

 

[timhoward]

I'm waking up an older thread. Silly question:
If I want a 1 module domestic Hager RCBO that switches the Neutral, does one actually exist as everything I can find at CEF and TLC has a diagram on the side showing an unswitched Neutral.

(and I don't want an AFDD!)

 

[Risteard]

I'm waking up an older thread. Silly question:
If I want a 1 module domestic Hager RCBO that switches the Neutral, does one actually exist as everything I can find at CEF and TLC has a diagram on the side showing an unswitched Neutral.

(and I don't want an AFDD!)

Not aware of a single module one.

 

[SparkySy]

Yes they are available (Hager) I have had a quote for one from CEF a couple of days ago £125.00 +Vat single module 2pole.
Sy

 

[nicebutdim]

Yes they are available (Hager) I have had a quote for one from CEF a couple of days ago £125.00 +Vat single module 2pole.
Sy

At that price, I'd be expecting free arc fault detection

 

[SparkySy]

So would I, I nearly fell over when the quote came back!

 

[Risteard]

Yes they are available (Hager) I have had a quote for one from CEF a couple of days ago £125.00 +Vat single module 2pole.
Sy

Do you have a product code for it?