2 pole (mini) RCBOs

[benstoneham]

Does anyone know of a 2 pole (phase and neutral) 'mini' RCBO i.e. ~18mm?

I have found one made by an Aussie company :

http://www.heinemannelectric.com.au/products_select.asp?p=12
http://www.heinemannelectric.com.au/products.asp?PFID=31

but although there are a few (MK etc) single pole RBCOs in that size, I can't find anything with 2.

 

[RF Lighting]

AFAIK, all UK DP RCBOs occupy 2 standard modules.

 

[JohnD]

No, but tell us what brand of consumer unit do you wish to fit it to?

why do you need it to be both (a) 18mm and (b) DP?

p.s. the Heine you posted a link to says
"Switches both the Active and Neutral Poles
26mm Width "

 

[Lectrician]

2 pole, as in it switched the neutral too?

I am yet to come across one. They are always derived from a SP MCB, with the MCB mechanism doing the isolating when tripped (so single pole). If you ever have to fit an MEM field fit RCBO 'pod' to a standard MCB, you will appreciate how a SP RCBO is created.

RCBO's that switch double pole will always be two modules wide as far as I am aware.

 

[JohnD]

I'm told you can fit a MEM pod to a DP MCB, though I've never done it, and haven't got a Memshield catalogue to look it up.

It would then be 36mm wide anyway

 

[RF Lighting]

[pedant]SP MCBs etc are 17.5mm wide[/pedant]

 

[Lectrician]

No, the pod sits on top of an MCB, so it would remain at a two module width.

I have not come across this. I would guess it would be a single pole and switched neutral MCB, not a true DP MCB. I am 99.99% sure of this. I know you cannot fit them to TP breakers.

 

[Lectrician]

Although, here is a good (off topic) link.

http://www.memonline.com/news26.html

 

[Lectrician]

Yup - look here.

Single Pole, SWITCHED neutral.

http://www.memonline.com/f05.html

 

[JohnD]

you mean the right-hand one in the pic? I think you are right, SPSN not DP.

Like I said - 36mm wide (well maybe 35mm)

 

[RF Lighting]

Hager do a SP MCB with switched neutral in a single width module. AFAIK this doesn't extend to their RCBO range.

 

[Lectrician]

you mean the right-hand one in the pic? I think you are right, SPSN not DP.

Like I said - 36mm wide (well maybe 35mm)

Yup, sorry John - thought you meant three modules wide.

The text also stats SPSN, so, yep, Switched Neutral.

 

[benstoneham]

Right now CU could be selected as required; I was just curious as to what the options were as a per-circuit RCBO arrangement would be very flexible obviously (cost aside).

From what I have so far understood of the changes in the 17th ed requirements for RCBOs on most circuits, it seemed there could be an argument for one-per circuit, if only for convenience to prevent multiple circuits switching off if done using a split board.

By extennsion then, the need for 'mini' i.e. 18mm or so RCBOs comes because many CUs wouldn't be able to accomodate so many 35mm modules..

Anyway, when I looked up what was available, it seemed as though the Australian co was the only one available.. I just wondered why that was (perhaps the Aussies' have specific regs re RCBOs disconnecting neutrals).

 

[JohnD]

why do you need it to be DP?

 

[Lectrician]

You could RCBO protect circuits to comply to 16th/17th with a SP RCBO. It still looks for an imbalance between live/neutral and earth, but simply only opens the live conductor when there is a fault.

SP RCBO's are the most common these days - DP, or SPSN are becomming a rarety.