Can this RCD Be Fed from the bottom ?

[Filip cashman]

Can I feed this RCD from the bottom or is strictly the top feed only ?

 

[SUNRAY]

Can I feed this RCD from the bottom or is strictly the top feed only ?

No problem.

 

[Filip cashman]

No problem as in it won't damage or affect the rcd in any way?

 

[JohnW2]

No problem.

I think there is one potential problem. ... if one wires it the 'unintended' way around then if one keeps one's finger on the test button, one will rapidly burn out the resistor. Wired.conventionally, the 'test current path' disappears as soon as the device operates.

Kind Regards, John

 

[RandomGrinch]

if one wires it the 'unintended' way around then if one keeps one's finger on the test button, one will rapidly burn out the resistor.

I may be very wrong - but from the diagram, I believe the path from the test button is broken from the same mechanism that disconnects the L and N...

Although, could connecting it from the bottom cause issues with bus bars?

 

[JohnW2]

I may be very wrong - but from the diagram, I believe the path from the test button is broken from the same mechanism that disconnects the L and N...

You may well be right, and that would be sensible, but the degree of 'clarity' (or otherwise) in the 'blown-up' diagram you've posted does not enable me to be sure of that . However, even if that is true of the one we're looking at (and may even be true of them all 'these days'), I'm pretty sure that, in the past, I've seen ones which have no switching of the test current path, and are therefore presumably susceptible to the issue I mentioned.

Although, could connecting it from the bottom cause issues with bus bars?

It could, but I would suspect that, since the question is being asked, the OP is probably not talking about installing it in a conventional CU.

Kind Regards, John

 

[SFK]

I would not recommend 'changing it from the normal'.

The next person servicing it will have normality bias, not expect that change.

This will put them at an increased risk of electrocuting themselves.

SFK

 

[Sureitsoff?]

Is it being fitted in an enclosure with other modules or on its own? If solo could you mount it upside down, not convential but might make your wiring easier.

 

[SUNRAY]

On older units I've seen the test circuits have been one wire from each side of the main contacts.
The issue with that being continued operation of the button could potentially supply 'test current' to the load side.
I believe they are all made as shown now.

 

[SUNRAY]

Not all busbar are at the bottom. For example Merlin Isobar, old Hagar and vertical 3ph boards.

 

[Filip cashman]

You may well be right, and that would be sensible, but the degree of 'clarity' (or otherwise) in the 'blown-up' diagram you've posted does not enable me to be sure of that . However, even if that is true of the one we're looking at (and may even be true of them all 'these days'), I'm pretty sure that, in the past, I've seen ones which have no switching of the test current path, and are therefore presumably susceptible to the issue I mentioned.

It could, but I would suspect that, since the question is being asked, the OP is probably not talking about installing it in a conventional CU.

Kind Regards, John

It’s being installed in a older Hager board , the old GE RCD is being supplied from the breaker beside it with a little bus bar link from the non RCD side of the board

 

[mattylad]

Whilst I don't install consumer units I do build a lot of electrical panels and we have a golden rule that incoming power always goes to the top of the MCB. It may not matter for how it works electrically but if the incoming connection were to become loose there is less chance of a live wire falling out of the top, if in the bottom then we have a potentially dangerous wire flapping about in the panel and may short to other things.

Of course the rule can be broken if the design calls for it but in general its overall safer to use top entry if it's being supplied by a wire, CU's are powered from the bottom by a bus bar but this is connected at multiple points and less likely to fall out.

 

[Filip cashman]

Hmm good point but the RCD protected breakers are fed by one wire and have a sort of linkout busbur feeding them all

 

[JohnW2]

On older units I've seen the test circuits have been one wire from each side of the main contacts.
The issue with that being continued operation of the button could potentially supply 'test current' to the load side.

That's obviously the sort of issue I was referring to.

I believe they are all made as shown now.

Fair enough - I acknowledged that as a possibility when I wrote:

..... However, even if that is true of the one we're looking at (and may even be true of them all 'these days'), I'm pretty sure that, in the past, I've seen ones which have no switching of the test current path, and are therefore presumably susceptible to the issue I mentioned.

Kind Regards, John

 

[JohnW2]

Is it being fitted in an enclosure with other modules or on its own? If solo could you mount it upside down, not convential but might make your wiring easier.

It might well make the wiring easier, but it would mean that the operating lever would then be "down for on", which some people might regard as undesirable and a potential 'hazard'.

Kind Regards, John