Bi and Omni directional RCD's how can one tell what has been fitted.

Joined
27 Jan 2008
Messages
25,285
Reaction score
2,956
Location
Llanfair Caereinion, Nr Welshpool
Country
United Kingdom
We watch you tube, and we are told how BS7671:2018 now has a 3rd amendment mainly about omni or bi directional RCD's and the dangers of using omni with solar installs, look for info on the RCD we see type AC, A, F, B, and B+ and what it shows on the casing to work out which you have, but as to omni or bi not a clue what to look for.
 
Sponsored Links
We watch you tube, and we are told how BS7671:2018 now has a 3rd amendment mainly about omni or bi directional RCD's and the dangers of using omni with solar installs, look for info on the RCD we see type AC, A, F, B, and B+ and what it shows on the casing to work out which you have, but as to omni or bi not a clue what to look for.
Do "omnidirectional" RCDs actually exist? I've certainly never heard of them, and Mr Google also struggles to find anything
 
Sponsored Links
I would say they might exist but if they do then they would have to have some very complex electronics to evaluate in which direction the unbalanced power was flowing.
That's what I thought and, as I wrote, I have yet to really find any evidence that they do exist - so, even if they do, they clearly can't be significantly 'available' (and I suspect might be extremely expensive, even if they do exist).
 
What is meant by the term "directional" with regard to RCDs?
A very good question.

As bernard has said, they would have to be complex to be able to distinguish between direction of current flow but, even if they could do that, I still don't know what it would mean - it would seem very odd if they 'ignored' residual currents travelling in one direction, wouldn't it?

I think eric needs to tell us where he heard about this alleged animal!
 
This question has cropped up a few times and all we seem to have come up with is which side of the isolation the internal control circuit is.
 
The draft of AMD3 will be available for public comment from tomorrow until 5 June. Will be published later this year.
 
I believe he did. Amendment 3.
That's what he wrote - but does he have a crystal ball - or has he perhaps seen a 'leak' of the draft of Amd 3 ?

Anyway, whatever the draft of Amd 3 might say, as I wrote, I've yet to find convincing evidence that the animals actually exist, let are lone are ';available' (at an affordable price) :)
 
, I've yet to find convincing evidence that the animals actually exist, let are lone are ';available' (at an affordable price) :)

Plenty available everywhere, some of which have been on the market for years.
 
Plenty available everywhere, some of which have been on the market for years.
Thanks. I think the mistake I made, based on what eric had written, was to search just for "omnidirectional" which yielded essentially no hits, and I therefore didn't 'bother' to also search for bi-directional !

So what does "bidirectional' actually mean in relation to these devices?
 
BEAMA published a tech update last year and there was an article in wiring matters 99. The term is unidirectional, not omni. The amendment was announced a short while back. Hi-directional means the device works in both directions so is suitable for prosumer units. Unidirectional devices have an indicator to show the direction from supply to load, such as an arrow.
 
Last edited:
I have looked at the pictures, and I fail to see how one can know if the RCD or RCBO is Bi-directional, the ones @flameport shows still show out on them, so if doing an EICR how does one know if correct one is fitted?

It seems most rely on the output switching off to stop current flow through the test button, if tripping does not remove power from output then current can still flow.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top