ISSUE: RCD tripping issue with All in One

I thought I’d create a specific topic for this to try and bring to light issues with RCD trips on the All in One.

I’ve emailed GivEnergy Support today and I’ve been told that my Hager RCD doesn’t agree with the All in One.

A few of us are experiencing this and I believe there is a wider issue. If you’re experiencing trips, can you add the info below? I’ll try and add this to my support ticket to see if we can get some official guidance on this. I think this is needed for installers to be able to rectify these issues correctly.

Brand of RCD: (Hager, MK etc)
Type of RCD: (Type A/B/AC etc)
Does your RCD trip on power cut?: Y/N
Does your RCD trip on power restore?: Y/N
Does your RCD reset if you pull the Grid breaker during a power cut or simulated power cut?: Y/N/Not tested

Thanks

Hi Dean, you may want to have a look at this post as well

https://community.givenergy.cloud/d/3738-island-mode/23

https://community.givenergy.cloud/d/3478-type-a-and-type-ac-rccbrcd-experience/33

Crabtree
AC
No
No
No

Daveb01 thanks yeah, I’ve had a look but the issue is my installer is going to go off what GivEnergy are recommending for the install to be fit for purpose. So far I’ve been told that Hager RCDs don’t play nicely with the AIO and now I’ve been told that a Type A RCD should be used. But you have a Type AC RCD that doesn’t trip, so I’m concerned that the advice is conflicting and my installer will just end up going round in circles. There is a mix of people who have Type A and Type AC which trip/doesn’t trip. That doesn’t sound right to me?

As you can see in my pictures I only have 1 x main switch in CU that is 100A.

To try and narrow it down, if you have another main switch at say 63A, ask your installer to remove and try AIO again?

Daveb01 it looks like you might have RCBOs instead of MCBs so each circuit is protected. I’ve got a CU with two RCDs so it’s split. I’ll get my installer to replace the Type AC with Type A and hope it solves the issue, but doesn’t fill me with much confidence!

Brand of RCD: Wylex
Type of RCD: 3x Type AC, 1x Type A
Does your RCD trip on power cut?: Yes - Type A only
Does your RCD trip on power restore?: Don’t know - Type A wouldn’t turn back on in island mode
Does your RCD reset if you pull the Grid breaker during a power cut or simulated power cut?: Not tested

I guess the ultimate question for those with no RCD Trips is:
Does the RCD in the consumer unit still trip at all when tested? If not then that's considerably worse!
(Before the conclusion is X Brand of RCD work ok and get installed)

hoggy yeah that would be interesting. @Ivan does your new Type A RCD work if you test it on island mode?

deanjesper It will probably be Friday before I get a chance to fully test it. Will report back when done so.

I actually now have one type A (new) and another type AC RCD (original) in the split load consumer unit. Plan was to replace the tripping type AC RCD with type A (which I've done) and if successful replace the other type AC RCD (which has never tripped) with a type A - I've put that on hold for now. So will test both RCDs when on Island mode.

Ivan sounds like we have the same then, split load, 100A Type AC never trips but 63A Type AC does

I have a consumer unit stuffed full of RCBO's. (Merlin Gerin multi9 C60H's, in case it matters.)

What do people think - are these likely to be a problem with my AIO when there's a power cut?

I find it a bit concerning that a qualified installer did not test the AIO and Gateway fully to see if anything tripped elsewhere. Mine spent about 3 hours testing every circuit in the CU, then the new CU in the Garage, then the AIO and Gateway, for EPS (power cuts) etc etc, including the new earth rod, before he signed it off and went home on the last day.

All worked as designed/specified and gave me a certificate to say so. Then to my surprise came back the next day and put stickers/labels on everything and a laminated diagram on the wall with shutdown and start up procedures. Said this was a requirement for MCS now.

I hope you guys get it sorted and feel everything is safe if you get a power cut 👍😀

Daveb01 clearly not happening for some of us… otherwise they would’ve picked up the trip issue from day one! Should it not be part of the commissioning process?

Daveb01 It's a good point. I don't think my installer did any of that. Nor do I have good instructions, stickers or labels.

But at the same time - if there's a pre-existing fault that the GE kit identifies - that's not the installers problem to fix?

This is my setup in Garage and very pleased (no room for a car anymore 😀

Daveb01 Nice!

hoggy

26Left

deanjesper

So I replicated a power cut again to test if my RCDs worked when in ‘island mode”.

On isolating the grid, some flicker occurred on an LED bulb but everything else changed over seamlessly – modem, router, cooker clocks etc all continued without interruption and neither of my Type A nor Type AC RCDs tripped. Everything was working fine.

I then tested if the RCDs would trip by using a cheap socket tester I have which has the facility to provoke a RCD test. I have 3 ring mains and on plugging into each circuit the tester indicated a fault, that each circuit had a Live Neutral reverse! I tried to provoke a trip of the RCD but could not using the socket tester. I then tested each of the RCDs by pressing the test button each and both tripped. Both were able to be reset without any problem.

On restoring the grid power, everything changed over fine. Then, about 10 seconds later the PV breaker in the Gateway switched itself off. It reset without a problem.

Now that the grid was restored, I checked each of the ring mains again and now the tester indicated they were all working fine. I was also able to trip the RCDs by the test function on the socket tester.

So, in summary, all functionality remained when in island mode – nothing tripped, everything worked. However, the cheap socket tester indicated a Live Neutral reverse and a RCD trip could not be provoked by the tester when in island mode. My circuits have been successfully tested in past and don't have a "real" Live Neutral reverse hence the reason for this indicated fault is beyond my knowledge but for now I’m guessing it is due to how island mode produces 120v live to -120v neutral???

Another question is are the RCDs (of any type) still fully functional under this type of operation?
The reason for the PV breaker trip also needs to be explained.

I’d like to understand some more before I ask my installer/GE for advice. Grateful for any comments from others.

Ivan for some weird reason, GE decided to make the AIO run in split phase during island mode, here's the direct response I received from GE when I queried the behaviour:

In island mode, the voltages are slightly different.
L-E is 120V
N-E is 120V
L-N – remains at 240v

Its called IT earthing, or split phase.
RCDs operate normally, as they care for N—L current imbalance

Blasteh Thank you - useful to know.

Ivan interesting - maybe the socket tester doesn’t understand split phase and gets confused, maybe like a Type AC RCD?

Socket tester will just be picking up voltage on the neutral and getting confused.
Good that the RCD tripped, however as for "will they all work" I can't say, in theory they should (trip times & currents - still comply? Not sure how RCD/MFT testers react to split phase if I'm honest. They too may not even run tests!)

Equally IT installations are really quite niche and certainly not the norm in domestic. They are more for high reliability supplies for things like Hospitals as they offer the ability to ride through certain faults BUT as ever the catch is they generally need additional monitoring systems in place and a lot of thought from the designer to keep touch voltages low.
One I need to go dust off some books in the attic to ponder...

(Not trying to be a thorn in GEs side but it is an odd way of doing something (and i like odd) that nobody else does (which can vary from 'because nobodies thought of it before' to 'because its a terrible idea' i guess?) )

Ok I think I might’ve found an issue that may cause my main RCD to trip in the house when the AIO goes off grid. Someone tell me if I’m wrong or not.

In my garage I have a separate CU. I’ve just tried to test the RCD in there and the test button doesn’t trip the RCD. I then used a socket tester to test the RCD and it didn’t trip in the garage, only in the house. Could this faulty RCD cause the house to trip when the AIO goes off grid?

Oooo what do I win? https://community.givenergy.cloud/d/3738-island-mode/18
Note: you can still try sequentially turning MCBs on while toggling off grid mode, you may get lucky in narrowing it down. My bet is "garage" personally as a wild stab.

Anyway, answer - probably/potentially. It needs fixing put it that way!

Note: For those not put to sleep by earthing arrangements, the nearest plain English information using something as near as you can to how the AIO works is: https://electrical.theiet.org/wiring-matters/years/2020/82-september-2020/mythbusters-6/
As you can see it gets quite complex and TBH I'd debate it's a true IT system, more a TN-S in island mode similar to Figure 1 because you have a rod deployed from the gateway.

hoggy you win a very smug look!!

Yeah it’s the RCD in the garage. I flipped it down and forced the AIO off grid and hey presto, no trip!

It’s an old consumer unit in the garage and finding a replacement RCD is probably going to be tricky. Does there even need to be an RCD in the garage if the MCB in the house is already protected by an RCD?

If the feed to the garage is already protected by the house RCD then you may not need another RCD.
Trouble is a garage fault may take out the house rather than the garage if you dont have one in the garage.
Mind you I am not sure if 2 RCDs in series will be able to discriminate, so even if if you have a garage fault, the house RCD may trip and the garage one not. See point 4
https://electrical.theiet.org/media/1683/understanding-rcds.pdf

I’ve had an an electrician here today who found and isolated 2 N-E faults that were presenting in island mode and tripping the Type A RCD. The good news is that the house now goes in and out of island mode without RCDs trips.

So my answers are updated below.

His testing equipment couldn’t check whether the RCDs will trip in island mode, because it didn’t like the fact that it was running split phase. They tested fine with grid supply.

I’m going to take it up with my installer to why they didn’t replace the RCDs from type AC to type A.

26Left Brand of RCD: Wylex
Type of RCD: 3x Type AC, 1x Type A
Does your RCD trip on power cut?: Yes - Type A only NO
Does your RCD trip on power restore?: Don’t know - Type A wouldn’t turn back on in island mode NO
Does your RCD reset if you pull the Grid breaker during a power cut or simulated power cut?: Not tested

26Left why were the N-E faults not present in grid mode?

GivEnergy should add test in island mode to their commissioning process so we don’t end up finding these issues when there’s a power cut!

When people are testing island mode are you doing this by physically switching off the incoming supply (at the isolation switch by the meter or in the gateway?) Or via a software means?

ma9mwah I flip the Grid breaker down in the Gateway. I did “force Off grid” in the portal once and because the RCD tripped I panicked as the internet went down! So do the former first!

deanjesper because… science.

https://community.givenergy.cloud/d/3478-type-a-and-type-ac-rccbrcd-experience/35

Insufficient current N-E when in grid mode, but in island mode and the AIO using split phase, there’s enough.

ma9mwah I got my installer back to insert a dipole switch between the smart meter and the gateway for safety as well as testing, as a different electrician discovered that there are still live elements inside the gateway even when all the gateway breakers are off. So I use (and trust) that DP switch to simulate grid failure.

See this https://community.givenergy.cloud/d/2956-gateway-compliance-with-regs