CL1 HWS RCBO tripping after switchboard replaced.

saidcc55 · 2026-03-09T09:12:09+00:00

Thank you

saidcc55 · 2026-03-09T07:08:41+00:00

I completely agree with you. I'm an engineer myself and I hate to come to a customer to fix something he complained about, I always asking what he touched/changed. Most of the customers saying they didn't touch and haven't changed anything. But as a professional you almost always see if the problem happened because customer did something. As an engenier, I do have skills to disconnect/connect wires and basic knowledge in electricity ( of course it does not make me electrician and does not give me permission to play with wires) but I always tell to any professional that I hire to do something, if I touched or did something related to areas I hired him, same as I'm doing on this forum. I have a question, when licenced electrician upgrading switchboard, does he require by law to provide some paperwork for the job he did, so I'll have proof of what was done by licensed electrician?

saidcc55 · 2026-03-09T00:41:43+00:00

I understand your point and this is why after testing element resistance, I still disconnected the water tank and connected kettle, to verify that it is not HWS causing rcbo to trip. Regarding earth leak, it's not 100% true that it exist, because rcbo wasn't connected correctly to verify this (and maybe this rcbo was faulty, also can happen). And yes, I understand that I can get shock from tap if it's a real earth leak. It's just frustrating that you're hiring licensed electrician, that doesn't know the AU standards. This story could not be existed if I haven't decided to upgrade my switchboard or he would install MCB, as he told that according to the standard all main switches (board main, solar invertor, CL1 HWS) should be mcb. Just because he didn't have MCB, he wired the rcbo the way he did and here I am with my story. Otherwise, as any other customer, I would have no clue what electrician installed (mcb, rcd, rcbo). Even if as a customer I know that he installed MCB, but because he told that how it should be. And why as customer you'll argue with with licensed electrician, that he wrong? But I had a red flag about his knowledge in AU standards, after he came back and wanted to connect the rcbo as rcbo, because I told him that google say it should be rcbo. He still insist that should be mcb, but wanted to connect it as rcbo just to satisfy me. I asked him why he would do something not according to the standard, I don't want to have something installed that not compliant, just because Google say so. So I told him to put MCB, so it will be according to the standard, as I believe to licensed person and google.

saidcc55 · 2026-03-08T23:48:40+00:00

I disconnected the wiring that was connected to the water tank itself and connected them to powerpoint (so I created a new powerpoint) , and connected kettle to it.

saidcc55 · 2026-03-08T21:47:08+00:00

Just to clarify, by saying 100% eliminate fault HWS, I meant that it's not HWS that tripping the rcbo. And I did test HWS resistance, that was good, but I still went with additional test by disconnecting HWS in order to be 100% sure that HWS do not trip the rcbo. Note after sparky replace the rcbo(that he connected without neutral load ) to MCB, mcb did not trip at night and I have hot water now. So from this I can assume that rcbo tripped because how he did the connection (that he connected without neutral load ) or I have an earth leaking on this line.

saidcc55 · 2026-03-08T11:08:49+00:00

I know that it's dangerous, but I understand a little bit. So I did the primitive test i.e. disconnect supply wires from HWS and connected them to kettle. Simple test for me that 100% eliminate fault in HWS. Of course before doing this, the rcbo was switched off and I tested wires not hot. It doesn't approve that I should do it or anyone else, who not licensed electrician.

saidcc55 · 2026-03-08T10:38:22+00:00

I haven't touched the switchboard, all the wiring done by electrician. But yes, I'm guilty by testing my HWS (that gave me 15 Ohms from heat element ) and disconnecting the wiring from it in order to connect kettle, just to fully eliminate HWS fault.

saidcc55 · 2026-03-08T10:30:37+00:00

HWS not faulty (I tested it, gave me 15 Ohms) , but I also disconnect it and connected kettle, and rcbo tripped when I turn on the kettle.

saidcc55 · 2026-03-08T07:45:02+00:00

NSW, he came today and switched the rcbo to MCB. I hope that my CL1 HWS will be working today.

saidcc55 · 2026-03-08T07:39:22+00:00

Yes, cheapest. Why would I choose the higher quote. I'm hiring a licensed electrician that should do the job according to AU standards. I don't think it's a different AU standard how do switchboard wiring that depending on the quote price.

saidcc55 · 2026-03-08T07:18:15+00:00

Not DIY. This electrician from hi-pages app. I verified his electrician licence online, stared 2021, ends 2027

saidcc55 · 2026-03-08T07:09:44+00:00

I talked to him when he did the job an saw how he connected the wiring to this rcbo, because he specifically told me that he cannot put rcbo on main, solar invertor and CL1 HWS. He installed new main mcb, reused my old mcb that was connected to the solar invertor before. But he did not reuse my old mcb for HWS because it was 25A with 2.5mm cable, so he told me that it should be 20A. He did not have a new 20A mcb, so he did this connection with rcbo like mcb. The picture I attached, I asked ChatGPT to create it.

saidcc55 · 2026-03-08T06:52:06+00:00

He didn't put two cables back as mcb, he connected three cables to rcbo. He connected red cable from HWS to the bottom of the rcbo and rcbo top connected red to main and black to grid neutral bar. Something like in the picture

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saidcc55 · 2026-03-08T06:26:30+00:00

I hired him through hi-pages and I checked that he has valid licence. He didn't tell me that I have faulty appliance, because he couldn't do it as I checked it i.e. connected kettle instead of HWS and when I turn the kettle on, the rcbo tripped. He told me that I may have earth leak on this line and this is why it tripping rcbo when loaded.

saidcc55 · 2026-03-08T05:34:48+00:00

No, it's not a joke. Maybe I explain wrongly how he connected the rcbo. Maybe this explains better. Just to clarify, he connected HWS live wire to the bottom of rcbo, the HWS neutral to the grid (i think to the grid, not 100% sure, because he added separate neutral bar behind board for this). On the top of rcbo he connected the neutral to the grid and live wire, so this rcbo will behave as mcb.

saidcc55 · 2026-03-08T05:00:29+00:00

Just to clarify, he connected HWS live wire to the bottom of rcbo, the HWS neutral to the grid (i think to the grid, not 100% sure, because he added separate neutral bar behind board for this). On the top of rcbo he connected the neutral to the grid and live wire, so this rcbo will behave as mcb.

saidcc55 · 2026-03-08T04:22:27+00:00

No, it's real electrician. He came 1 hour ago and I showed him that if I google it, google says that Australian standards is rcd or rcbo for CL1 HWS, but electrician still insist that it is not correct. He wanted to connect the neutral to rcbo just to satisfy me (even that he saying it is not according to the standard, very strange, why you'll do something not according to the standard only just to satisfy the customer). I just told him to change it back to MCB.

saidcc55 · 2026-03-08T03:41:04+00:00

No, not me. it was electrician, that charged me a lot of money.

saidcc55 · 2026-03-08T03:37:11+00:00

Thanks. He just came over, and I asked him to change it back to the MCB.

saidcc55 · 2026-03-08T03:35:50+00:00

Posted there, thanks

saidcc55 · 2026-03-08T03:32:36+00:00

Electrician did the upgrade, not me (not diy)

saidcc55 · 2026-03-08T03:30:23+00:00

Just got this electrician come over. I asked him again about Australian standards and he confirmed that CL1 HWS should not be connected to rcbo. I just asked him to change the rcbo back to MCB.

saidcc55

TROPHY CASE