Shower RCD tripping

[Lacessit]

As I've said on another thread, after the Thai electrician installed a RCD on the shower circuit, the RCD tripped out as soon as I turned the water on.

He came again today, did some fiddling, problem solved. Or is it?

Photos of the fuse box before and after he fiddled. Still looks like a bowl of spaghetti to me. Although the coiled black lead from the RCD seems to be in a different terminal. It's a bticino fuse box. Comments welcome.

[Crossy]

Can you show a decent image of how the RCBO has been wired please.

 

Is the blue wire the neutral tail of the RCBO? Does it go to the neutral bar? (or is that the curly black pigtail)

 

Is the shower neutral connected to the neutral out of the RCBO? Are you sure the correct neutral has been used?

 

It is of course possible the shower is faulty, disconnect the shower and replace it with a 60W lamp, does the RCBO stay on?

 

EDIT Ah, I see you say the sparks has been back and "fixed" it, any idea what he did? Does the RCBO trip on the "Test" button?

 

[bankruatsteve]

I can't make out much from your photos.  But, if the (is it) RCBO can be turned on then it seems the CU wiring is OK.  Maybe open up your shower unit (with circuit power off) and confirm wires are hooked up properly and clean any dust, gecko, ants that might have come in.  Could be a defective unit.

 

Oops.  Sorry Crossy didn't see you.

Edited August 5, 2018 by bankruatsteve

[Lacessit]

Sorry folks. I omitted to say there is nothing wrong with the shower heater unit. It's fairly new, Hitachi, and has its own trip switch as part of the unit. I simply wanted an RCD in the main fuse box because there was nothing there. Leading on from the unfortunate Brit who was electrocuted in Khon Kaen.

The RCD or RCBO does trip on the test button. The curly black wire is part of the RCD, I have no idea whether the blue wire is active or neutral. I assume it's not earth.

 

[Crossy]

If it trips on the button and stays on when the shower is working then it's likely wired right.

 

One last check, turning the RCBO off does stop the shower heater doesn't it?

 

[Lacessit]

1 hour ago, Crossy said:

If it trips on the button and stays on when the shower is working then it's likely wired right.

 

One last check, turning the RCBO off does stop the shower heater doesn't it?

 

Yes

[Led Lolly Yellow Lolly]

Trying to figure things out from your photos gives me a headache, but it looks to me like you have a TT system, in which case you shouldn't be relying a single pole RCBO. Get someone in that knows what they're doing, I know how hard that is but this is a shower, find a pro.

Edited August 8, 2018 by NilSS

[Crossy]

@NilSS please explain. Remember this is a secondary RCBO (not an incomer which would need to be 2-pole), it would be permitted in the UK (the No2 nanny state of electrical installation).

 

 Do you have a link for a 2-pole RCBO that fits in a single slot of a Square-D box (and is available in Thailand)?

 

[Led Lolly Yellow Lolly]

A N-E fault is detected but left in circuit, which can be substantial on a TT system.

[Crossy]

2 minutes ago, NilSS said:

A N-E fault is detected but left in circuit, which can be substantial on a TT system.

Agreed. But the single-pole unit is significantly more safe than no RCBO at all.

 

Do Square-D even make a 2-pole RCBO that fits in one slot? (and can you get them here)

[Led Lolly Yellow Lolly]

I've never seen one, but then I'm not looking. I either deploy TN-CS/MEN or use 2-pole primaries otherwise.

Edited August 8, 2018 by NilSS

[Crossy]

Don't Panic!!

 

IMPORTANT NOTE

Whilst NilSS comment about N-E faults is perfectly valid. A N-E fault which is likely to do you any harm (other than being a pain to locate) is vanishingly rare, certainly not worth worrying about if you have only single-pole RCBOs (new installations are supposed to be MEN anyway so it's not an issue).

 

I'm 99% sure Square-D don't do a 2-pole plug-in RCBO that fits one slot, their RCBO incomers are, as required, 2-pole.