Hot tub tripping, but also working… crossed Neutral?

[Refinedgent]

Are Neutral and earth crossed or does it change over mid way? On the RCD black is earth and grey is Neutral. In the hot tub Grey is earth and Black Neutral?

Yep exactly, so they are swapped from the RCD to the tub

 

[IJWS15]

Have I missed something or is the OP routing the return (blue) cable through the local RCD as well? Not an electrician but surely it won't function as an RCD without this being done.

 

[EFLImpudence]

Have I missed something or is the OP routing the return (blue) cable through the local RCD as well?

Yes, the thick blue connects to the bottom of the RCD - although I would think a bit it ought to be visible despite the angle

 

[Refinedgent]

Yes, the thick blue connects to the bottom of the RCD - although I would think a bit it ought to be visible despite the angle

Yep thick blue goes behind RCD into bottom right (it came wired as such)

hot tub Mai trance guy came round and can’t fathom it,
he thinks it’s possibly the circuit board, or maybe transformer that’s on the circuit board but cant figure it out as it basically shopulent be working, but clearly is. He conducted all the isolation tests I did and to no avail, it’s still tripping when connected ‘correctly’

but when earth and N are swapped at tub it works.

I’m getting an electrician round Tuesday to take a look on the off chance there something untoward at the main CU, maybe N and Earth are swapped for example or the wire at CU is somehow shorted.

otherwise it’s Linley the motherboard though seems bizarre the motherboard is faulty yet functions correctly….

 

[EFLImpudence]

it’s still tripping when connected ‘correctly’ ...but when earth and N are swapped at tub it works.

No it doesn't. It works with the colours not as you think they should be.

Have you not checked which is actually Neutral and which is actually Earth YET?

The colours must be reversed somewhere along the way.

 

[Refinedgent]

No it doesn't. It works with the colours not as you think they should be.

Have you not checked which is actually Neutral and which is actually Earth YET?

The colours must be reversed somewhere along the way.

My multimeter is not working sigh, so can’t check this currently which is a pain.
I have an electrician who is coming Tuesday to fully check it as the hot tub guys are apparently ‘not trained in electrics’ which is somewhat unfathomable but anyway…

I think the most likely outcome is N and E are indeed swapped somewhere upstream
OR
Motherboard/transformer in tub is ‘broken’ and may need replacing, which is a PITA as they are not cheap
Although terribly frustrating as clearly it’s not that broken if conn ted to live and it functions!

 

[EFLImpudence]

In the beginning, was written:

The tub has its own 32Amp fuse on an RCD fuse board in an outbuilding, nothing else is on this fuse, tub only.
The wiring from this then goes outside to the tub to another smaller IP65 RCD with a DIN rail and 40A 30mA breaker.
This breaker switch does not function… regardless of switch on or off, Tub remains on.

We then noticed that the Line(live) supply and load conductors were connected together and not running through the RCD - ok -

BUT the Neutral was so why did that not switch off the tub?

UNLESS the tub really was connected to L and E, but then the first RCD would have tripped so it can't be.

(if the 32Amp fuse in main outhouse is switched tub powers on/off as it should)
I didn’t think too much of this and guessed the exterior fused switch was dead or it simply wasn’t wired up Or some such.

Upon isolating the supply and opening up the exterior British General box, I replaced the fuse with a like for like swap 40A 30mA fuse….
still nothing.. the new fuse wasn’t switching anything…. Tub was working great but this switch was doing nothing…

I then checked the tub itself just on off chance it was wired incorrectly and sure enough
Live was correct, but Neutral and Earth were swapped, hence switch wasn’t vitally switching anything. Odd I thought… I swapped them round so now correctly wired….
now main breaker is tripping.

That just confirms what I have been saying that the colours are swapped somewhere,

but why did the Neutral being switched not turn off the tub?

 

[Refinedgent]

In the beginning, was written:


We then noticed that the Line(live) supply and load conductors were connected together and not running through the RCD - ok -

BUT the Neutral was so why did that not switch off the tub?

UNLESS the tub really was connected to L and E, but then the first RCD would have tripped so it can't be.



That just confirms what I have been saying that the colours are swapped somewhere,

but why did the Neutral being switched not turn off the tub?

Well indeed,
I did think this,

I thought hmm the live has been bypassed ok,
but the Neutral definitely hasn’t… shouldn’t the switch when flipped turn off the tub? But nope nothing

Makes me think, perhaps if the N and E are reversed up stream this would mean in fact currently it’s just the Earth that is connected to RCD so would have no effect When switched?

 

[JohnW2]

We then noticed that the Line(live) supply and load conductors were connected together and not running through the RCD - ok -
BUT the Neutral was so why did that not switch off the tub?
UNLESS the tub really was connected to L and E, but then the first RCD would have tripped so it can't be.

Quite so.

Since the RCD was not switching off the tub, one has to conclude that the tub was returning its current through something other than the conductor 'marked' as neutral. Since it's hard to believe that there would be any additional neutral conductor anywhere, that would seem to make it very likely that current was being retune via the 'earth' conductor.

As you say, one then has to explain why the other (upstream) RCD didn't trip. That means that all of the return current must have been going through the 'N side' of that other (upstream) RCD - and the only way I can think of that could make that happen would be if the conductor 'marked' as 'earth' in the vicinity of the 'first' (downstream) RCD (i.e. that carrying the tub's return current) were connected to the other (upstream RCD's Neutral terminal.

Is that not the case? Can you think of any alternative explanations [I am, of course, assuming that the upstream RCD actually 'works']

Kind Regards, John

 

[EFLImpudence]

Well indeed,
I did think this,

I overlooked that at the time.

I thought hmm the live has been bypassed ok,
but the Neutral definitely hasn’t… shouldn’t the switch when flipped turn off the tub? But nope nothing

It should.

Makes me think, perhaps if the N and E are reversed up stream this would mean in fact currently it’s just the Earth that is connected to RCD so would have no effect When switched?

Depends.

 

[Refinedgent]

Quite so.

Since the RCD was not switching off the tub, one has to conclude that the tub was returning its current through something other than the conductor 'marked' as neutral. Since it's hard to believe that there would be any additional neutral conductor anywhere, that would seem to make it very likely that current was being retune via the 'earth' conductor.

As you say, one then has to explain why the other (upstream) RCD didn't trip. That means that all of the return current must have been going through the 'N side' of that other (upstream) RCD - and the only way I can think of that could make that happen would be if the conductor 'marked' as 'earth' in the vicinity of the 'first' (downstream) RCD (i.e. that carrying the tub's return current) were connected to the other (upstream RCD's Neutral terminal.

Is that not the case? Can you think of any alternative explanations [I am, of course, assuming that the upstream RCD actually 'works']

Kind Regards, John

So in effect, it may be worth assuming the N and E wires coming from the main CU are in fact incorrectly labelled and are in reverse.
I guess I’ll try wiring these up the other way round as they are currently and see if this solves anything

 

[EFLImpudence]

So in effect, it may be worth assuming the N and E wires coming from the main CU are in fact incorrectly labelled and are in reverse.
I guess I’ll try wiring these up the other way round as they are currently and see if this solves anything

NO.

You must determine which is which first; not just swap wires willy-nilly.

Start at the CU and wire it properly.

 

[EFLImpudence]

Since the RCD was not switching off the tub, one has to conclude that the tub was returning its current through something other than the conductor 'marked' as neutral. Since it's hard to believe that there would be any additional neutral conductor anywhere, that would seem to make it very likely that current was being retune via the 'earth' conductor.

Yes.

As you say, one then has to explain why the other (upstream) RCD didn't trip. That means that all of the return current must have been going through the 'N side' of that other (upstream) RCD - and the only way I can think of that could make that happen would be if the conductor 'marked' as 'earth' in the vicinity of the 'first' (downstream) RCD (i.e. that carrying the tub's return current) were connected to the other (upstream RCD's Neutral terminal.

Yes.

Is that not the case? Can you think of any alternative explanations [I am, of course, assuming that the upstream RCD actually 'works']

Yes, it works. It is difficult to think of all the options.

 

[Refinedgent]

NO.

You must determine which is which first; not just swap wires willy-nilly.

Start at the CU and wire it properly.

I know my limits and opening up a multi-fuse CU is where I draw the line I think,
not confident in opening it up etc so will wait for Tuesday when I have a proper electrician round to examine it.

I’m hoping it’s just as simple as the N and E being wrong way round,
my concern is if it is indeed wired up as it should be, (ie wires are labelled correctly) why the hell is it working when wired up with N and E the wrong way round… makes no sense!
is it possible in the current scenario this could occur if N and E were touching somewhere along the line?

 

[Refinedgent]

Yes.


Yes.


Yes, it works. It is difficult to think of all the options.

Does this not also indicate that indeed it likely downstream N and E wires are incorrectly labelled and require reversing?