Burnt Out Neutral On Rcbo

[Y6 1878]

The overload suggestion is exactly what I though but as you said should have tripped on overload before the failure. As you also said surely the device should work as intended without the damage shown in pics regardless of and faults overload, short circuit etc. I would happily swap them for another make but with 137 fitted have to find somebody to foot the bill. Nightmare!!

 

[NozSpark]

I guess that others like me have found that we come across burnt out neutrals much more often than burnt out lines.. I certainly find burnt out neutrals on shower isolator switches, not too many RCDs or RCBOs though but I have come across the odd one or two..

I don't personally put too much faith in the idea that people don't tighten neutrals quite as much,,, I think that there must be some other reason however I don't know what it is.

As for who's going to pay the cost of replacement.... Have you ever seen a caravan box that's on fire? I have had one go up when I was on site and while we turned off the power and the fire went out pretty quickly we did find that the mobile home had scorch marks up the side...

For that reason we wired all the hook up boxes MCB - RCD instead of the more traditional RCD - MCB

 

[Sidewinder]

Harmonics?

Lots of LED lights in the caravans?

Put a power analyser on one.

However, a 10A MCB will take 14.5A before it  ever trips, so, it should carry that current if it meets the requirements of the standard, even though it is an RCBO.

 

[Y6 1878]

That's a really good suggestion a power analyser would tell me what's going on with current flow etc.

Any ideas where the best place to get a power analyser from?.

 

[kerching]

I think you can hire them fro MM at ISSSWWW one of the forum sponsors

 

[Sidewinder]

ISSWWW.co.uk for definite, forum sponsor Megger Mark.

I would suggest that you get one with at least 2 clamps capable of harmonics though so that you can see what is going on with the neutral as well as the phase.

 

[Blue Duck]

Have you tried a different make of DP RCBO?

The more I read this & the other thread on the rocket scientist forum I'm convinced its kettles!

 

[Y6 1878]

Trying different RCBOS is not going to explain why these are frying so badly, but as it happens we have fitted two different makes in to separate boxes. Explain kettles??? Lol.

 

[Y6 1878]

Actually I think you may be right!!! The amount of brews I've drunk supplied by happy campers I've probably caused the problem, buying a flask tomorrow!!

 

[Y6 1878]

Any other ideas regarding this problem?? I've asked every electrician that's been unfortunate enough to bump into me over the last couple of weeks and nobody seems to have a definate answer, just a few more details in case they make something clearer.

- 10A 30ma RCBO

- two module width

- Double pole

- Rolec brand????

- Melting on outgoing side of neutral

- no nuisance tripping before total failure

- when failed device left Open circuit

- All hook up boxes TT

- only one RCBO per box

- and no flying leads to RCBOS

Any further ideas would be great cheers

 

[kerching]

Is it possible to put a thermal imaging camera on one when running at normal load and again at full load?

Are screws torqued up?

Is torque setting actually correct?.....compare with setting from another manuf?

What cable type/size goes into terminal?

Dissimilar metals?

Creep?

Why not get the suppliers to come and have a look?

Definitely an odd one

 

[Blue Duck]

Can you set up a test rig at home?

 

[ProDave]

This thread is just going round in circles.

It's only a 10A maximum load, so gross overload is unlikely to be the cause.

So it can only be faulty equipment.

I would be throwing the lot back at the manufacturer.

In the mean time I would have fitted a different make of rcbo in the ones that have failed and see if any of those fail?

And as above take one of the suspect ones home (one that hasn't failed yet) and run some load tests to see if there's any sign of it getting at all warm with a 10A load for some time.

Above all I would be logging the time I spend and preparing a report, with a view to getting that paid by the manufacturer (if not the site owner)

 

[Username 0]

Hi, I've just been called out to 2x Rolec rcbo's that have burn't out on the neutral. We have a record of the torque setting checks form the start of the season. 

Have Rolec replaced parts for anyone else ? We're now on about the 10th rcbo replacement this year due to test buttons not working too!!! 

 

[Doc Hudson]

Hi, I've just been called out to 2x Rolec rcbo's that have burn't out on the neutral. We have a record of the torque setting checks form the start of the season. 

Have Rolec replaced parts for anyone else ? We're now on about the 10th rcbo replacement this year due to test buttons not working too!!! 

Welcome to the forum, thanks for your input, It does sound as though these products have some issues that need resolving. What part of the country are you in, are your replacements all on the same site or at different sites, (same incoming supply source or multiple sources).

Doc H.

 

[Username 0]

Hi Doc, I've not contacted Rolec personally but my wholesaler has So I wont pass judgement on Rolec yet!!

We fitted 150+ Rolec hook up points with 10 amp Rolec Rcbos in them. All the same size and rating but from different supply boxes from different phases. 

Just over 1 year on and have replaced 15+ from our stock to date. 4 burned neutrals and the rest because of test buttons not working. 

and we're in sunny Devon. 

 

[Andy™]

sounds like a major problem with them... wonder if they will be responsible like electrium and recall them and pay for the replacement work?

 

[Username 0]

We will find out, I sure hope they pay for some of our time or this will cost us a fortune!!