Main RCCB tripping on r1+r2

[Bacon]

Yes that is what we thought but didn't envisage a crossed neutral with all the circuit in open position..

Thanks for comfirming what we thought and putting my mind at rest,As iv'e never come across it before.

 

[Sidewinder]

ADS,

I always have and always will select the regulations with which I comply related to the work I am doing at the time.

I often ignore certain regs and apply others, I have always done this and always will.

BS7671 is not the be all and end all of electrical installations works.

Please realise that not all members here are installations sparks.

As I have previously stated, I have discussed live working with HSE and it is NOT completely illegal.

I regularly undertake works which do not comply with BS7671.

I am popping inhere in between authoring an engineering report for a customer. In this I will be making interpretations of the scenarios I have met, and i will be providing my opinions on these situations. I will also be providing solutions to these issues.

My solutions, may or may not comply with current legislation, as the interpretation of the scenarios will be mine, the interpretation of the legislation,s regulations, guidance and other documentations will be mine.

the recommendations will be mine. I will have to stand by these in a court of law if necessary, so I must be sure of my facts. Which I feel I am.

However, this does not preclude me from carrying PI cover of

 

[Doc Hudson]

Well, it's a 'live' test, sellers - it's not quite the same as doing a 'dead' test with most of the installation left 'live', is it. I've had enough, now, I'm off......... it's been an interesting week.

Ive learnt that it's OK to 'dead test' in a 'live' board, and we only have to follow the 'Regs' that we agree with.

:coat

When doing additions or alterations to a single circuit, surely most electricians would be working on one dead circuit whilst the rest of the installation is live? I can't see how testing a single circuit is any different to altering a single circuit, say you extend a radial, do an R1+R2 on the new longer radial whilst its isolated from the rest of the installation. I am unsure what your comment about following regs has to do with this thread? Is there a reg saying we have to isolate a whole installation to carry out any work on that board?

Doc H.

 

[Manator]

I have to agree Doc , I installed a new circuit on Monday, unable to isolate the full board because of use of the building, I did all my dead tests and live tests when connected to the new CPD, the building remained live whilst the new circuit was installed.

I also did a Ze test with all bonding in place, although I need not as the regulations allow me to do this by enquiry.

My risk assessment and CDM also allowed me to do this.

 

[kme]

Have to agree - take for example three PIRs, carried out last year, on three different hotels (in the same chain) - the smallest a single storey; 42 rooms. The largest was 15 floors, with a shopping mall, boutique area, 10 floors of 35 rooms each, car park, etc.

Would it be safer to isolate the lighting in, say, a stairwell, when testing the circuit? Or do I carry out "live" testing only? Semi-rhetorical question, as your own personal RA, or the one you have drawn up if you aren`t capable of preparing your own, should give you the best solution possible ( which is NOT always the "best possible solution").

You MUST do your work according to your capabilities ( and I`m discounting the wording of all regulatory bits for the moment) ; if you aren`t comfortable / capable / have a risk assessment showing working live - DON`T.

If an RA shows that isolating a circuit would actually INCREASE the danger - what do you do?

1. Ignore your RA, and isolate the circuit anyway.

2. Comply with the RA, and work live - you feel this to be necessary, unavoidable, and are capable to do it.

3. Comply as above - though you`ve never done this before.

4. Don`t test that circuit, and put it down as a LIM.

5. Get someone more competent to do the work for you.

I know what I did - and it ISN`T the same answer for ALL the scenarios (though two of the above answers are, IMO, a really bad judgment call).

Why this is such a point of contention, I fail to understand. AFAIAC, the EAWR`89 regs are pretty specific about live working requirements.

Does anyone disagree????

 

[Sidewinder]

They are, you can do it IF YOU ARE COMPETENT TO DO SO.

IF NOT DON'T!

I had quite an interesting debate with "OUR" (KME/Admin et al.) local HSE Senior Specialist Inspector, Electrical, on this very topic.

The funny thing is the outcome.

Anyone want to guess?

 

[kme]

Don`t need to "guess". I know the person concerned ( by rep.) ; I know you. I know what I know (more to the point - I know what my limitations are).

I know the outcome - it is written

 

[ADS]

Right, let's try and stay on topic here, because I get the feeling that arguments are being made again to make me look like a *! and to just antagonise.

I have not said you should NOT test live - the point is unnecessarily!

First, we had this:

Was with a chap doing a PIR today all was ok when doing r1+r2 on all circuits bar the lighting circuit,When he did this the main breaker tripped any ideas why this would happen.

All IR readings ok Zs all ok RCD trip times all ok.

So why R1 + R2 anyway - if you can't fully isolate - it's a PIR.

But, not knowing the full crcumstances, I said:

I think you'll have to explain what you were doing in a bit more detail.

To which I got no reply.

So I said:

I'm hoping the whole thread is going to make some sense, soon.

To which I still got no reply.

So I said:

I'm not getting how the 'main' RCCB is tripping when it should be off anyway.

Because he hadn't given any reason why it would still be closed (on), during a R1 + R2 test.

Then, the *! hits the fan and everyone starts jumping down my throat about all the different situations that you could work 'live' and what they are 'qualified' to do!!!

He asked why it might be tripping - because he left it on!!

Finally, we get the additional info, and it turns out my comment was right.

Ok this what the situation was Main RCCB on all circuit breakers in open position i.e OFF, Lighting circuit left on to see what were doing.

So it was left on - not for operational reasons, not because the installation couldn't be isolated.....but so they could see.

Yeh, I see your point, chaps, that will work as a reason to ignore EAWR!

 

[Manator]

Being able to see, would be one of the most important parts of working around any live connections. The argument comes from the last sentance of your otherwise good post, the first part I can see is fully reasonable, then you spoil it by quoting EAWR as if leaving a lighting circuit on is breaking these regulations.

Often there will be fitted a DB socket, the function of this socket?

 

[ianmacd]

If the Main RCCB was open, how did they have power to the lights? And were these the same lights they were trying to R1+R2?

 

[Doc Hudson]

I think everyones understanding of this thread would be helped if we could have a sketch showing CU layout, which isolators are on/off which circuits are physically disconnected, where any strap links are placed and position of meter probes for test undertaken. Is this possible Bacon?

Doc H.

 

[ADS]

Being able to see, would be one of the most important parts of working around any live connections. The argument comes from the last sentance of your otherwise good post, the first part I can see is fully reasonable, then you spoil it by quoting EAWR as if leaving a lighting circuit on is breaking these regulations.Often there will be fitted a DB socket, the function of this socket?

Manator,

Are you seriously suggesting that the argument that you 'needed to see what you were doing' would wash with the HSE, if your colleague was lying dead on the floor.

Not word for word, but it goes:

It is unreasonable in all the circumstances for it to be dead and

It is reasonable in all the circumstances for him to be at work on or near it while it is live

There are a multitude of alternative methods of 'lighting' a job - I'm sorry Manator, I can't agree with this.

 

[Doc Hudson]

There are a multitude of alternative methods of 'lighting' a job - I'm sorry Manator, I can't agree with this.

With modern battery & LED technology you can get some very cheap and bright head mounted torches and small battery powered directional floor standing floodlights. So I would agree alternative methods of lighting a work area should never be a difficulty.

Doc H.

 

[Bacon]

I think everyones understanding of this thread would be helped if we could have a sketch showing CU layout, which isolators are on/off which circuits are physically disconnected, where any strap links are placed and position of meter probes for test undertaken. Is this possible Bacon?Doc H.

I'll do my best if i can

---------- Post Auto-Merged at 11:27 ---------- Previous post was made at 11:24 ----------

If the Main RCCB was open, how did they have power to the lights? And were these the same lights they were trying to R1+R2?

Where did i say the Main RCCB was open?

 

[ianmacd]

Where did i say the Main RCCB was open?

You were quoted by ADS in #28 although I can not see what he quoted from.

 

[Bacon]

Never once mentioned Main RCCB was open Ian

 

[ADS]

You were quoted by ADS in #28 although I can not see what he quoted from.

Hi Ian,

The quote says "main RCCB on all circuit breakers open" mate

---------- Post Auto-Merged at 12:18 ---------- Previous post was made at 12:09 ----------

.

To be fair to others, I might be being a bit over-zealous with my implementation of 'safe isolation' here.

If all MCBs were off and just the 'main switch' was on, then I suppose it's only the 'busbar' that's live. And if the DB was configured properly, then there shouldn't be any exposed 'live' parts anyway.

I still prefer to isolate at the 'main switch' though, if possible - and I definitely would'nt be leaving a circuit 'live' whilst doing 'dead testing' - unless I absolutely had to - and then I'd probably skip the test instead.

 

[ianmacd]

Hi Ian,The quote says "main RCCB on all circuit breakers open" mate

And that is exactly what I said so where did you get that from as he is saying he never said that. Or are you very bad at punctuation and you meant "Main RCCB on, all other circuit breakers open" which is completely different.

 

[Bacon]

Ok this what the situation was Main RCCB on all circuit breakers in open position i.e OFF, Lighting circuit left on to see what were doing.All circuits bar lighting r1+r2 tested IR tested Zs tested RCBO'S tested all fine.All circuits now in open position i.e (OFF) execpt main RCCB.

Get portable light out the van to be able to see what were doing when carrying out the test on lighting circuit carry out r1+r2 on lighting circuit trips main RCCB.

All other tests carried out on lighting circuit all ok IR Zs

I'd like to meet the Spark you has never done any work or testing on a live circuit

Thats what i said.

Selective parts of a quote.

 

[ianmacd]

OMG. Please post what you mean. Missing punctuation can make something completely different. That to me reads as "Main RCCD (that is) on all circuit breakers (are) in (an) open position.....". I gather from your reply that you actually mean "Main RCCD (is) on , all (other) circuit breakers (are) in (an) open position...."

See how they are COMPLETELY Different. Now which is it?