Put up the EIC results and a photograph of the CU and we will tell you!
Electrical issue! Help!
- Thread starter pundabuyer
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Put up the EIC results and a photograph of the CU and we will tell you!
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For more than 24 months now (?), you are not supposed to have a single 30mA RCD protecting an entire property - you should have a minimum of two so as to cause the least inconvenience when something does trip.
With as few as five circuits it would be considered best practice to use RCBO's (an MCB and RCD combined) for each circuit, using a standard DP main switch. A fault on one circuit would remain on that circuit and not interfere with the others.
You could instead use a '17th edition' dual split load - a main switch and then two banks of MCB's protected by two RCD's.
Your consumer unit does not comply as it is.
What is the rating of the main RCD in the consumer unit? 30mA, 100mA etc?
As you have been mixing plaster, is there a good chance you have got wet plaster or water into sockets, or your extension lead?
It sounds like you have a N-E fault of some impedance, which would cause the RCD to trip as more load is introduced.
With as few as five circuits it would be considered best practice to use RCBO's (an MCB and RCD combined) for each circuit, using a standard DP main switch. A fault on one circuit would remain on that circuit and not interfere with the others.
You could instead use a '17th edition' dual split load - a main switch and then two banks of MCB's protected by two RCD's.
Your consumer unit does not comply as it is.
What is the rating of the main RCD in the consumer unit? 30mA, 100mA etc?
As you have been mixing plaster, is there a good chance you have got wet plaster or water into sockets, or your extension lead?
It sounds like you have a N-E fault of some impedance, which would cause the RCD to trip as more load is introduced.
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First I will try to explain the earth neutral fault
The picture is taken from an electronics program and every wire I have given a resistance of 1 ohm as all wires have some resistance and the small faulty item 3900 ohm with the large item which I have given a value of 2000 ohm switched off the ammeter recording the fault current is below the 0.030 A which will cause a RCD to trip. However when the switch is closed the extra current drawn lifts the fault current to over the 0.030 A so the RCD will trip.
It is this that makes it so hard to work out what is making a trip open. Now wet plaster is likely to conduct some small current which could make a fault become apparent when any load is put on the circuit. The leakage is so small it really needs a special meter that uses 500 volt to find this fault so likely you will need an electrician.
The electrician you have had working for you should have provided you with a schedule of test results and the new electrician using these will quickly be able to locate where the change is and so where the fault lies.
This paperwork if any work in a kitchen bathroom outside or on a consumer unit has been done will also have been sent to the local authority building control. There are two ways to do this. Either the electrician becomes a member of a scheme which allows him to self certify the work and send the forms once completed to LABC or before starting the work one contacts the LABC who charges you silly fees and come when completed to issue a completion certificate. It is down to the owner to notify building control but normally the electrician will do it for the owner. If the electrician has the name of any of the scheme operators on his paperwork or van then it is down to him to notify LABC.
The same applies to builders they will normally do the LABC work for you but if they don't it's you who pays to correct it unless you can prove they were contracted to do that for you.
It is this that makes it so hard to work out what is making a trip open. Now wet plaster is likely to conduct some small current which could make a fault become apparent when any load is put on the circuit. The leakage is so small it really needs a special meter that uses 500 volt to find this fault so likely you will need an electrician.
The electrician you have had working for you should have provided you with a schedule of test results and the new electrician using these will quickly be able to locate where the change is and so where the fault lies.
This paperwork if any work in a kitchen bathroom outside or on a consumer unit has been done will also have been sent to the local authority building control. There are two ways to do this. Either the electrician becomes a member of a scheme which allows him to self certify the work and send the forms once completed to LABC or before starting the work one contacts the LABC who charges you silly fees and come when completed to issue a completion certificate. It is down to the owner to notify building control but normally the electrician will do it for the owner. If the electrician has the name of any of the scheme operators on his paperwork or van then it is down to him to notify LABC.
The same applies to builders they will normally do the LABC work for you but if they don't it's you who pays to correct it unless you can prove they were contracted to do that for you.
T
tonyelectric
To the OP, to address this issue of the wrong type of CU, the other commentators here are quite right to point out that you should have a split load board on a new install unless each circuit is protected by a RCBo (an idependent RCD/MCB combi device per circuit). But is this a competely new install? the reason I ask this is a 6 way board is not so common these days so i'm wondering if you have had new wiring to an old board, the other thing that makes me wonder this is because you use the term RCB, that may be an error on your part but RCB & RCCB were both abbreviations used by makers in the past for what we now commonly call an RCD, or perhaps you mean RCBo, pictures would really help.
NE fault is likely the cause and plastering can do that, take off any fittings you have plastered near, make sure there is no plaster in the boxes and that no wires are shorting to earth and that the earth cores are sleeved their full length with green and yellow sleeve
NE fault is likely the cause and plastering can do that, take off any fittings you have plastered near, make sure there is no plaster in the boxes and that no wires are shorting to earth and that the earth cores are sleeved their full length with green and yellow sleeve
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That is not what it says what it does say is:-
314.1 Every installation shall be divided into circuits, as necessary, to:
(iv) reduce the possibility of unwanted tripping of RCDs due to excessive protective conductor currents produced by equipment in normal operation.
With a small flat or caravan it is likely one RCD even at 30ma and 40ms will not trip unless there is a fault.
543.7.1.1 limits the leakage to 3.5ma on any one socket assuming no fault so with premises with less than 10 sockets it would be reasonable to expect that it will not trip unless there is a fault.
We have and I include myself worked to general rules which we have formed to ensure we comply with the regulations and for ourselves these work but it is so easy when looking at some one else's work to try to apply the same rules without checking exactly what other things they have done different to oneself. For example looked at a lovely Grade 2 listed building where all the cables were mineral insulated which meant there was no need for 30ma RCD protection on many circuits although of course 300ma type S were used for fire protection.
If questions were asked on here I am sure many of us would have given wrong answers especially on use of 1.5mm cable on a ring main.
T
tonyelectric
You make some fair comments eric, and yes certainly 1.5mm pyro is good for rings (rated 21A).
There may in fairness to the OP and his spark be a very good reason for such a small board, we could be talking a small terraced house or flat.
My own house is a four bed with its original Wylex 6 way board of which 4 are used (Ring, Lights up, Lights down, immersion) and is all governed by one 30mA RCD. Being that both me and the wife are electricians we really should have updated it!!!, saying that it never trips (and yes the RCD is goo and no I havn't bypassed it
)
To the OP, take a pic of the consumer unit, with its cover off if you can and more info on the size of the property.
There may in fairness to the OP and his spark be a very good reason for such a small board, we could be talking a small terraced house or flat.
My own house is a four bed with its original Wylex 6 way board of which 4 are used (Ring, Lights up, Lights down, immersion) and is all governed by one 30mA RCD. Being that both me and the wife are electricians we really should have updated it!!!, saying that it never trips (and yes the RCD is goo and no I havn't bypassed it
)To the OP, take a pic of the consumer unit, with its cover off if you can and more info on the size of the property.
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I have agreed to inspect and test an installation that was being done in an extension and it was under LABC so I was using the three signatures version of the installation certificate and I was popping around to advise where cables we routed. Because it took over 6 months I did go on holiday and I did get text messages and to answer was not really appropriate. It was not a forum who helped but my son who is also a commercial electrician who also had 2391. So I can see that A - D all could be true.
I have also planned to do loads of work before my accident in 2004 and now I am getting better will likely start doing it. Show me where the rules say I need to inform the LABC?
314.1 Every installation shall be divided into circuits, as necessary, to:
(i) avoid hazards and minimise inconvenience in the event of a fault
(ii) facilitate safe inspection, testing and maintenance...
(iii) take account of danger that may arise from the failure of a single circuit such as a lighting circuit
.
.
.
314.2 Separate circuits shall be provided for parts of the installation which need to be separately controlled, in such a way that those circuits are not affected by the failure of other circuits, and due account shall be taken of the consequences of the operation of any single protective device.
There really is no way that a competent electrician could believe that a CU with a single RCD that will take out the entire house if there's a fault on one circuit would comply with the regulations.
There just isn't.
How did you find this "great guy"? What makes him great, as clearly it isn't the quality of his work?
Was he recommended?
Is he registered with one of the competent person schemes?
Also:
That's a bit confusing - are you trying to tell us that the landing light gets it's live from the downstairs circuit and it's neutral from the upstairs one?
If so, that's another definite contravention:
314.4 Where an installation comprises more than one final circuit, each final circuit shall be connected to a separate way in a distribution board. The wiring of each final circuit shall be electrically separate from that of every other final circuit, so as to prevent the indirect energizing of a final circuit intended to be isolated.
See //www.diynot.com/wiki/electrics:sneutral
Your personal experience is showing you why it isn't right.
A single fault takes out your entire installation - all the sockets, all the lights etc, and even when it's found and fixed exactly the same thing will happen with any other fault in the installation, or with any faulty appliance in the future.
It would be interesting to see photos of what the guy did, but that might take you a while to organise, however in the meantime you could answer these straight away.
- Is the guy who did this work actually a qualified electrician?
- Is he registered with one of the Competent Person schemes - i.e. NICEIC, NAPIT, ECA etc?
- Has he actually given you an EIC?
- Has he notified the work to your local council's Building Control department?
Indeed - 6 circuits may be perfectly adequate, a 2-3 bed house with no shower circuit and no outbuildings could easily be done with 6 circuits.
But it's not the number of circuits at issue - it's the use of a single RCD so that one flaky appliance will take the entire house out.
6 RCBOs and 1 main switch would be fine. 6 MCBs and 1 RCD is not.
MK make an 8-module enclosure.
T
tonyelectric
I would say on a very small install you can get away with one RCD (not that I would personally do that but here is my rationale)
1 bed flat with 6 way board, circuits lets say RING, SHOWER, COOKER, LIGHTS, SPARE. There is a maintained fitting on the landing near the fusebox, agreed this is not a great set up as a fault on any given circuit knocks the others out, the maintained light will take care of hazards, ie fumbling in the dark to reset so the regs have been complied with.
However we are obviously talking of a house as the OP mentions upstairs and this borrowed neutral/earth scenario so IMHO a single RCD is not sufficient, I would have gone the RCBo route out of personal preference, but we need more info, photos yes and the answers to BAS's points would help too.
If the spark is registered we can take it as read he's qualified and done notification.
1 bed flat with 6 way board, circuits lets say RING, SHOWER, COOKER, LIGHTS, SPARE. There is a maintained fitting on the landing near the fusebox, agreed this is not a great set up as a fault on any given circuit knocks the others out, the maintained light will take care of hazards, ie fumbling in the dark to reset so the regs have been complied with.
However we are obviously talking of a house as the OP mentions upstairs and this borrowed neutral/earth scenario so IMHO a single RCD is not sufficient, I would have gone the RCBo route out of personal preference, but we need more info, photos yes and the answers to BAS's points would help too.
If the spark is registered we can take it as read he's qualified and done notification.
Depends on how wide & loose your definition of "qualified" is....
T
tonyelectric
Well he"s done at least 5 days worth of training
4, actually, plus ½-day practical test and ½-day multiple-guess theory test.
Wow guys, lots of info here obviously I used the wrong forum the first time round, let me have a look at your replies and I'll answer any questions. I'll post a pic of the cu too I think it is 100ma[/img]
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