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- armour cpc electricians' talk swa
D
Deleted member 26818
Yes the SWA is a ferromagnetic enclosure. However there is apparently going to be an exception to the requirement for CPCs to be within the ferromagnetic enclosure for SWA in the first ammendment.
D
Deleted member 26818
There is a report about from the ERA, produced for the ECA, I believe it's entitled 'ECA appendix 16' or similar.
This has information on the use of a separate CPC with SWA.
This has information on the use of a separate CPC with SWA.
X
xXDeltaXx
Just a little addition in relation to a previous point...
People coming from a 'fast track' scheme may not have covered this in enough detail to know for certain if the SWA armour is suitable for an installation - I know that I am / was unsure - This thread has helped me
I'm not quite sure on the point about loosing business to someone fresh (inexperienced) into the industry...
I will just state that the reason I'm here and looking for this info is because my company (not electrical) has an old boiler installation (late 80s) which I believe to be unsafe / questionable methods have been used on installations / modifications. The company has had electicians into and around the area before and no-one has commented on the installation - thus it will remain unchecked until it goes wrong. By carrying out calculations and checks, I hope to be able to get things rectified...
This kind of topic may end up generating jobs for the more experienced electrician rather than taking them away.
People coming from a 'fast track' scheme may not have covered this in enough detail to know for certain if the SWA armour is suitable for an installation - I know that I am / was unsure - This thread has helped me
I'm not quite sure on the point about loosing business to someone fresh (inexperienced) into the industry...
I will just state that the reason I'm here and looking for this info is because my company (not electrical) has an old boiler installation (late 80s) which I believe to be unsafe / questionable methods have been used on installations / modifications. The company has had electicians into and around the area before and no-one has commented on the installation - thus it will remain unchecked until it goes wrong. By carrying out calculations and checks, I hope to be able to get things rectified...
This kind of topic may end up generating jobs for the more experienced electrician rather than taking them away.
A
andyemms
Well I have found all this a very interesting read... I for one would choose to use both the armouring and an extra core as a CPC.
I think it is important to remember that this forum attracts people from everyday walks of life. There are some very knowledgeable and experienced people on here, there are some very knowledgeable but inexperienced people on here and there are people that have very little knowledge or experience. But we are all here for a reason, either to share our knowledge, or to gain knowledge.
YEEE HAAAAAA!
I think it is important to remember that this forum attracts people from everyday walks of life. There are some very knowledgeable and experienced people on here, there are some very knowledgeable but inexperienced people on here and there are people that have very little knowledge or experience. But we are all here for a reason, either to share our knowledge, or to gain knowledge.
YEEE HAAAAAA!
B
biguner
Doesnt it depend on the csa and length of run as to whether or not it needs additional cpc?
Your answer is in post 1
T
tom1400l
yes, its supposed to be earthed (c.p.c) anyway, try and get terminate it so that you can get the lowest resistance you can get
M
mattd888
I have a similar table that the niceic sent me. Another point is that although the armouring is suitable for the circuits cpc it would be important to remember that it my not satisfy the requirements for bonding of water pipes etc if the armoured was a sub feed. Rotting of the armouring can be an issue but that is why a periodic inspection is/should be carried out to catch such issues before it completly breaks down.
B
BARK982
The armour of swa should always be connected to earth and that's why you don't have to rcd protect a swa because if you damage it you will hit an earth before a live conductor, thats why you don't see a lot of two core swa about because people stopped buying it and just using the old yellow or new black as the earth. But the cross sectional area of the swa is larger than the earth conductor inside the cable, but why not connect both.
J
johnny999
This is the reason why we were taught at collage not to use it!!
M
malcolmsanford
You have been taught in a college never to consider using the armoured of a SWA as the CPC?
E
Engineer54
The mind just has to boggle at some of these so called competent to teach Electrical lecturers these day's.
M
malcolmsanford
I know mate I sometimes just can't believe what is happening to our industry.
Not this young lads fault but the institution.
Apparently teaching someone to run a cat cable and terminating a RJ45 plug is considered more relevant to an electrician than running and terminating MICC.
J
johnny999
Sorry guys that was taught, it can corrode or come loose in the gland therefore not giving adequate continuity.
M
malcolmsanford
Johhny your quite right it can corrode in certain environments and of course it can come loose.
But IMO you should be taught all types of erection methods. I may very well feel as the designer that running an SWA in a ship yard or perhaps a chemical store will most likely have a corrosive affect on the armour. But if that was the case I would be looking at another method, perhaps galvanized trunking/conduit or even sheathed MICC, but if SWA was the best method then yes I would most likely run a 3 core using the 3rd core as your CPC.
As for the remark about it maybe coming loose well you could say that about any form of termination even the 3rd core of your SWA in a screw terminal.
I just feel that by blanketing use of "always using a 3rd core of a SWA as a CPC" is depriving you the student of designing an installation that is safe and the best for it intended use, as well in a lot of cases it's most cost effective.
But IMO you should be taught all types of erection methods. I may very well feel as the designer that running an SWA in a ship yard or perhaps a chemical store will most likely have a corrosive affect on the armour. But if that was the case I would be looking at another method, perhaps galvanized trunking/conduit or even sheathed MICC, but if SWA was the best method then yes I would most likely run a 3 core using the 3rd core as your CPC.
As for the remark about it maybe coming loose well you could say that about any form of termination even the 3rd core of your SWA in a screw terminal.
I just feel that by blanketing use of "always using a 3rd core of a SWA as a CPC" is depriving you the student of designing an installation that is safe and the best for it intended use, as well in a lot of cases it's most cost effective.
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J
johnny999
I think the course I was on ( 3yrs @ 1 day a week ) was symptomatic of the way this country has gone in the last few years, "keep it simple & go heavy on the Health & safety". I have lots of questions to ask which most of you will roll your eyes at.
G
Guest123
In a nutshell.
I am astonished that you have been taught in this fashion, rather than outlawing it due to possible deterioration, they should be showing you how to install it in order to protect against the problem.
I despair, I really do!!!!:mad2:
M
malcolmsanford
Don't be afraid Jonny to come on and ask questions son, the majority on here are more than willing to try and fill gaps left in your training.
as I said in my post to you, it's not your fault that your trained in this way, and a few of us older lags would have trained you properly, or at least shouted at you properly.............
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Engineer54
Malcolm,
It even seems that these so-called lecturers are teaching students to favour radial circuits over RFCs !!! It's not going to be long, if that continues, that the sparks of tomorrow will be gasping in despair at the thought of having to fault find a ring circuit let alone test one!!
I think the whole curriculum of student training, needs a good kick up the arse. Just wait and see all the lecturers on here now, come back defending all the modern virtues of the courses they run ... The fact is, at best all we are producing these days are poorly trained domestic installers. It's left to them, to gain the experience they need, to become a well rounded electrician
M
malcolmsanford
I think mate that is another of those nails hit firmly on the head there.
I have to say working overseas for a number of years I have gotten out of the RFC way of thinking, but I personally feel that in many cases it is a viable and a best option.
As you say the trouble with RFC is that it is much more complicated when designing it and testing it, than a bog standard radial. The rule of thumb methods of finding the cable Iz by multiplying the protection device by 0.67, working out Volt Drop and loading the ring, will as you say be a thing of the past, much the same way as MICC is.
I suspect your right tutors/training centres will say it is "development" and "modernizing" of the industry and I suppose it is, but for me still a shame.
E
Engineer54
Nothing to do with the IET, but it has everything to do with the lecturers and promoting their own prejudices especially when they are factually and/or fundamentally Wrong!!
We have one lecturer here, that has openly stated that he guides his students away from RFC when providing socket circuits!!! Probably also tells them they can't use a SWA armouring as a CPC too... If these so-called lecturers can't be constructive in the advice they give to there students, then best keep their ill founded opinions to themselves and not burden the students to perpetuate them
We have one lecturer here, that has openly stated that he guides his students away from RFC when providing socket circuits!!! Probably also tells them they can't use a SWA armouring as a CPC too... If these so-called lecturers can't be constructive in the advice they give to there students, then best keep their ill founded opinions to themselves and not burden the students to perpetuate them
Z
ZsElectric
I recently found an swa used in this way to a garage, personally in such a zone I would never try to use the sheathing and so installed a rod to earth the satellite box, maybe I dont like to cut corners but then I never take chances just for an easy life
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Engineer54
So you think a rod is better than a TN system earth do you?? .....Then your a fool !!!
The mind just has to boggle at some of the completly daft an ill informed statements such
as this one.
G
Guest123
Perhaps you'd care to elaborate on what corners are being cut & what chances are being taken by using the knowledge we glean over the years coupled with the training we received, to establish the suitability of a particular material for a particular application???
Not doing something because you 'dont like it' (or dont know any better), then claiming those that do are 'cutting corners' & 'taking chances' is nonsense frankly.
You'll also have to enlighten me on how an Ra of 100-200ohms (probably), is better than a Zs of around 0.5-0.7ohms......
E
Edd
In respect to the above posts,, I never take the earth from a property out to an external area, garage shed etc. even though as you say a good Zs from a TN system is a lot better than a high Zs on a TT.. the taking of one earth potential ( the house) to an external area such as the garage can cause (and I have seen it) a potential diffrence..
my main aim when wireing to out buildings is keeping any fault current/ voltage below 50v and appropreate disconection times. Ive seen lost neutrals on PME systems where outhouse neutrals and earths have become live to the surounding earth... would hate to step out that hot tub bare foot onto tera firma.. but hey thats me.. and I know this argument has been done to death, but ive seen the consequences of taking earths from diffrent areas and felt the potential diffrence!!!! :rolleyes4:
im not starting an argument... its just what i feel,, and as long as we are safe and follow the regs,, then we all win!!
my main aim when wireing to out buildings is keeping any fault current/ voltage below 50v and appropreate disconection times. Ive seen lost neutrals on PME systems where outhouse neutrals and earths have become live to the surounding earth... would hate to step out that hot tub bare foot onto tera firma.. but hey thats me.. and I know this argument has been done to death, but ive seen the consequences of taking earths from diffrent areas and felt the potential diffrence!!!! :rolleyes4:
im not starting an argument... its just what i feel,, and as long as we are safe and follow the regs,, then we all win!!
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E
Edd
yep too right,, but too date,, with my training and experience, ive never been able to predict the failing of a neutral on a pme system,, if i could i would be doing other things .. "joking please dont rip into me"
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Guest123
I never 'rip in' to anyone.:15:
I just get a bit wobbly when a blanket statement is made on a topic & the only reason being that someone doesn't like doing it the other way.
Obviously there are a number of situations where certain methods of doing things aren't appropriate, but to tar all with the same brush without any thought is a bit blind IMO.
This is almost turning into an extending pme thread (:wacko, we best leave it there I think.
I just get a bit wobbly when a blanket statement is made on a topic & the only reason being that someone doesn't like doing it the other way.
Obviously there are a number of situations where certain methods of doing things aren't appropriate, but to tar all with the same brush without any thought is a bit blind IMO.
This is almost turning into an extending pme thread (:wacko
, we best leave it there I think.OFFICIAL SPONSORS
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