Dual earth terminals for computer circuits

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Discuss Dual earth terminals for computer circuits in the Australia area at ElectriciansForums.net

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brizospark

Noticed this on the architects notes can someone elaborate for me? thanks

the contractor should note the need for dual earth terminal blocks to be provided within DBs supplying computer power
 
IT equipment have high earth leakage currents so need 'High Integrity Earthing', the cpc should be connected to separate terminals on each socket on such a circuit and if it's a radial circuit a cpc should be taken from the last socket back to the DB.
Have a read of this...
http://electrical.------.org/wiring-matters/26/5437-earthing.cfm?type=pdf
 
I believe the type of earthing circuit depends on how high the total earth leakage current from the computers is.I am doing two rows of 4 and one of 2 at the moment,radials and each row has its own RCD.I will check the leakage current but I expect it to be very low.
 
telectrix said:
if you ain't come across it before, you won't know. i know a few sparks who are " old school" had never heard of high integrity earthing till recently.
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Well they should have because it is not "that" new, if they want to be classed as professionals then they must act as such.
Sorry my opinion stands, if the OP does not know then back off and get someone who does.
 
netblindpaul said:
Well they should have because it is not "that" new, if they want to be classed as professionals then they must act as such.
Sorry my opinion stands, if the OP does not know then back off and get someone who does.
Click to expand...
I thought the idea of this forum was to gain advice for things you are not sure about....the rudeness of some posters on here is breathtaking...........
 
I've just done a PIR on a large home office that had 10 PCs in and on day of test there was 27mA of earth leakage on the dedicated RCD circuit for those PCs (therefore approx 3mA per PC). Client reported occasional trips. Solution is another RCD as above. Thank heavens for the ramp test!
 
GLENNSPARK said:
I thought the idea of this forum was to gain advice for things you are not sure about....the rudeness of some posters on here is breathtaking...........
Click to expand...


I did my apprenticeship in the sixties in maintenance and at the time "I knew it all"or so I thought
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I found during my career,mainly installation, that others knew things I had no idea of
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Conversely,they were blind to subjects I thought were fairly routine
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You see where this is going to
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The only thing I will say is this,
Electrical work is a vast area, and one that luckily is covered by someone or other on this forum
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Reciprocating your knowledge is what the forum has been, and I hope will continue to be
Some give of their knowledge freely.others not so perhaps,but where would the forum be, without all of us lacking something or other to acquire
 
Des 56 said:
I did my apprenticeship in the sixties in maintenance and at the time "I knew it all"or so I thought
icon7.png
icon13.png


I found during my career,mainly installation, that others knew things I had no idea of
icon9.png

Conversely,they were blind to subjects I thought were fairly routine
icon14.png
icon7.png

You see where this is going to
icon12.png
icon4.png


The only thing I will say is this,
Electrical work is a vast area, and one that luckily is covered by someone or other on this forum
icon14.png


Reciprocating your knowledge is what the forum has been, and I hope will continue to be
Some give of their knowledge freely.others not so perhaps,but where would the forum be, without all of us lacking something or other to acquire
Click to expand...
THATS THE SPIRIT DES!....Most posters on here are out to offer advice and guidance whilst gaining some themselves. I look at it like this...if it wasn`t for institutions like this forum you`d end up with loads of installs "going wrong" at some point or another: We need someware to share advice and have a laugh whilst doing so...we`d all go mad if we didn`t..lol..:grinningelf:
 
jaresquire said:
Stick me in front of large motor control gear and I'd have to go into BS mode and I don't mean 7671!
Click to expand...

Stick me in front of a modern CU and I look confused, give me the MCC anytime. Don’t get me wrong I’d soon suss it out but it’s foreign territory to me!

Until I came on to this board I didn’t even know a MCBO existed.
 
netblindpaul said:
Well they should have because it is not "that" new, if they want to be classed as professionals then they must act as such.
Sorry my opinion stands, if the OP does not know then back off and get someone who does.
Click to expand...

In which case dont bother replying to the thread - your comments are neither useful or wanted
 
i did 16th in 1995 and no mention was made of hi integrity earthing then. it was only in 1998 when working in factory offices that i came across it, and that was after 25 years in the trade. as i said before, if you ain't met it, you don't know.
 
brizospark said:
Noticed this on the architects notes can someone elaborate for me? thanks

the contractor should note the need for dual earth terminal blocks to be provided within DBs supplying computer power
Click to expand...

People have assumed (as I did at first) that this is referring to high integrity (HI) earthing.

Just dawned on me, it could also mean they want clean and dirty earth bars, and possibly (HI) earthing.

I would seek clarification, because getting this wrong could be very expensive.
 
Yes indeed double check that they do not require clean earth, but i would have said, architect would/should have stated that they require clean earth (not a small detail) on circuit(s), but then again he/she could of over looked.
 
oxocube said:
People have assumed (as I did at first) that this is referring to high integrity (HI) earthing.

Just dawned on me, it could also mean they want clean and dirty earth bars, and possibly (HI) earthing.

I would seek clarification, because getting this wrong could be very expensive.
Click to expand...


Just read this thread from the beginning, and that was my first assumption, a clean and a standard earth bar. After reading the numerous post replies, i thought that i was mistaken, and had misread the OP's post. ...lol!!
 
Simlec said:
Yes indeed double check that they do not require clean earth, but i would have said, architect would/should have stated that they require clean earth (not a small detail) on circuit(s), but then again he/she could of over looked.
Click to expand...

This would be quite easy to determine, ..by checking drawings, ...Clean earths requirements are always quite clearly marked on main and sub-main distribution DBs and Panel drawings...
 
The op asks about dual earthing in the db, not at the sockets, the socket being where I thought the HI earthing had to be dealt with. Have I missed something or is the architect asking for something above and beyond BS7671?
 
The OP doesn't know what the requirement is, and why he posted his query. Which is also why he has been told to seek clarification as to what the specification note is referring too ....clean and standard earth bars or HI dual earth bars!!
 
glennspark i totally agree with your comments this forum is becoming worse with the comments of some sparks. if every spark knew everything we wouldnt need forums like this. even i am wary to ask a question incase some high almighty spark who thinks he knows everything may think that it is a dumb question to ask and then jump on the band wagon with there totally ignorant and demoralising comments, it is better to give a spark the right answer to his query than to let them think what they are doing is right and then find themselves in jail or worse die. yes in the real world it does happen to qualified sparks they do go to jail or die due to electrocution and hopefully this forum may stop even one spark from either spending time in a cell or 6 feet under, a spark cant even say he has had an electric shock because he would be afraid incase somebody told him he should have followed safe isolation procedures, i guarantee that the idiots who call themselves sparks who dont want to help other sparks work for a large company and often need advice themselves and can always call on their work mates to help them unfortunately there is a lot of us out there who dont have this luxury as we are on our own and so have to ask a question on here to hopefully get the right answer and not a load of belittling crap about the competance of that person being a spark. i dont even have to say who you are as a lot of the sparks reading this will already know who you are as they have probably experienced your comments also. stop acting like ****** to those who need your help as this should make you feel more proud to have given a spark some good sound advice. if i told you i farted next to a gas appliance you would probably say i wasnt a proper spark as it would be against regulations!!.
 
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What I cannot understand is why a so called competent and professional electrician cannot fathom something that came into the regs over 20 years ago.
The ONLY thing that COULD be of question is the clarification between hi integrity & clean earthing.
However, a competent professional electrician should be able to fathom this themselves, as it is quite straight forward stuff really.

I really worry these days about the competence of some "so called" electricians who are working in the real world and seem to have a very poor grasp of what are basic and fundamental principles and rules of the trade when they propose themselves to be professionals!

A professional has to undergo continuous professional development to retain their professional status, that means investment in themselves in training and in reference materials such as the relevant reference material such as standards.

I cannot fathom the depth of complaints that are forthcoming with regard to the reluctance to undertake continuous professional development, and, all that this entails, whilst shouting that electricians are professionals.

It beggars belief!
 
netblindpaul said:
I cannot fathom the depth of complaints that are forthcoming with regard to the reluctance to undertake continuous professional development It beggars belief!
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and i cant fathom why some people need to belittle some members for asking a question, this really shouldnt be the case on a open forum otherwise whats the point, yes some questions are very basic in their nature but surely expanding on them would be a better soloution even to the more experienced and intelligent of us?

i will also add that i have very little knowledge of the topic in question but ill make sure i dont ask for a fuller explanation .......
 
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That depends very much on what you determine a professional electrician is!! The problem today is, that the basic skills are not being taught to say the level you i and other older electricians were. The days of indentured Apprenticeships are virtually over, now it's down to these so called trade schools that promise the earth and deliver almost nothing. It's that, or local collages that don't have the funds to cover the full spectrum of our industry. They are both basically getting these students to pass the basic exams, and many are failing to do even that!! Most of these guys are passing out of these new style institutions with absolutely no working experience whatsoever!!


Most new electricians are now at most domestic installers, that would be totally lost outside of that environment. The younger ones may go on to improve themselves, (there are a few here on the forum) but many of the older guys that have retrained at a late stage in their lives, will be quite happy remaining firmly entrenched in the domestic side of the industry. So although i agree with you, it's sad to say that the professional side of things is sliding in a downwards direction too. I don't particularly blame these guys either, i blame the dammed system and the bureaucrats that has allowed our industry to slide to the level it is at now, and may not have reached it's bottom yet!! There is little enthusiasm to improve oneself, when these courses cost more than a normal family can realistically afford, and with little financial benefit at the end to look forward too....
 
What I can't fathom is the threads and comments on the forum berating companies for trying to operate in a financially sound manner, by down grading certain so called "electricians" who are not really and thus paying them less than others.
Then members actively support what appear to be unskilled or unqualified and incompetent persons to take their work away from them?
This is something that I find really difficult to grasp.

If the question had been asked from a learning point of view, for example:
"I am in college and we have been given this scenario" then I whole heartedly agree with supporting the OP.
However, when the OP appears to be taking work away from those of you who are competent and you are helping him to do it, where is the sense in that?
Work is difficult enough to get at the moment without giving it away to those who are not really competent to do it by training them to take your mortgage payments and the money to feed your kids away from you.
 
ezzzekiel said:
and i cant fathom why some people need to belittle some members for asking a question, this really shouldnt be the case on a open forum otherwise whats the point, yes some questions are very basic in their nature but surely expanding on them would be a better soloution even to the more experienced and intelligent of us?

i will also add that i have very little knowledge of the topic in question but ill make sure i dont ask for a fuller explanation .......
Click to expand...

The thing is, we all have our off day's!!! Sometimes it can get real hard not to make a comment on some of the posts that are written here. On one day, you may reply to the basic question being asked, or you may ignore it completely and on that off day reply with a remark!! lol!!!


One does have to wonder, at some of the queries made on the forum by working electricians, as to what level they have been taught this trade. You can understand when these questions have been raised by students and trainees, it's a different matter when it's an electrician asking the question.


As for this particular query, i wouldn't have said that it was a situation that many domestic installers would probably come across too often, if at all in their line of work, so i'm going to put Paul's remark down to him having an off day!! ...lol!!
He is normally quite free with his advise on replies to posts, and a knowledgeable poster on the Regs, as well as other statutory bodies that are involved in our industry...
 
netblindpaul said:
What I cannot understand is why a so called competent and professional electrician cannot fathom something that came into the regs over 20 years ago.
The ONLY thing that COULD be of question is the clarification between hi integrity & clean earthing.
However, a competent professional electrician should be able to fathom this themselves, as it is quite straight forward stuff really.

I really worry these days about the competence of some "so called" electricians who are working in the real world and seem to have a very poor grasp of what are basic and fundamental principles and rules of the trade when they propose themselves to be professionals!

A professional has to undergo continuous professional development to retain their professional status, that means investment in themselves in training and in reference materials such as the relevant reference material such as standards.

I cannot fathom the depth of complaints that are forthcoming with regard to the reluctance to undertake continuous professional development, and, all that this entails, whilst shouting that electricians are professionals.

It beggars belief!
Click to expand...
I wasn`t questioning your integrity..or your knowledge....rather the rude way you chose to post...thats all.....I will look forward to listening/learning from you (and others on here) in future.
with thanks.
Glenn.
 
solar power has also been around for quite a few years, but i would never call myself competent in that field. i understand the principles, but that is all. that doesn't make me incompetent in other fields. as engineer54 says, today's training leaves a lot to be desired and the younger sparks are chucked in at the deep end having learned all they have been taught but without practical experience and a "mentor" to guide them and explain areas in which they have little or no knowledge. we now have electricians who may be able to recite the regulations but give them some tray or steel conduit and they're lost. conversely, a guy may be an expert at cabling and terminating , yet know bugger all about testing or fault finding. to anyone contemplating training, i'd say be a chippy or a plumber.
 
Engineer54 said:
That depends very much on what you determine a professional electrician is!! The problem today is, that the basic skills are not being taught to say the level you i and other older electricians were. The days of indentured Apprenticeships are virtually over, now it's down to these so called trade schools that promise the earth and deliver almost nothing. It's that, or local collages that don't have the funds to cover the full spectrum of our industry. They are both basically getting these students to pass the basic exams, and many are failing to do even that!! Most of these guys are passing out of these new style institutions with absolutely no working experience whatsoever!!


Most new electricians are now at most domestic installers, that would be totally lost outside of that environment. The younger ones may go on to improve themselves, (there are a few here on the forum) but many of the older guys that have retrained at a late stage in their lives, will be quite happy remaining firmly entrenched in the domestic side of the industry. So although i agree with you, it's sad to say that the professional side of things is sliding in a downwards direction too. I don't particularly blame these guys either, i blame the dammed system and the bureaucrats that has allowed our industry to slide to the level it is at now, and may not have reached it's bottom yet!! There is little enthusiasm to improve oneself, when these courses cost more than a normal family can realistically afford, and with little financial benefit at the end to look forward too....
Click to expand...

too right Engineer54, with my college it felt like i was on a production line.. knock em up and bang em straight out.. Take your money and run.

Because of this forum and the continued help and support i get from you guys my knowledge continues to grow more and more everyday.This forum has helped me through so much that if it didnt exist id be lost without it. its sad, but its true. I have done well at college I've studied hard. Harder than most. And unfortunetly im not as priviledged to be working alongside someone but it wont stop me from becomin like you guys. Which is where i aim to be in a few years.

And i can also see that the professional side of things is sliding in a downwards direction. Everyday people are coming out of these colleges the same way they went in.. I felt that way the day i finished college last year. However, it really does depend on the individual and on how bad they want to learn. If im not on here my head is stuck in a book or im out in the real world trying to earn a living. Ive had to go self employed so i can continue to learn.. Most jobs ive applied for out there wont even give you the time of day which is quite sad. And thats where I think this industry is kind of going wrong. Id love to work alongside somebody and from someone who can teach me. But no one wants to know me unless i have 2391.. i cant do the 2391 unless ive had experience and The last thing I want to be is a cowboy or be 6ft under. Without this forum id be either one of those. You guys are my mentors and i sincerely appreciate it.

And i also appreciate the negetive comments aswell. i dont take them personally but i consider it to be something constructive.

What i love about this industry is not only is it highly technical but also theres always room to improve. Always something new to learn. Theres always areas in which to expand and to grow.

thanks guys!
 
solar power has also been around for quite a few years, but i would never call myself competent in that field. i understand the principles, but that is all. that doesn't make me incompetent in other fields. as engineer54 says, today's training leaves a lot to be desired and the younger sparks are chucked in at the deep end having learned all they have been taught but without practical experience and a "mentor" to guide them and explain areas in which they have little or no knowledge. we now have electricians who may be able to recite the regulations but give them some tray or steel conduit and they're lost. conversely, a guy may be an expert at cabling and terminating , yet know bugger all about testing or fault finding
Click to expand...

This very true,

I have worked several times in the panel building industry (for global companies) building some well known projects. These can be highly complex, with motorised ACB's, PLC controlled switch boards, Intelligent motor centres and G59 protection relay circuits etc..etc..,

But this doesn't mean I understand them, yes I can read the drawings, yes I can run the cables, and yes I can terminate the connections, and can even spot "obvious mistakes" but I still don't 'really' know that much about it.
I have done some ductor testing, primary and secondary injection testing, flash and megger tests etc. without learning a massive amount (yes I kinow what the tests were for). as this was not what was required, there was no need to understand fully as these were built and tested under 'instruction'.
I did do a bit of fault finding which I did find interesting, and I did learn quite a bit about some control circuits and HI and clean earths etc., but this was down to MY own interest, because I wanted to know more, most of the lads I worked with showed no interest whatsoever.

I have also worked on maintenance, which was mainly just unit replacement,and some fault finding

This was the reason I became a DI, because it is much more interesting learning about problem solving and it gives me much more testing and fault finding experience , and to get away from being robbed off of the various agencies etc. and puts me in charge of my own destiny.

I would never talk down to anyone who does not understand something, it is IMO far better to ask something you are not sure about than to carry on regardless, possibly doing something at best wrong at worst fatal. None of us know it all, I would prefer to ask someone who knows what I need to know, and not just give me a 'cut and dried' solution, as this won't help me the next time I face a similar problem, what I need are the reasons why something is done a certain way, and how things are worked out, or at least a nudge in the right direction of where to find the information.

For the most part this forum does this very well, and is a wealth of information from some very clever and very experienced people who provide knowledge that you will not get from any college course.

Cheers,
to All who contribute
 
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spark 68 said:
This very true,

I have worked several times in the panel building industry (for global companies) building some well known projects. These can be highly complex, with motorised ACB's, PLC controlled switch boards, Intelligent motor centres and G59 protection relay circuits etc..etc..,

But this doesn't mean I understand them, yes I can read the drawings, yes I can run the cables, and yes I can terminate the connections, and can even spot "obvious mistakes" but I still don't 'really' know that much about it.
I have done some ductor testing, primary and secondary injection testing, flash and megger tests etc. without learning a massive amount (yes I kinow what the tests were for). as this was not what was required, there was no need to understand fully as these were built and tested under 'instruction'.
I did do a bit of fault finding which I did find interesting, and I did learn quite a bit about some control circuits and HI and clean earths etc., but this was down to MY own interest, because I wanted to know more, most of the lads I worked with showed no interest whatsoever.

I have also worked on maintenance, which was mainly just unit replacement,and some fault finding

This was the reason I became a DI, because it is much more interesting learning about problem solving and it gives me much more testing and fault finding experience , and to get away from being robbed off of the various agencies etc. and puts me in charge of my own destiny.

I would never talk down to anyone who does not understand something, it is IMO far better to ask something you are not sure about than to carry on regardless, possibly doing something at best wrong at worst fatal. None of us know it all, I would prefer to ask someone who knows what I need to know, and not just give me a 'cut and dried' solution, as this won't help me the next time I face a similar problem, what I need are the reasons why something is done a certain way, and how things are worked out.

For the most part this forum does this very well, and is a wealth of information from some very clever and very experienced people who provide knowledge that you will not get from any college course.

Cheers,
to All who contribute
Click to expand...

I know what your saying here, but i would and do, find working on the more technical areas (such as mentioned in the first part of your post) far more interesting and rewarding and thus forefilling than working on domestic installations...

I can't for the life of me, see how domestic installation work is more interesting?? I can see however, that you would be in charge of your own destiny. But if you had taken a keen interest in the panel building, or more to the point, the testing and commissioning side of things, then you could have made a very lucrative career as a testing and commissioning technician on the bigger HV,MV,LV main switchboards and the like. Those guys can earn a fortune with the specialised companies, .....As well as seeing a good few countries in the process. So in a way you could have taken charge of your own destiny in a completely different direction!!!
 
And i also appreciate the negetive comments aswell. i dont take them personally but i consider it to be something constructive.
Click to expand...

As an arms member with nigh on 4 years membership I take comments like this very personally

Tony said:
After a comment like that your opinions are reduced like you to NOTHING
Click to expand...
 
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There will always be people of differing levels of knowledge and expertese which is where i beleive this forum comes into its own. The op has come accross something he is not sure about and has "dared" to ask for clarification on the matter. Surely thats to his credit.

Sometimes after reading particular issues in Bs 7671, and other relevent material, it is extremely helpful to read about it in normal language from highly experienced peope on this forum.

However when you see the mauling some op.s receive from certain individuals here, and they always seem to be the same individuals, just because they havent acheived the level of expertese and knowledge that "they" believe they should have,its dissapointng to say the least,

Surely insults and berating people is unhelpful and negative. If an op`s question is "upsetting" to some, all they have to do is ignore it and leave it to others to answer if they want.
 
A valid question is asked and within a few posts we are all dancing around the handbags again, alongside pulling the thread way off topic.

If anyone has anything helpful to add to the original question then please do, otherwise move on or start your own thread.
 
Well, I sent the op a pm advising him that dual earths could mean clean and dirty earths and/or HI earths because I realised my post and other relevant posts had got buried in all this off topic stuff.
 
oxocube said:
Well, I sent the op a pm advising him that dual earths could mean clean and dirty earths and/or HI earths because I realised my post and other relevant posts had got buried in all this off topic stuff.
Click to expand...

Nice one, OC.
Let us know his response, if he can be bothered after all this!
 
ezzzekiel, you insulted a respected member of this board. One who I look up to due to his experience in the law regarding industrial applications. I do fly off the handle now and again. But I think it was justified on this occasion.

You’re not backward when it comes to criticism!
 
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