Sub Main Supply

[electric will]

I don't think the op will dare do anything now after seeing what's gone on in here.

 

[MDJ]

Hi Will I hope that not the case, there have been several comments about checking the trunking for continuity and my view about running a seperate earth, I hope he can make his own mind up regardless of the negative posts on here not caused by myself I would like to add.

 

[Knobhead]

Considering when the thead started the mains will be in and live by now! I would hope.

 

[electric will]

I'm sure he will, I don't do any large industrial work as far as I go is working on old farms (where you'd definitely run a cpc) and the small workshop stuff, how ever it's been interesting to sit back and see the opinions from you and en54

 

[MDJ]

wouldn't the thread have been better if the "engineer" had not posted an insult? anyhow all done, I'm sure he will try again, bullies do.

 

[Billythekid]

Considering when the thead started the mains will be in and live by now! I would hope.

Pardon my stupidity Tony, how do you see when a thread is started?
New to forum . . . i've just been clicking the "What's New?" tab, is this not the way to navigate the forum?

 

[Bobster]

Pardon my stupidity Tony, how do you see when a thread is started?
New to forum . . . i've just been clicking the "What's New?" tab, is this not the way to navigate the forum?

Just above the name of the poster shows when it was posted.

 

[Billythekid]

Just above the name of the poster shows when it was posted.

More haste, less speed . . . . . hangs head in shame! :dozey:

 

[the oracle]

Afraid I am going to get a splinter in my backside, because I am sitting on the fence on this issue! Had a very similar discussion only a day or so ago. Bottom line is, yes, it is acceptable to rely on a properly installed and connected steel trunking system for all cpc's of all circuits. All earth links must be properly fitted, cpc's run to earth terminal of every accessory (socket outlets, switch plates, luminaires etc),and it must be tested thoroughly and achieve results that conform to BS 7671:2008 (2011). The cpc's must be terminated onto the trunking and bolted through effectively etc etc. But I am also aware that many installers prefer to instal separate cpc's, for the added security that they feel a separate cpc offers, should, for any reason the containment system fail. There is of course extra cost but that is their choice. In reality it matters not, the requirements of the Regs. are fulfilled and everyone is happy. I have installed in both ways, mainly the latter in recent years as architects/Q.S's etc have specified it, for reasons of their own, hence I feel the custom has become widely adopted (but NOT necessary). And if it means extra cabling and bigger trunking (and conduit) etc, well good luck with the price if you are tendering against someone who is not installing additional cpc's.

 

[Engineer54]

wouldn't the thread have been better if the "engineer" had not posted an insult? anyhow all done, I'm sure he will try again, bullies do.

Your a bit of a sad bugger on the side aren't you..

Bully, ...haha!! I don't think you even know the meaning of the word!!
If you consider what i originally posted as an insult, that's completely up to you. Shouldn't make statements that you'd expect from an electrician that has a fraction of your 29 years experience.

How have you survived for 29 years on site? Never known anyone as touchy as you.

 

[MDJ]

look it is not a matter of touchy, I told the OP I would recommend adding an earth wire to the new distribution board and recommend he does, it is my view, instead of you saying you wouldn't and you think the trunking would be adequate you decided to try to mock me publicly, now I have stood up to you, you are scrambling for cover trying to further discredit me by saying I am lying about engineers recommended earth wires in sub main supplies and that you don't believe I have been an electrician for a long period of time, I didn't start this argument, what should have been a discussion is ending with you trying to still gain something from a negative post you posted here on the forum, due to your post count and reputation you thought you could mock someone rather than discuss a job with them, I won't put up with it and I am standing up for myself and any other newcommers here against the sort of cyber bullying you think you can carry out, I still won't change my view about running an earth in with a sub main regardless of your post count and aggressive posting, if you wanted a proper discussion you may have got one and not the situation we are in now due to your negligence and not mine.

 

[johnboy6083]

All earth links must be properly fitted, cpc's run to earth terminal of every accessory (socket outlets, switch plates, luminaires etc),

Read more: http://www.electriciansforums.net/c...al/62184-sub-main-supply-4.html#ixzz28do7IFAi

Nowthe earth links are another bug bear of mine. I dont understand what their function is. Im talking about when you already have what i would call joiners, which are usually slightly smaller than the trunking, and fit inside. You then bolt though. Tray joiners are either wrap around or sit on the inside of the lip.

My point is, the copper link does not improve the conductivity of the joint. By bolting a joiner through the tray, ladder, trunking ect, you have already given a fantastic path for possible fault currents. I cant see why we are usually made to go and fit earth straps/links across them.
I only use links on fresh air joins, i jumping from one tray run to another.

 

[Engineer54]

I'm sure he will, I don't do any large industrial work as far as I go is working on old farms (where you'd definitely run a cpc) and the small workshop stuff, how ever it's been interesting to sit back and see the opinions from you and en54

If the metal containment system is corroding away due to the adverse environment it has been installed in, then yes i would agree with you. But in all honesty, if the installation was in that kind of state/condition, the installation should be replaced anway.

A metal containment system designed and installed to meet the environment it's installed in, will never require separate CPC's being pulled in to supplement metal to metal continuity!! It didn't need it 50/60+ years ago and nothing has changed to change anything since... The metal containment will out perform separate CPC's every time...

Afraid I am going to get a splinter in my backside, because I am sitting on the fence on this issue! Had a very similar discussion only a day or so ago. Bottom line is, yes, it is acceptable to rely on a properly installed and connected steel trunking system for all cpc's of all circuits. All earth links must be properly fitted, cpc's run to earth terminal of every accessory (socket outlets, switch plates, luminaires etc),and it must be tested thoroughly and achieve results that conform to BS 7671:2008 (2011). The cpc's must be terminated onto the trunking and bolted through effectively etc etc. But I am also aware that many installers prefer to instal separate cpc's, for the added security that they feel a separate cpc offers, should, for any reason the containment system fail. There is of course extra cost but that is their choice. In reality it matters not, the requirements of the Regs. are fulfilled and everyone is happy. I have installed in both ways, mainly the latter in recent years as architects/Q.S's etc have specified it, for reasons of their own, hence I feel the custom has become widely adopted (but NOT necessary). And if it means extra cabling and bigger trunking (and conduit) etc, well good luck with the price if you are tendering against someone who is not installing additional cpc's.

All i can say is that these Architects (they will be employing an electrical consultancy company) and Q/S's must be getting younger or getting some very suspect advice from somewhere or other. Either that or they don't trust the standard of workmanship from modern day UK electricians. Otherwise it's a complete nonsense, with absolutely no gain to be had anywhere, just a wad of money thrown away...

 

[cogsey133]

Sorry E54 while i agree with what your saying i also know what the oracle says is true. The architects do specify running separate cpc's on some of the jobs i have worked on. I even had one specify i had to bond over the pipe couplers on an air system because the pipe fitters had used ptfe tape at this point. It seems the architects think up some things and they must be obeyed.

So i also have nearly 29 years in this game and have had to use containment as the cpc but have also had to run separate (hope the fence is big enough for me and oracle)

 

[Engineer54]

Nowthe earth links are another bug bear of mine. I dont understand what their function is. Im talking about when you already have what i would call joiners, which are usually slightly smaller than the trunking, and fit inside. You then bolt though. Tray joiners are either wrap around or sit on the inside of the lip.

My point is, the copper link does not improve the conductivity of the joint. By bolting a joiner through the tray, ladder, trunking ect, you have already given a fantastic path for possible fault currents. I cant see why we are usually made to go and fit earth straps/links across them.
I only use links on fresh air joins, i jumping from one tray run to another.

I can see where your coming from, we actually use two copper links on all our trunking, tray, ladders, baskets etc. When i first come into the industry there was no call for copper links, but our company Plant Engineer at the time, (an American i might add) insisted on copper conductor links on all the above. So it must be an American thing to do too ... lol!!!