Industrial earthing problems - again deadly

[Inteificio]

Hi,

As you might remember from the last thread, I'm now working in a factory where they used to contract out the electrics.
Unfortunately they used a negligent installer, so I have to fix it with no expenditure or time taken =-)

This problem is one of the main tank rooms.

There are a selection of stirring tanks, and a pump at the bottom.

The feed to each tank and pump is separate, with it's own isolator.

Each circuit has it's own overload.

Sounds alright so far, unfortunately:

There is no CPC to any of the tanks (SY sheath does not count in my books)
There is no equipotential bonding anywhere (this room is a high risk environment, it needs it!)

The only protection for short circuit or earth fault (apart from the overload which I assume will not trip in time) is a lone D50 breaker that covers everything.
All wired in 1.5mm (fun for a D50 breaker).

So my top priority is to make it safe, then legal.

I am putting in-line fuses for all to get the SC and EF protection, but the CPC problem is an issue.

I have read guidance note 8, regs and OSG and it is so vague.

If I had designed it each circuit would have it's own dedicated CPC, but pulling out all the SY and refitting would not be allowed, and strapping CPCs to the side of the SY has been managment vetoed too.

So my idea is to link the tank CPC to the Pump to allow it to carry the fault current. On the link I am also bonding it to a metal frame that goes to near the board and that is connected too.

The way I see it is any fault on the motor will dump current through the pump CPC and the parallel path through the steelwork (Steel CSA 40mm2).

This is a photo of what I have done (I'm sorry it looks so bad, we have damaged boxes and no budget to replace them or even get stuffing glands!)

 

[Inteificio]

So apart from the comments of 'that is so sloppy' Is there any advice that can be offered?

Is this the best way of doing it, is it legal?

 

[Engineer54]

Hi,

As you might remember from the last thread, I'm now working in a factory where they used to contract out the electrics.
Unfortunately they used a negligent installer, so I have to fix it with no expenditure or time taken =-)

This problem is one of the main tank rooms.

There are a selection of stirring tanks, and a pump at the bottom.

The feed to each tank and pump is separate, with it's own isolator.

Each circuit has it's own overload.

Sounds alright so far, unfortunately:

There is no CPC to any of the tanks (SY sheath does not count in my books)
There is no equipotential bonding anywhere (this room is a high risk environment, it needs it!)

The only protection for short circuit or earth fault (apart from the overload which I assume will not trip in time) is a lone D50 breaker that covers everything.
All wired in 1.5mm (fun for a D50 breaker).

So my top priority is to make it safe, then legal.

I am putting in-line fuses for all to get the SC and EF protection, but the CPC problem is an issue.

I have read guidance note 8, regs and OSG and it is so vague.

If I had designed it each circuit would have it's own dedicated CPC, but pulling out all the SY and refitting would not be allowed, and strapping CPCs to the side of the SY has been managment vetoed too.

So my idea is to link the tank CPC to the Pump to allow it to carry the fault current. On the link I am also bonding it to a metal frame that goes to near the board and that is connected too.

The way I see it is any fault on the motor will dump current through the pump CPC and the parallel path through the steelwork (Steel CSA 40mm2).

This is a photo of what I have done (I'm sorry it looks so bad, we have damaged boxes and no budget to replace them or even get stuffing glands!)

You know, i know, and everyone here knows (hopefully) that what your contemplating as remedial work isn't acceptable, and wouldn't comply with any standard that governs such industrial installations.

Doesn't matter what your employer might have to say or not say, they have statutory responsibility's to abide by, costs just don't come into this equation.... Any accident/fire or whatever and your companies insurance company will survey the installation as a whole, and in all likelihood remove any cover afforded by them due to electrical installation not meeting minimum standards and probably the HSE people will then be suing the ground from under your companies feet!! lol!! You wouldn't be fairing very well in that situation either, ...so be warned!!

If these poorly installed electrical installations have been installed by an outside electrical contractor, then your company should be making representations towards this company to rectify any work that doesn't meet minimum electrical safety standards/regulations

 

[Sharpend]

Why do 'we' always feel obliged to put everybody else's mistakes right? Then try and justify the shortcuts that we take to do it?
why not stand up and say this isn't right and to put it right is going to involve this. I dare say the management wouldn't have a monkey of an idea of what is right or wrong, so someone must have told them what Could be done to make it safe even if it technically isn't safe or right,why give them the option in the first place, it is inevitable that they will always choose the cheapest!
do it right or don't do it at all, anything less than right makes you a cowboy in my book.

 

[snowhead]

What are the tanks made of?
What is the pipework connected to them made of?
Are the pumps submersible / double insulated?

 

[Inteificio]

Thanks for the obvious remarks Sharp.

As it is, the company is aware the site is dangerous. I have done a full inspection, and filed a formal report.
They do not want me to fix it.

I am slowly repairing it when the boss isn't looking, but I am not paying out of my pocket for the parts.


As for this being against regs:
That was my question, I have read the regs and it does not seem in opposition (apart from stuffers).
It is not a standard install, but what exactly is the issue?

My understanding is that each circuit requires a designated CPC, and you are allowed to share this CPC.
I am using the CPC of an attached circuit.
In addition, I am providing a very good parallel path to help out.

 

[Inteificio]

Snow,

Everything is metal from the '60s.
There are two types of pipe. There are stainless jacketed pipes for pumping the products (and keeping it warm). Copper pipes feed the water to the jackets.
The electrical continuity of the stainless pipes is poor due to thin wall and lots of dirty screw fittings. The copper pipes are to be bonded as soon as the fittings arrive.

Pumps are external to the tank. Metal pipes connect tank to pumps and on

 

[Deleted member 72666]

I feel for you, but you must document your concerns and present them as a report on what you think is the minimum required to make things safe, then organise a meeting with the safety committee if you have one (sounds very much like you don't) or even the MD to discuss the report and get them to officially recognise the problems in writing (email is great for this) The minutes for these meetings are a great way of having documented proof of concerns being raised which will be your friend if the ***p hits the fan as the Duty Holders are dragged through the courts and as in most cases it'll be your word against theirs.

 

[Inteificio]

I think I must be phrasing my question poorly.

I have informed management, everything is documented. Their formal answer is NO.

What I am trying to do is make the above install safe but am unclear on regulations on non-standard earthing.

It is standard practice to have a separate CPC leading back to the main board for each circuit.
The regs however permit sharing of CPC (the only time I normally see this is with an earth tape running around a factory that all circuits use).

So what are the rules on this?

Once I have the fuses in, using the CPC of the adjacent circuit should be safe. Regs only require the fault path of a shared CPC to take the fault current of the worst circuit at once (not both).
That CPC can comfortably take the fault current, the supplementary bonding makes my earth return far in excess of requirements.

So what I am asking is:

1: Is this allowable, and if not, why not.
2: Are din rail fuses for each line the best approach for covering short circuit and earth fault? - Might think about a large RCD too.
3: Does anyone with relevant experience have any suggestion and advice on how to make the install better - taking in to account I am not allowed to pull new cables.

As for advice on how to deal with my company, although the concern is appreciated, i've got myself covered and have no budget or time allocated.

I'm only looking for advise on the technical side, and in that regard, I'd really appreciate anything you guys have to give. Someone must know more about this than me!

 

[Farmelectrics]

keep a copy of the report its your employers responsibilty to make the installation safe why are you even bothering putting it right

 

[Darkwood]

You shouldn't borrow a cpc off a dedicated final circuit but you can have a common cpc to multiple circuits i.e. a trunking system. Consider the circuit the cpc was borrowed from was disconnected it would make the other circuit a danger which is a situation you shouldn't have. Don't get confused with earth conductors for more than 1 circuit where often found in sub-mains supplies where the earth is affording protection of the several circuits connected to the sub mains.

 

[Sharpend]

Whilst I admire your commitment and enthusiasm, I would be very concerned about leaving myself open to being the fall guy should things go badly wrong.
If the management are not prepared to entertain your report then so be it on their head.

 

[KAS1]

Is it my eyes or I am correct in stating that the sy cables are not supported throughout their length (on the tray and also dangling from the isolators) ? also it looks like the IP rating of the isolators have been breached with the earth cable shoved through a blind grommet (top entry at that) are the locking mechanisms broken as well? Is that a cable laying across the floor? If you're going to leave that mess, run the cables in some galv trunking (use that as your cpc) lol better still rip it out and use swa, if they're paying your wages to be there anyway, its only the cost of some materials job done.

 

[Guest55]

so if your company doesnt want you to do the work......
or the client / site owner wont pay for the work anyway........
why the hell are you bothering with someone elses mess ?
sorry , really dont understand your objectives.

as for the issue of plant wired in 1.5 with no cpc all sharing a single D50....
forget it , the whole design needs re thinking.

 

[Engineer54]

I think I must be phrasing my question poorly.

I have informed management, everything is documented. Their formal answer is NO.

What I am trying to do is make the above install safe but am unclear on regulations on non-standard earthing.

It is standard practice to have a separate CPC leading back to the main board for each circuit.
The regs however permit sharing of CPC (the only time I normally see this is with an earth tape running around a factory that all circuits use).

So what are the rules on this?

Once I have the fuses in, using the CPC of the adjacent circuit should be safe. Regs only require the fault path of a shared CPC to take the fault current of the worst circuit at once (not both).
That CPC can comfortably take the fault current, the supplementary bonding makes my earth return far in excess of requirements.

So what I am asking is:

1: Is this allowable, and if not, why not.
2: Are din rail fuses for each line the best approach for covering short circuit and earth fault? - Might think about a large RCD too.
3: Does anyone with relevant experience have any suggestion and advice on how to make the install better - taking in to account I am not allowed to pull new cables.

As for advice on how to deal with my company, although the concern is appreciated, i've got myself covered and have no budget or time allocated.

I'm only looking for advise on the technical side, and in that regard, I'd really appreciate anything you guys have to give. Someone must know more about this than me!

''It is standard practice to have a separate CPC leading back to the main board for each circuit.''

Do you really need to ask this question?? Your talking about multicore cables are you not, so the answer is Yes!!

You don't borrow other final circuits CPC's, and you don't tap of the structure or add-hock steelwork for your CPC connection either!!

As has been already explained, an electrical metal containment system is not the same as add hock steelwork. Any earthing related to that metal containment system, is made/installed to be electrically continuous. In such cases no separate final circuit CPC's need to be run within such a system and any earth connection at points of termination, can be made directly to or via that electrical metal containment.

Your trying to find ways around the problems your encountering, looking for wording within BS7671 and OSG's. Unfortunately your not going to find any. The add hock steel work does not meet the same requirements as an electrical metal containment system, so don't use them to provide a CPC connection to non compliant cables.


As others have stated, this is now not your problem, you have made representations to the company about your concerns, it's now firmly in their court. You could actually be making things worse for yourself by conducting these alterations to the existing installations. So leave it alone and let your employer take the responsibility for their lack of action and interest, after all they are taking the profits!! lol!!

 

[GMES]

As others have stated; leave it alone please. I admire your conviction, but thats exactly what you could end up with.
Your bosses sound like they don't give a damn, so why should you!.
God forbid someone gets a fatal shock, or there is a fire and an investigation is launched ( which there will be ) then the 1st question asked will be, who was the last person to carry out any electrical work, this is you and from what i've read so far , your employers won't hesitate to give them your name. Please walk away from this problem.

 

[Inteificio]

As for why I am doing it, if someone gets an electric shock, then it will be one of my friends.
I am happy to sit in court and argue my case if someone gets hurt, if my actions reduce the risk of harm.

The D50 is just an embarrassment, whoever installed this **** should be ashamed.
Once it is fused it should disconnect in time, but be illegal.

As for containment. Yep cracked housing, compromised IP ratings (the hole is sealed), unsupported wires, no earths and water everywhere.
The place is a state.

I can't fix all of the above, but I can improve it.

As for this no longer being my problem, you are part right. Mass layoffs today, and I have a meeting with HR on Tue.

My moneys on this won't be a good week.

Thanks for the help guys.

 

[GMES]

Didn't mean to be rude or clever just don't want to see you get in trouble, over it.
hope your job is safe. Good luck with it all.

 

[Deleted member 72666]

Didn't mean to be rude or clever just don't want to see you get in trouble, over it.
hope your job is safe. Good luck with it all.

I hope it's safer than the electrics!

 

[Englishsparks]

Ok, since your not listening to what people are saying!

Leave it alone!

If anything happens your the last person to work on it,if you don't do the remedials 100% correctly then you will still have to brunt some of the blame.by putting something only 50% right you are taking the blame away from the original installer or the management and putting it fair and squarely on your shoulders 100%
I fully understand where you are coming from, but only correcting things partly is not the way forward.

Its all down to the good ole saying protectum rectum.

 

[Inteificio]

Eng the point is probably moot now, but do you really not understand my point?

It is not about covering my arse, it is about protecting lives. If someone gets hurt badly, and I did nothing, what kind of person would that make me?

 

[stuartcourt]

I see where you are coming from but if your bosses dont care how unsafe it is they will care nothing to hang you out to dry if you touch it. You have done your job now try to get a better job as these people do not deserve you

 

[brookster]

double post

 

[brookster]

I would connect all tanks ect earthing to main earth bar which is then fed to the main earth at the board. This is what we would do installing gen sets with fuel tanks, don't know how much help that is to your situation.
Obviously grading the main CPC correctly.

We would have all tanks, pipes, gennys all earthed to the change over panel them fed back to the main earth @ the main incomer.
If changeover was on the gen set we would put a main earth bar to connect all the different earths before it goes back to the main earth at supply.
Keeping everything at the same earth potential.

 

[Deleted member 72666]

Eng the point is probably moot now, but do you really not understand my point?

It is not about covering my arse, it's about protecting lives. If someone gets hurt badly, and I did nothing, what kind of person would that make me?

Embarrass your employers by having a 'whip round' and hopefully with the proceeds install RCD protection then at least you've made it safer than it was.

 

[Engineer54]

Originally Posted by Inteificio
Eng the point is probably moot now, but do you really not understand my point?

It is not about covering my arse, it's about protecting lives. If someone gets hurt badly, and I did nothing, what kind of person would that make me?

I think we all see what your trying to do,but their comes a point where you have to start thinking about your own family first. Putting yourself in a position where you become part of any investigation and possible partial blame awarded against you, will have an effect on them. Also, having any conviction of this sort against you, will/can be a killer trying to gain potential employment with any large institutional employer!!

 

[Darkwood]

Originally Posted by Inteificio
Eng the point is probably moot now, but do you really not understand my point?

It is not about covering my arse, it's about protecting lives. If someone gets hurt badly, and I did nothing, what kind of person would that make me?

I think we all see what your trying to do,but their comes a point where you have to start thinking about your own family first. Putting yourself in a position where you become part of any investigation and possible partial blame awarded against you, will have an effect on them. Also, having any conviction of this sort against you, will/can be a killer trying to gain potential employment with any large institutional employer!!

Ouch!!! but a reality check and 100% agree with you E54....its a knife edge he walks upon.

 

[markythesparky]

They do not want me to fix it.

Why do it then? If they don't want it done, don't touch it. If someone gets hurt after you've touched it, the company would have no problem pointing the finger at you. Leave it alone and then they will be liable.

I am slowly repairing it when the boss isn't looking, but I am not paying out of my pocket for the parts.

You won't have to if you don't touch it!


My understanding is that each circuit requires a designated CPC, and you are allowed to share this CPC.
I am using the CPC of an attached circuit.

If each circuit requires its own CPC (as per BS 7671) then how can you also share a CPC? Is it me?

I'm sorry but I am at a loss as to why you are getting involved in this. If the people holding the purse strings say NO and you continue to do work on it (and cut corners in doing so) then you only have yourself to blame.
You must be mad!

Unless there is another side to the story?!?!?

 

[Inteificio]

I read it that each circuit requires a designated CPC.
So each circuit must have a fixed path to earth.
I do not think that each designated earth path must be unique.
As in, if you have a factory earth tape, each circuit has a CPC to the earth tape, then the earth tape becomes the CPC for multiple circuits at once.

Unsurprisingly this CPC would need to be marked at every point that it is used by multiple circuits.

If this is not the case, why is there a reg that says shared CPCs need to be rated only for the largest circuit?

p.s, You would also share a CPC on a sub-main.

 

[Darkwood]

Don't let Markythesparky confuse you ... I don't know why he has put each circuit requires its 'OWN' cpc as this isn't the case If he's under that impression then maybe he can show the REG' where he gets this from, conduit, trunking, steel wire armouring in a sub main supply can all be part of an earth return for multiple circuits.... re-read my previous post ive explained clearly and also reasons why you cant borrow the cpc like you suggested from an adjacent final circuit.

 

[brookster]

Don't let Markythesparky confuse you ... I don't know why he has put each circuit requires its 'OWN' cpc as this isn't the case If he's under that impression then maybe he can show the REG' where he gets this from, conduit, trunking, steel wire armouring in a sub main supply can all be part of an earth return for multiple circuits.... re-read my previous post ive explained clearly and also reasons why you cant borrow the cpc like you suggested from an adjacent final circuit.

I certainly wouldn't use trunking as my earth return for a 500kva gen! They also don't allow armor (steel bit) to be used as a CPC anymore it has to be separate conductor (client based).

Run everything in the same size it has supplied to it to a big earth bar on the wall. Run the largest size +50% for earthing goodness from this bar to the main earth at the incoming DB - job done.
All your trunking and tray ect will be earthed from the main board or boards anyway.

 

[Darkwood]

I certainly wouldn't use trunking as my earth return for a 500kva gen! They also don't allow armor (steel bit) to be used as a CPC anymore it has to be separate conductor (client based).

With all due respect im replying regarding the OP's situe' and other than yourself there has been no mention of a Generator had this been the case then my advice would differ but as far as what ive put ill stand by my advice as its within the BS 7671

 

[brookster]

With all due respect im replying regarding the OP's situe' and other than yourself there has been no mention of a Generator had this been the case then my advice would differ but as far as what ive put ill stand by my advice as its within the BS 7671

I would still go separate CPC, every job I would run a separate CPC doesn't matter if its a light or a MVA gen.
What happens if one of your return trunking bends falls off the full system is kapoot?
They do get 'shared' though, just not using the mechanical protection of the install.

 

[Darkwood]

Im not nor have I ever said anything against the preferred method of having separate cpc's for each circuit, I was merely commenting on OP's confusion with the regs regarding cpc's been used for multiple circuits and using conduit, trunking etc always has been and is still a perfectly acceptable way to provide an earth and just because you practice other methods through preference doesn't mean its in anyway poor practice to use conduit or trunking as earth, im confused at your comment about the trunking bending or falling off ...you can say that about anything ...what if the earth terminal comes loose, or the earth breaks ....approaching the debate with that kind of thinking won't help the OP it will only lead to more confusion ....as I said im referring to the BS 7671 and if you do have a look it does stress that trucking, conduits etc should be mechanically sound so I cant see anyone having a problem if they decided to use it for earthing... to note though you cant just use anything metal as an earth path it has to meet criteria set in the regs.

 

[brman]

I'm going to stick my neck out a bit here and side (partially) with the op here.

I see darkwoods argument about the danger of borrowing a cpc from another circuit but I am struggling to find an actual regulation that says you can't. Plus I had exactly this problem with a domestic (class 1 lights without a cpc on the cct) where I was doing a CU change. I asked elecsa's helpline and got a clear answer - "yes you can borrow the cpc from another circuit as long as you make a note of it on the cert, after all you are just making it safer".

As long as you are making things safer (and safe to an acceptable level) and have documented what you have done and why then why not if it is all the customer/boss with accept? If you are worried about someone disconnecting the other circuit then stick a nice big label on the DB.

Having said all that, I do worry about doing the work without it being authorised by the management. That does leave you a bit open if the **** starts flying, especially if some pedant can show you have actually made things worse in some way (eg further compromised the IP rating etc).

 

[PEG]

Sympathies with the OP but maybe the company is having to make cuts due to the money they have wasted having inspections carried out only to ignore the findings...

 

[Engineer54]

I read it that each circuit requires a designated CPC.
So each circuit must have a fixed path to earth.
I do not think that each designated earth path must be unique.
As in, if you have a factory earth tape, each circuit has a CPC to the earth tape, then the earth tape becomes the CPC for multiple circuits at once.

Unsurprisingly this CPC would need to be marked at every point that it is used by multiple circuits.

If this is not the case, why is there a reg that says shared CPCs need to be rated only for the largest circuit?

p.s, You would also share a CPC on a sub-main.

I'm not going to get further involved in this argument, i've clearly made my veiws on this matter in earlier posts on this thread.


What i will say here, is that earthing tapes, around a factory wall are not provided as a means of supplying circuit CPC's, they are there as a supplementary means of bonding equipment and isolated extraneous metalwork and the like.

 

[vaughant]

Personally I'd phone HSE if I were the op as this sounds like a timebomb waiting to go off.

that way it MUST be fixed,I'm sure one of the directors can keep his 2 year old BMW M5 another year rather than changing it for new.