VOELCB question pre regs change, but still in use.

[jackofall]

Good evening gents,
I am new here so will say thank you to anyone that takes the time to read this post, even if you don't reply to it.
I have been asked to look at an unusual vehicle based Mobile communications setup which uses a VOELCB for a chassis earth trip and a separate safety earth trip. This being the only main isolator.
Obviously if this was built today, it would not be up to current regulations as there is no main RCD protection, but I am being assured by the client that this was designed and built pre the regs change in 2008.
The power for the installation is supplied from an on-board generator to the skin of the vehicle which can supply up to 62A, so a fair amount of juice.
The question that I have is, if the chassis earth fails to trip, but the safety one still functions once the platform has been set up and earths applied, would the installation still be safe to use? The answer may seem simple, but am having to put up an argument over it.
Another question I have, if you are doing the yearly inspection how would you go about recording the performance of the VOELCB? R1,R2 tests can still be carried out within certain parts of the wiring, along with some trip times on RCDs within the vehicle that are supplying 13A plugs but just not sure on the main way of testing the isolation of the vehicle.
Any answers would be appreciated.

 

[alanl]

Voltage operated earth leakage breakers are / should be obsolete, and cannot be tested by the vast majority of people to ensure their functionality.
There used to be equipment for testing them, but I doubt anyone has one now, and if they do, I doubt it has been used / calibrated for many years.
Tell the client they should change it for a RCD. What would be the cost £50-75? Less than a tankful of fuel to ensure their safety.
As with all older equipment, you cannot require them to change it, but they should be made aware of the unit's failings (age, cannot test, not reliable etc), and it warrants at least a C2 on a EICR - is it a Work vehicle? If so, H&S at work, and EAWR will apply, so it should be changed.

 

[guest119]

Does the VOELCB have over current protection also or is that handled by the generator main switch/breaker?

Boydy

 

[jackofall]

Thanks for the reply's, this is quite a difficult one to explain. Although the equipment was designed pre regs change, it has only just started being used in the last year or so. Technically its new as its just been supplied, but was still built before 2008. (cop out I know).
Its not as simple as swapping out the VOELCB for RCD, as there is a lot of inherent earth leakage on the platform already, which should have been tackled at the design stage from filters, but there would be far too much cost implications to change it now, without causing a major fight between client and supplier of platforms. Its not just one platform, its multiples of the same.
I am not sure about the overcurrent on the gene, but I don't want to go down that route, as should the worst happen, you would not be able to fall back on that as a safety measure, so I have to tackle the actual VOELCB. The other thing I need to consider is that there is the possibility to use power from outside the platform, so therefore looking at the earth that could be supplied there.....But that still means I would need the Chassis earth to definitely trip.
The supplier is trying to tell me that if the Chassis earth does not trip, that its still safe to use the platform, So I am trying to get that in written form, as I cannot for one second see how that could be true. (equipment has been though extensive testing, but still not happy with that statement) as I believe it would be the most important part having the chassis earth trip.
If i go down the H&S at work route, that will be a massive bun fight and would make me as welcome as a wet fart in a space suit, so am finding it hard as to which way to turn. I am very aware that I cant afford to get this wrong, and I realise from reading other threads on here, that there are some very clever/experience sparks and engineers on here.
So for the yearly, do you just mark down that you cant test the overall I/P power safety? After all, that's one of the main reasons for the yearly.....

 

[Marvo]

If the application is power critical then get the customer to spend the extra money and go with a programmable earth leakage monitor. You can set it up to acommodate acceptable standing leakage and either activate an alarm that requires acknowledgement or to trip depending on how much and how fast the leakage current value rises. Can all the people who have access to the mobile installation be classed as electrically competent persons?

 

[jackofall]

If the application is power critical then get the customer to spend the extra money and go with a programmable earth leakage monitor. You can set it up to acommodate acceptable standing leakage and either activate an alarm that requires acknowledgement or to trip depending on how much and how fast the leakage current value rises. Can all the people who have access to the mobile installation be classed as electrically competent persons?

Had this sort of set up on power vaults before, which worked well, but would not work in this case. As they are not competent persons, not even close, which is why I am banging the safety drum.

 

[Marvo]

I'm not very familiar with the UK regs but I had a feeling there was a 'competent person' clause somewhere that might have given you some more room for maneuver when it comes to RCD requirements.

Do these mobile units definitely fall under the scope of the normal installation regs? Do they come under the caravan regulations or maybe are they military etc?

 

[spark 68]

The thing is, VOELCB have not been used since about circa 1981 !, so it is not just pre-17th edition, but almost pre- or about 15th edition !

My 15th edition regs (first of this edition dated 1981) still has the test procedure in it for these, ie injecting a 45volt AC voltage across N and Earth.

Somewhere between the various 15th edition amendments and the 16th edition (1992) the change was made to current operated devices, so this VOELCB did not even comply with the earlier edition pre-2008.

 

[jackofall]

I'm not very familiar with the UK regs but I had a feeling there was a 'competent person' clause somewhere that might have given you some more room for maneuver when it comes to RCD requirements.

Do these mobile units definitely fall under the scope of the normal installation regs? Do they come under the caravan regulations or maybe are they military etc?

You are perfectly right about the competent person bit, however, any mobile installation falls under section 7 now, and these do not conform. There is a stanag for military vehicles, but am sure there is no form of crown immunity of any kind, so they would still have to conform to the regs.

 

[spark 68]

Are you sure it is a VOELCB ? as we would normally understand it, could it not be an Insulation monitoring device ? or some other weird set-up ? IT system for example ?

 

[jackofall]

It is def a VOELCB, as you would normally have ripped out and replaced. Just at the moment, that option would prove to be very expensive, as in 6 figure expensive(min). But a redesign would be required to handle the earth leakage that is there.

 

[Lucien Nunes]

If this is standard issue kit, surely a test procedure will have been written and the necessary test gear requisitioned to maintain it already? Whilst the VOELCB might offer limited protection it should at least merit being tested to original spec, otherwise the system is unmaintainable.

 

[rattlehead85]

The VOELCB used for fault protection would only warrant a code 3 departure on an eicr as long as it is proved to operate correctly. However, if the means if earthing to it where inadequate i.e the use of a water pipe as the main earth this would then warrant the code 2 departure as previously mentioned in this thread.

 

[jackofall]

The thing is, VOELCB have not been used since about circa 1981 !, so it is not just pre-17th edition, but almost pre- or about 15th edition !



My 15th edition regs (first of this edition dated 1981) still has the test procedure in it for these, ie injecting a 45volt AC voltage across N and Earth.



Somewhere between the various 15th edition amendments and the 16th edition (1992) the change was made to current operated devices, so this VOELCB did not even comply with the earlier edition pre-2008.

　

This is something I did not know and helps me out quite a bit. As this nullifies the argument that has been used when I first got involved, and said this was not up to spec. I work more in electronics than electrics, which is why I posted this up and am really grateful for the helpful replies. Another part of the argument is that it was part of the original requirement to have VOELCB fitted, but to my mind the designer should have made the point that this was not up to current regulations and re-look at the requirements. This is not a back street workshop I am talking about.

I think I am going to have to go with the C3 option across the whole lot, and any that have failed to function at any time then its a C2. The worry I have is the user creating a pathway to ground in wet conditions and getting fried for his effort, should the installation ever go live and the units fail to function correctly. This is a lovely can of worms that I have to open, and will make me instantly popular, but the supplier needs to take some responsibility here.

Has anybody ever had experience of a supplier providing kit not up to regs? and had to fight to sort it out?

 

[alanl]

This is getting a little confusing - where can you buy VOELCBs in the UK today?
Is there a specific reason why one is used rather than a standard 30ma RCD?
No decent Designer would specify a VOELCB without good reason, as it is clearly not compliant with the Wiring Regs for a new installation.
The VOELCB may well give a sufficient additional protection, but, it cannot be verified unless you have the specialist equipment to do that, even then,it will not comply with the Regs, and in my view, will not comply with one of more of the vehicle supply regulations, as the electrical install in it cannot be proven to be safe.

 

[jackofall]

This is getting a little confusing - where can you buy VOELCBs in the UK today?

Is there a specific reason why one is used rather than a standard 30ma RCD?

No decent Designer would specify a VOELCB without good reason, as it is clearly not compliant with the Wiring Regs for a new installation.

The VOELCB may well give a sufficient additional protection, but, it cannot be verified unless you have the specialist equipment to do that, even then,it will not comply with the Regs, and in my view, will not comply with one of more of the vehicle supply regulations, as the electrical install in it cannot be proven to be safe.

There are a couple of reasons that have been quoted to me for this setup. The first one, that it was stipulated on the original requirements, and as I have mentioned before, I think this should have been kicked into touch then. The next, they cant use and RCD due to the amount of earth leakage within the platform, which to me indicates bad design as you can always sort that out during the design stage even if you have to go to the extreme of rectifiers and invertors with the ccts split up etc. That could have had its own advantage of beefing up the UPS system as well.

But as to where you can buy them, you got me there, as not on the procurement side of life.

 

[alanl]

If there is that much earth leakage ( >30mA), then it is not safe, unless there are some exemptions for its continued use.
There is a reason for the 30mA limit.
Touch the chassis as you are getting out, you then see the earth spike hasnt been fitted, but your foot is about the touch the ground - you will be the earth spike, and over 30mA has the potential to stop your heart (ok, for the majority of blokes, it isnt a problem, but a child, or old lady touching the body could be badly shocked)

 

[jackofall]

Lets put it this way, the 100mA would not be suitable in the current setup, and I believe the 300mA might struggle(obv this would only provide protection to equipment, not life). I realise these figures sound stupid, but I promise its right. There are many things wrong here, but its a massive uphill struggle that people don't want to face as it admits mistakes, then its down to who will pay for it. So its not as easy as whipping the VOELCB out and fitting an RCD. Other issues have to be tackled at the same time.

 

[Marvo]

.... The next, they cant use and RCD due to the amount of earth leakage within the platform, which to me indicates bad design as you can always sort that out during the design stage even if you have to go to the extreme of rectifiers and invertors with the ccts split up etc..

Why is the standing leakage so high? Aren't RCBO's a possibility or even retrofit with these puppies



Theres lots ways to decorticate the cat.

 

[spark 68]

In cases of high leakage where a 30mA RCD cannot be used Electrical separation may be used instead, this could be part of the generator itself, this is taken from the limited information given in GN7.