VOELCB question pre regs change, but still in use.

alanl said:

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.

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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.

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)

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.

jackofall said:

.... 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..

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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.

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.

Marvo, its the whole installation that I am looking at for the isolation aspect. There are separate ccts inside with RCD protection for plugs, but there is a combination of AC and DC equipment's being used. The DC if I remember is on magnetic cct breakers. Gets better and better the more you look into it. But I am only really looking at the whole platform issue at the moment to ensure electrical safety and that it can be used. Then to come up with some form of solution to prove/disprove the reported problem of VOELCB not tripping when earthed correctly.

As already stated here, many times actually. You're VOELCB is now an obsolete protection device that can not be easily tested or maintained so you don't really have to prove anything. Parallel earth paths were always the downfall of the voltage operated earth leakage breakers....

Not really knowing what the make-up of this this mobile truck is all about, we can't really comment further. Save to say that RCD devices come in many different forms, many with adjustable time and leakage current parameters. With a little bit of thought and know how, adequate earth leakage protection using one or more forms of RCD's can in most circumstances sort out any high leakage problems you may have!!