Why 2m max from EHU to the consumer unit?

[pappajohn]

You want the consumer unit as close to where the EHU enters the vehicle to minimise the length of cable inside the vehicle potentially unprotected by the vehicles RCD.

Example:
If a fault develops on the cable between the EHU entry point and the consumer unit, and the sites protection is not good say for instance the earth has been disconnected. There is potential for your vehicle chassis to become live. This could injure or kill any one touching your vehicle with their feet on the ground.

By minimising the distance between the EHU entry point and the consumer unit you are minimising the length of "risk". You should also as a matter of safety double insulate the cable by running it in conduit. I personally use copex/kopex flexible conduit in my self builds for this job.

Makes sense but why not fit the consumer unit directly behind the hookup point and illiminate the risk altogether.
It's probably a national caravan council (NCC) recommendation and nothing to do with electric regs.

 

[Gromett]

Makes sense but why not fit the consumer unit directly behind the hookup point and illiminate the risk altogether.

I agree. I am not sure but this sounds like a self build? If so then I would be jiggering the design to have the consumer unit next to the EHU socket.
Adding an additional RCD or RCBO next to the EHU is safer but it is an added point of failure. I always work on the KISS principle.

 

[ctc]

Think your overlooking the uptake of usage in electricity since the 1930s,

seriously trust the regulators on this, they know what they are talking about…

My point was RCD'S do not guarantee safety, a little common sense has to be used. Unless you have other problems a240v shock won't kill. My wife recently had a severe shock when an expensive RCD shorted to earth, the earth stakes were dry and the taps were live. They were live because the regulators say taps must be earthed for safety even when the pipes are plastic. For safety I did away with the RCD.

 

[Gromett]

My point was RCD'S do not guarantee safety, a little common sense has to be used. Unless you have other problems a240v shock won't kill. My wife recently had a severe shock when an expensive RCD shorted to earth, the earth stakes were dry and the taps were live. They were live because the regulators say taps must be earthed for safety even when the pipes are plastic. For safety I did away with the RCD.

I am sorry but that post made absolutely no sense. There is no earth connection on an RCD and it doesn't rely on an earth to operate. If your wife had a serious electric shock it would have had to have been a live to neutral shock if the RCD was not triggered. In which case the RCD did not fail and you have more serious issues to deal with. By removing the RCD you have removed an important safety device.

 

[Gromett]

For those wondering what I meant in my previous post. This is an RCD.

AS you can see there is a live in and live out on the left, and a neutral in and neutral out on the right hand side.

The RCD simply compares the current coming in on the live with the current returning on the neutral. If any is escaping it will trip.

If as ctc states

an expensive RCD shorted to earth

Then it is a problem with the wiring not the RCD.

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[ctc]

Sorry for laughing but that post made absolutely no sense. There is no earth connection on an RCD and it doesn't rely on an earth to operate. If your wife had a serious electric shock it would have had to have been a live to neutral shock if the RCD was not triggered. In which case the RCD did not fail and you have more serious issues to deal with. By removing the RCD you have removed an important safety device.

The unit was a RCD and socket combined wired by a qualified electrician, who insisted we have yet another earth stake. When I phoned and said what had happened they said the same as you, almost word for word. When he arrived I suggested he take a firm grip of a tap for some reason he refused and then removed the socket and fitted a normal one but said we had no earth refusing to switch on for safety reasons.

 

[Gromett]

The unit was a RCD and socket combined wired by a qualified electrician, who insisted we have yet another earth stake. When I phoned and said what had happened they said the same as you, almost word for word. When he arrived I suggested he take a firm grip of a tap for some reason he refused and then removed the socket and fitted a normal one but said we had no earth refusing to switch on for safety reasons.

You have a serious problem with your house wiring. So many issues with what you have said that I won't even attempt to respond.

 

[ctc]

You have a serious problem with your house wiring. So many issues with what you have said that I won't even attempt to respond.

We moved.

 

[Coolcats]

You are far more likely to be killed in your own home by a tea cosy (one in Suffolk some years ago)

Did they choke on it? Or a burglar use it as a blunt instrument.

Just checked my tea cost it’s made from wool and quite harmless

 

[ctc]

Did they choke on it? Or a burglar use it as a blunt instrument.

Just checked my tea cost it’s made from wool and quite harmless

The report didn't say, but three people died of bubonic plague the same year around 1963.

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[The Artilleryman]

Gromett I wonder if it was TT rather than TNS or TNCS.

Sorry for the thread slide.

 

[Cliff Bryant]

German van. they have different regulations to the UK?

Wouldn't the regs have been EU harmonised? Just asking as my Adria also has the EHU on the left side and the charger, consumer unit and batteries on the right side further down the van. I do agree about keeping the incoming cable short but if it was a real issue surely there would be a protection device as part of the commando connector assembly. Personally I worry more about the line and neutral being swapped at the campsite post, never had that happen at home but quite a few times in Europe. People leaving their 25m or 50m cables coiled up in the sun worries me too.

 

[rod_vw]

Are there really any 'regulations' or are there just words put about by those who either don't know any better or think they do?

As for armoured cable not being suitable, why not use this? https://www.tlc-direct.co.uk/Products/MF2dot5slash3.html? It looks to be industry standard for 240v distribution in difficult locations and maybe there is a version with a bigger cross sectional area if required.

That is probably what I would use if it concerned me.

 

[Gromett]

Gromett I wonder if it was TT rather than TNS or TNCS.

Sorry for the thread slide.

I am not sure how this would affect the operation of a properly installed RCD?

If you were to touch a live conductor and current was to pass through your body to ground (an electric shock) that current would not return through the neutral and would therefore cause an imbalance and the RCD would trip.
It doesn't matter if this leakage is going through your feet to ground, or through an earth bonded bit of metal.

If you are insulated from the ground and touch the live conductor then no electric would pass through your body and all current would return through the neutral and would therefore cause no shock and no imbalance.

I can't think of any middle ground?

The above all presumes that the RCD was correctly installed, tested and working.

If it was a TT earthing system which sounds plausible then I still don't see how the above would be wrong?

In my opinion to get a shock there would either have to be.
a) a faulty installation
b) the person being shocked was touching both live and neutral.

If the latter then the RCD is not at fault as it is not designed to protect in this situation. The fault is with the installation as there should never be an access to live and neutral conductors.

I am having a think about how say a stainless steel sink could become live if there was an RCD installed.

If there was a fault that allowed a live cable to touch the earth conductor and the earth spike wasn't connected. It is possible for the sink to be live.
HOWEVER. The second you touch it, there will be a leakage to earth through your body and the RCD would trip????

It has been a very long time since I downed tools and when I was doing my apprenticeship RCD's were not a common item in any installs. In fact from memory (and it is fading), the 15th edition only required them for outdoor circuits.

There will be people here with more up to date knowledge on this who will not doubt correct me.

Here is my position though for clarity.
1) RCDs are a major step forward in the safety of supply.
2) They protect against leakage faults only, They do not protect against live/neutral faults or short circuit faults.
3) They should be installed correctly and as near to the entry of the building/vehicle of the supply as possible.
4) They should be tested regularly.
5) If you have a correctly installed RCD and you are getting shocks. Something is seriously wrong with the install.

 

[Gromett]

Personally I worry more about the line and neutral being swapped at the campsite post

That is why I recommend dual pole RCBOs or MCBs (with RCD) in motorhomes that are going to be travelling abroad.

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[Cliff Bryant]

That is why I recommend dual pole RCBOs or MCBs (with RCD) in motorhomes that are going to be travelling abroad.

I concur. I also think RCBOs should be the order of the day in almost all normal cases. What price safety or not having your van catch fire.

 

[Gromett]

ok. I have just wracked my brain on this and can think of one way.

The sparkie who did the install was incompetent? I presume it was a device like this that was installed?

The only way I can think for this to have caused a problem is.
a) The installer swapped the live and earth conductors on the back of the socket and the back box was metal and was already earthed.
b) The new earth spike was not installed correctly.
c) The house was not protected by an RCD at the consumer unit.
d) The installer did no tests on the system.

This relies on multiple failures and a deep level of incompetence that is beyond criminal?

If the installation had a properly installed RCD in the consumer unit, it would have protected against this situation.

Any one else think how this could happen?

 

[Gromett]

I concur. I also think RCBOs should be the order of the day in almost all normal cases. What price safety or not having your van catch fire.

The only advantage of an RCBO over an RCD/MCB combination is that you only lose the circuit under fault not everything.
So if the boiler causes a trip you don't lose your lights for example. I don't think RCBOs improve safety over an RCD.

The key bit is that it must be dual pole though. That is the critical bit for vans.

 

[Cliff Bryant]

The only advantage of an RCBO over an RCD/MCB combination is that you only lose the circuit under fault not everything.
So if the boiler causes a trip you don't lose your lights for example. I don't think RCBOs improve safety over an RCD.

The key bit is that it must be dual pole though. That is the critical bit for vans.

The RCBO can be specified to trip at a lower overload current than tripping at the higher current of the upstream circuit protection. It can provide a more granular level of protection but in practice the advantage of only tripping one circuit is the major one.

 

[Coolcats]

The report didn't say, but three people died of bubonic plague the same year around 1963.

I’m not off to Suffolk any time soon then

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[TheBig1]

There is near chapter and verse written above on why the regulations are there to protect the end user and anyone else that might come into contact with the installation

What bothers me is the unqualified answers of others that see the regulations as mumbo jumbo or whatever term. Safety is the primary concern of absolutely any installation and when such an installation is made in a vehicle, that concern is even greater. Vibration and corrosion are a factor there that you rarely see in buildings. And especially where such an installation may be being carried out by an unqualified person DiYer, the onus is on the installer to ensure it is perfectly safe for themselves and absolutely anyone else that might come into contact with the vehicle. A poor install and linked to a hook up without Earth bonding, will be a potential death trap

When you have seen as many poorly installed cables and corrosion as I have, you will understand. Even some converter created faults are a regular occurrence. Such as wires coming loose on the back of the hook up socket.

 

[TR5]

I don't know how many people have died from electric shocks in their vans but I think no matter what length cables the risk is nonexistent to minute. You are far more likely to be killed in your own home by a tea cosy (one in Suffolk some years ago)

Every time that cable is 'live' the risk can never be non-existent, however small it may be. It makes perfect sense to minimise ANY risk, however minuscule it may be, if it's viable and practical to do.

 

[TR5]

Look at the figures, there has been little or no reduction in deaths from electric shock from the 1930's. All that's happened is plug tops and sockets are now a little more child proof , my youngest grandchild can open the shutters on a socket with ease, he's 6. So there is a small reduction in child deaths, adults remain about the same. Your library can get the Observation Society's book listing the older figures, the latest are available in council reports which is where the famous tea cosy death comes from.

Well, that analogy just doesn't add up.
Population increase since 1930 is 47%. Housing increases will be that figure or larger. The increase in the number of electrical appliances and outlets in houses now, compared to those that actually had electricity installed in 1930 has got to be at least 20 to 30 fold.

No comparison, sorry!

Electrical safety has done very well to stop death tolls rising, in these times.

 

[Coolcats]

In the mean time we are all using more Lithium batteries, remember to unplug charges before bedtime and only use the correct charger for the device.

Recently there has been posts and discounts for the fire safety stick which many functors including myself have purchased.

Given that electrical fires do happen its worth considering investing in connected Heat and smoke alarms that are linked in the home so you hear the thing should something catch fire anywhere in your home (e-bike, mobile, computer, tumble dryer etc)

Many of us have Fire Angel in our Moho but how about a heat alarm in the kitchen that is connected to smoke alarms around the home along with a CO detector all connected

I suspect the bigger danger at home is Fire rather than electrocution

This video shows a dodgy battery in a lap top

 

[Hoovie]

The only advantage of an RCBO over an RCD/MCB combination is that you only lose the circuit under fault not everything.
So if the boiler causes a trip you don't lose your lights for example. I don't think RCBOs improve safety over an RCD.

The key bit is that it must be dual pole though. That is the critical bit for vans.

A key advantage, especially on a motorhome is the spacesaving an RCBO provides over an RCD + MCB in the consumer unit.

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[Gromett]

A key advantage, especially on a motorhome is the spacesaving an RCBO provides over an RCD + MCB in the consumer unit.

Not convinced that is a such a big thing to be honest. Not much of a size difference between a 4 gang and a 6 gang consumer unit?

 

[Gromett]

A key advantage, especially on a motorhome is the spacesaving an RCBO provides over an RCD + MCB in the consumer unit.

Oh. Just checked and you can get single module dual pole RCBOs. I didn't realise they were a thing.

Suddenly your point on space saving makes sense

 

[3alpacas]

I agree. I am not sure but this sounds like a self build? If so then I would be jiggering the design to have the consumer unit next to the EHU socket.
Adding an additional RCD or RCBO next to the EHU is safer but it is an added point of failure. I always work on the KISS principle.

Yes, a self-build - with a layout originally designed on the KISS principle of purchasing a Sargent EC155 and using the full near-2metre length of the cable that is supplied with it to get power from the EHU (why otherwise would they supply a cable of that length? - no need to answer that, of course!).....hence my original question :.....because I had been advised to purchase an AVS30 surge-protector to provide additional protection to the two small compressor fridges and the Truma combi, so I could 'push' the Sargent just a little further into an internally accessible space.

The KISS principles fell apart a little, of course, once I began to find out a bit more about the limitations of the Sargent, and it is a fairly big beast in comparison to the other kit that is currently designed to lie nearer to the EHU and LB (Renogy Rover MPPT, Victron B2B and Victron 240-to-12V chargers, shunt, etc. - the arrangement hopefully optimising the challenges of limited space - so relocation cascades quite a few 'dominoes' (including the location of the various associated control/information panels). I spent a couple of hours 'playing tetris' on Sunday evening but only ended up creating some significant dead space in the garage each time (before giving up in despair, because the now somewhat immovable Truma 'gets in the way'). But I'll crack on with installing the under-floor water tanks tomorrow and hopefully get a different perspective on how to resolve this along the way.

 

[Gromett]

KISS principle of purchasing a Sargent EC155

That is not where I would have started from sadly. I hate integrated things like that because if one bit goes wrong you are stuffed for the whole system. I always go with separate components.

But you have already committed so I am afraid I can't advise on the Tetris project.

If you do have it any distance from the hookup inlet here is what I would do.
Ensure it is not in any cupboard or alcove where anything could be dropped or shoved into it.
Protect it in at least copex/kopex flexible conduit and try to secure it off the floor. Do not leave it flopping around.
I would do it in such a way that you can get to it after the build is finished so you can inspect it if necessary.
Make sure that if it is damaged it cannot touch any exposed metal work that is connected to the chassis.

Just a silly question. You may not be able to move the EC155 to the EHU inlet. BUT can you install an inlet nearer where the charger is going to be? ie can you move the inlet?

 

[The Artilleryman]

Oh. Just checked and you can get single module dual pole RCBOs. I didn't realise they were a thing.

Suddenly your point on space saving makes sense

Yes, I upgraded my home c/u split board to RCBO and gained 4 extra slots for future circuits.

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