Laos - no earths, no RCDs... advice please

[Schwuppes]

Hi everyone!

I've just recently moved to Laos PDR and was shocked (no pun intended) to find that the whole house has no earth wire (i.e only Live and Neutral) going to all sockets and appliances... to top it all off also no RCD's... its completely ridiculous.
I am not an electrician and have only basic knowledge of electrical stuff. But i believe I am totally unprotected in this scenario...

Now... would it be acceptable to run a seperate earth wire from each appliance say through a drilled hole in the wall to a copper earthing rod into the soil? Kind of like a TT earth but individually for each appliance? I will limit the use of anything thats not double insulated as much as I can... but a few things like the hotplate and instant shower water heater I can't avoid. An electrician actually came today and installed such an earth as I described to the shower instant water heater at least (my landlord's comment was "we normally don't use earths except for the water heaters... lol).

Anyway Id like to ask if there is anything wrong with this... I'm thinking of voltage potentials between the improvised earths and say metal pipes etc. Apart from the fact that the resistance of the copper rods would be too high to trip the MCB (at least they have those here lol)

Which brings me to the second part of my question: if I were to use those portable socket RCDs... would they work? I'm guessing it would be better than nothing, right?

Sorry for long post, thank you

 

[Dan]

Thanks for posting here.

That sounds bloody lethal! - I can't help you out I'm not an electrician, but I'll watch this thread because this sounds crazy!

 

[davesparks]

Installing multiple earth rods and connections as you suggest is a bad idea. If you are going to earth it tune it all needs to be connected to the same earth, not a bunch of different ones.

My first question is whether the supply is actually earthed? If the supply neutral hasn't been reliably connected to earth at source then any earthing you add won't achieve much except a false sense of security.

 

[Schwuppes]

Hi guys, yes it is completely crazy...

Well there is no way i can rewire the whole building myself... the landlord won't do it either. Why is it a bad idea to have multiple earth rods? Im not doubting you but would just like to know why? Earth loops or something like that? Surely having sone earth rods is better than none at all?

If the neutral is earthed i don't know... if i had a multimeter i could measure between one of the earth rods and neutral i guess... but i don't have one.

Regarding using portable RCDs at the sockets... also a bad or useless idea?
Cheers

 

[Schwuppes]

How do you edit posts here lol

I was just thinking... in theory in this case.. wouldn't it actually be safer if the neutral was not earthed?

Because that way my body would never complete a return path for any fault current appearing on a metal chassis. Or wait... for that the whole utility electricity network would have to be floating... not just my house, right? Jeez this is doing my head in lol
I know I'm probably being a bit silly... but I'm really trying to get my head around all of this.

Edit: found the edit button haha.


Just thought about the multiple earth rod issue a bit more... say I put 3 individual ones into the ground, 1 each for water heater, washing machine and hot plate for example... Each rod will probably have a different loop resistance to ground (Ra, right?). So if the hotplate has a fault it could actually energize the chassis of the remaining two appliances, is that (part of) the problem with my suggestion?

 

[Kidsolo]

If you go creating an earth on all outlets and appliances you better make sure the main neutral is earthed , or you will create your own personal "death trap"

 

[Schwuppes]

Hi mate,

Yeah I was thinking something like that too... I can only assume they earth the neutral at the distribution transformer... I'd imagine it would be an absolute pain in the arse for the power utility company (let alone the end users) if they didn't... considering the almost daily lighting storms etc. But I will try to find out for sure.

I know I'm trying to polish a turd here lol...

So I'm thinking to just use only one earth rod connecting directly to the instant water heater... so at least that is earthed by itself. Would that be OK? (And regardless of whether they neutral earth the neutral or not?)

And for everything else I'll just use some of those 30mA socket piggy-back RCD's?

Basically what I'm trying to ask is... given this ridiculous situation I have to work with... what would be the next best thing to make it at least a little bit safer? Or better to just leave it as it is?

Thanks guys


EDIT: OK just read a PDF of the Lao electric power technical standards... most LV distribution has the neutral not grounded... this just keeps getting better... you can't make this stuff up.

So I should probably disconnect that earth rod from the water heater again?

 

[dmxtothemax]

you use plug in style RCD's on each outlet,
there does not have to be an earth for them to work.
If you have multiple earths this can cause havoc with board mounted RCD's.

 

[Schwuppes]

Just incase anyone thought I'm having a laugh (I wouldn't blame you lol) I've attached a screeshot of the PDF...

Thanks so far guys. If anyone else has any more comments or can educate me more please do so

 

[Robson689]

I think you should consult a specialist within your country as mistakes made could be fatal if you unknowingly create a dangerous situation.

 

[R-fur]

I agree with Robson689, get some local advise. It looks like you have a 25kV earth return system ie one overhead line conductor which feeds one HV terminal of the transformer the other terminal is connected to a spike so normal load current flows through earth. This will give strange voltages in the ground. The LV side looks like it is an IT system. Neither of these systems are allowed to be used for public distribution in the UK.

 

[Schwuppes]

I agree with Robson689, get some local advise. It looks like you have a 25kV earth return system ie one overhead line conductor which feeds one HV terminal of the transformer the other terminal is connected to a spike so normal load current flows through earth. This will give strange voltages in the ground. The LV side looks like it is an IT system. Neither of these systems are allowed to be used for public distribution in the UK.

Thanks mate, so if this is the case as you described... I'll just put everything back the way it was. I think I'm just making things worse potentially. Back to cold showers... it's actually kinda nice haha.

So on the primary side of the pole top transformer (facing the power station i guess?) there is actually current flowing through the actual soil back to the powerstation? How does that work? That return path resistance to the power station must be in the petaohms or something... o/c basically. But im probably missing something again

Yeah Ive contacted a proper european electrician from a friend here.
I cant be 100% sure, but based on some dodgy translating and hand gestures, the local "electrician" who fitted the earth to the water heater yesterday seemed to say that the whole house was "grounded", because there was a cable going from the brick wall into a ground rod and that everything was ok.

If you guys are interested I'll keep you updated

 

[UKMeterman]

Can we see some pictures of your local transformer?

 

[Lou]

Please keep us updated - we like to see how things work out

 

[Lucien Nunes]

If you go creating an earth on all outlets and appliances you better make sure the main neutral is earthed , or you will create your own personal "death trap"

I'm not sure what you mean - can you explain? There are systems that use an earthed equipotential zone that do not have an earthed neutral. Or, if the supply is floating, the RCDs might not trip to a single fault but that won't make anything more dangerous.

That return path resistance to the power station must be in the petaohms or something

It's actually pretty low. The Ra of an earth rod is mostly associated with the soil around the rod. Although soil isn't a great conductor, the cross section of the useful path to the substation over much of its distance may be measurable in square kilometres instead of square millimetres. So if both ends are equipped with a good mat, it can be in the same order as a metallic return conductor but it costs nothing. Earth return is used in sparsely populated places where it's hard to recover the cost of the line plant. Last time I saw it was in Iceland.