house earthing system

[Nijinski001]

I posted a question some weeks ago where I found a light fitting with no mains earthing available the earth and neutral had been bridged. As there was no earth on the lighting circuit they seem to have used this as an alternative method of protection. Although the practice it was agreed was dangerous, one of the guys on the forum said it was a common practice in the Eastern block.

Could it be that whoever has done this has employed a non qualified immigrant worker?

Also an observation - Is this the only fuse box in the property? The main incomer is 60A. Unusual for a domestic uint not to have 100A mains incomer switch?

 

[Steve]

yeah some of those mcbs look suspiciously wired, i mean, whats with the sequence: 30, 15, 5, 15, 5??

where do the 2 cables on that 5A one go?

why is there a 2.5mm²<?> on the final 5A mcb?


Other than the earthing conductors of the whole house not being connected, is there anything fundamentally wrong with connecting the neutral to earth like this, in the CU? I mean, is it dangerous? Where would the current flow, back thru the neutral or down the earth? My understanding is that the neutral is connected to earth at the substation anyway, so is there anything wrong with doing it here, in a CU instead/as well?

 

[ban-all-sheds]

Look at the CU again.

Imagine a L-E fault on an appliance - where/how does the current in that circuit's cpc flow in order to operate the protective device?

 

[DDoyle]

The simplest solution would be to contact a professional electrician and get them to put things right, as they blatently are not from the picture posted.

 

[Qedelec]

Other than the earthing conductors of the whole house not being connected, is there anything fundamentally wrong with connecting the neutral to earth like this, in the CU? I mean, is it dangerous? Where would the current flow, back thru the neutral or down the earth? My understanding is that the neutral is connected to earth at the substation anyway, so is there anything wrong with doing it here, in a CU instead/as well?

The problem is serious in that nothing in the house will have a safe path to earth. Remember that in this country all appliances rely on a safe earth connection.

 

[Steve]

Other than the earthing conductors of the whole house not being connected, is there anything fundamentally wrong with connecting the neutral to earth like this, in the CU? I mean, is it dangerous? Where would the current flow, back thru the neutral or down the earth? My understanding is that the neutral is connected to earth at the substation anyway, so is there anything wrong with doing it here, in a CU instead/as well?

The problem is serious in that nothing in the house will have a safe path to earth. Remember that in this country all appliances rely on a safe earth connection.

(read the bit in bold, i appreciate that there isn't a safe path to earth in this case, i was wondering if there is anything wrong with connecting neutral to earth at the CU, apart from it not being normal practise - they are connected in DNO fuse enclosures on a TNCS system, why not do it at the CU?)

 

[ban-all-sheds]

Read the other bit in bold:

Other than the earthing conductors of the whole house not being connected, is there anything fundamentally wrong with connecting the neutral to earth like this, in the CU?

It's the doing of it like this that creates the situation of the earthing conductors of the whole house not being connected...

But if you mean bridging earth and neutral within the CU as opposed to connecting the CU neutral to the MET, this will trip the RCD on a TT installation, make no difference on a TN-C-S installation, and with a TN-S supply I guess create the broken neutral risk that PME is designed to avoid with TN-C-S supplies...

 

[Spark123]

It is also in violation of ESQCR for a consumer to use combined neutral and protective functions in a single conductor.ESQCR, 8 (4)

 

[lizzieg]

thank you all for the replies....glad its not me being paranoid again LOL

Have moved earthing conductor to earth bar.
Well spotted qedelect, yes that is indeed a 1.0mm square cable coming from a 15A fuse feeding........wait for it........a radial circuit in the kitchen !!!!
needless to say I am not using the double socket that this cable runs to anymore, until I get a chance to sort it out.

As to the two conductors coming from one of the 5A fuses, thats easy........some bright "spark"has taken one of the wires to the light switch at the top of the cellar steps to use as the switch feed.

the other 5A ( with the 2.5 twin + cpc) runs to the house burgler alarm panel, again I dont set this, it just has lights flashing on the box outsideand the pirs in the house lighting up, if you know what I mean

the one and only ring final circuit has spurs everywhere and I am at present digging the socket covers out of the plaster to see what is what.............fun this lectric lark, isn't it

 

[HDRW]

Why is it like this...

Let me make a few wild guesses:

1) Stupid mistake
2) Couldn't fit it in the earthing block and found somewhere else it would fit
3) trying to invent his own way of making a TN-S-C (!) system.

4) It was wired by an American electrician? As I understand it, over there they always have the Neutral connected to Earth at the house (it's the centre-tap of a 110-0-110 transformer winding and if it wasn't earthed ("grounded") it would float in relation to Earth).

Incidentally, where does that large green/yellow cable that *is* connected to the Earth bar go to (leftwards)?

Cheers,

Howard