Earth where no earth exists, on 12th floor.

[Crossy]

1 hour ago, digbeth said:

the tv aerial should be grounded right? what issue could arise from tapping ground from the co-axial cable that's likely unused these days, but in condo building these would have been ran through splitters and amplifier to your room, would the ground still be good

 

I would definitely NOT do that; the system may well provide an earth but there are likely all sorts of "stuff" in there too.

 

Building re-bar or a metal water pipe (but NOT the fire system) would be much better.

[Crossy]

3 hours ago, bluejets said:

Safest way for you as a dilutie (non-qualified, learned by word of mouth) would be to simply fit RCD combos to all the circuits and forget about the earthing.

 

Chances are you will end up connecting YOUR earth returns to metal which has absolutely no reference or a high impedance to ground and fry some other poor bugger during an earth fault.

 

If there is a good proven earth cable found by standard proven methods(not building reo by the way) no MEN connection would be necessary nor would it be recommended as the main supply and other sub-boards are within the same structure/building.

 

I agree 100% on your sentiments on the RCD/RCBOs, essential!

 

Of course, if there is actually a pukka ground in the cabinet of course it should be used, we have to assume our OP's sparks has failed in his quest to find one.

 

Running Class-1 appliances with no earth whatever is unwise, even if we consider they are safe by being fed by and RCD/RCBO there is still the matter of "functional earth".

 

Equipment with switching power supplies or inverters (pretty much everything these days) will have a mains filter many of which have capacitors between L and N and E. These form a high-impedance voltage divider putting the E (and any metalwork) at somewhere near 50% mains.

 

The available current is tiny and of no hazard in itself, but it may give a significant "tingle" to the user which can be disconcerting to say the least.

 

Even a poor earth (building steel) will kill the tingle, it would probably also provide enough current to trip the RCD in the event of a L-casework fault.

 

As an aside, the roof steel of our house actually measures as a better earth than our pukka 2.5m copper-clad steel rod (we have a lot of 16m driven piles). Ufer or concrete-encased electrodes are much better earths than many would expect.

 

 

[Johnlkuk]

On 2/18/2024 at 9:48 AM, Crossy said:

Of course, if there is actually a pukka ground in the cabinet of course it should be used, we have to assume our OP's sparks has failed in his quest to find one.

 

Correct, no earth found after a good search. There's just live and neutral coming into the condo (red and blue) 

[Johnlkuk]

An update after some more success using the rebar. 

 

1st picture using live and neutral from a socket:

 

[Johnlkuk]

Then connected to one rebar:

 

 

 

And then with 2 rebars connected:

 

 

[Johnlkuk]

Looks as bright as using the neutral, so I'm well happy. 

Cable and clamps courtesy of Lazada. 

[Johnlkuk]

[Johnlkuk]

Next I'll do the same up in the bathroom ceiling and then connect the two together and send back to the CU ready for a 3 core cable changeover sometime in the future (after the RCBO/CU upgrade). 

 

Many thanks again for the help and advice, and particularly much respect to you Crossy for sharing your knowledge. 

👍

[Dan O]

On 2/15/2024 at 10:37 PM, Johnlkuk said:

As the title says: is it even possible to create an earth on the 12th floor of a condo block?

 

I recently purchased the condo in an older block (1992 build) and have found issues with the electrics. Apart from there being no earth, there's several circuits that are joined together and protected just by the main breaker. Photo attached

 

An electrician friend of mine was here for a few weeks and the outcome of an assessment was to change the consumer unit, and to  fit the new with individual RCBOs. 

The idea is to buy what I need back in the UK and to bring it all over next time. 

 

Without my friend here to ask right now, I am wondering again about the lack of an earth.

Is it possible to find an earth up here on the 12th floor (all plastic pipework as far as I can see), is it even super-important to have one, or is there another option (I read on this forum about combining the neutral and earth, if that's the right term).

 

Look above the ceiling if you can. Check for the sprinkler system pipes if you have them or metal beams that are exposed.  Rcbo will be sufficient I belive even without an earth. Most likely none of your wiring have a ground wire anyway

[Johnlkuk]

Several months later and I am back over and working on the electrics.

I've made good progress, but is it OK to continue this thread even though the earthing query has been answered, or should I start a whole new thread? 

I've now made the CU changeover and it would be good to keep all the info together. 

 

[Crossy]

31 minutes ago, Johnlkuk said:

Several months later and I am back over and working on the electrics.

I've made good progress, but is it OK to continue this thread even though the earthing query has been answered, or should I start a whole new thread? 

I've now made the CU changeover and it would be good to keep all the info together. 

 

 

I'd start a new thread with a relevant title, makes it easier for search-engines to find your content.

[Johnlkuk]

1 minute ago, Crossy said:

 

I'd start a new thread with a relevant title, makes it easier for search-engines to find your content.

 

Thanks, will do.