Making Sense Of My Meter Cupboard

[PMC1959]

Hello everyone, whilst new as a contributor I do read this forum all the time and do understand the basics of electrics.
I have just purchased a new ground floor flat which has storage heaters and (I assume) Economy 7. I want to get rid of these but thats another story. As a matter of interest I have been trying to understand what all the cables mean in my meter cupboard (Diagram enclosed) I understand the block but what puzzles me is the link between the 2 meters, why are there so many and what do they do, could anyone enlighten me in laymans terms please. The sizes of the cables aren't necessarily accurate but represent the differences between each other.

Also, this is a purpose built block of flats circa 1960. There is no main fuse so I am guessing this is in a centralised cupboard somewhere, but I can't see any Main Earth coming into the fuseboard. I have taken off the front of the board but still can't see any incoming earth.

One last thing (sorry!) having checked a few switches and ceiling roses, there is no earth on the lighting. I guess this is a rewire job, but with concrete ceilings how is this possible as I don't relish trunking all over the ceiling?

Thanks in anticipation.

Peter

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• PMC1959
• 6 Jul 2009
• 3

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[Taylortwocities]

A photo would be of much more help, can you post one please?
Details on how to do it here //www.diynot.com/network/DIYnot/albums/67/180

In general:
All of the cabling relating to the meters, except for the "tails" to the two consumer units is the property of the electricity company (DNO) and you should not touch, alter or remove any of it.

What is the significance of the numbers on the cables, is this the size? How did you determine it?

The links will probably be feeds to the off peak meter - it will depend on the type. The pic will help.

In flats, there is usually a central cupboard (probably on the ground floor)where the incoming mains arrives. There should be a switchfuse for each flat.

If your flat is all concrete then you will probably find that the cabling is run in steel conduit. Is it? If so this may provide the earth to the socket circuits. There may not be an earth to the lighting (depends on the age of the installation) so you'd be stuck with only using plastic or double insulated fittings & switches there.

You'd have no chance chasing out concrete - trunking is bad option, you could batten out the ceilings and put in a false plasterboard ceiling but I'll bet your walls are concrete too?

 

[PMC1959]

Thanks Taylortwocities

The numbers do indicate the sizes but they are probably not correct, I put them in to show the differences between them all (ie the 6mm may not be 6mm but its smaller than the 10 - which may not be 10 if you know what I mean).

I will try and get some photos' posted tomorrow.

Yes! the walls are concrete also, its a nightmare. The cables for the storage heaters are all in trunking along the top of the walls and looks horrible.

I can't see any conduit when I remove switches or sockets. My main concern was I couldn't see a main earth. The 2 incoming tails come up through a hole in a metal frame to which is attached the metal fuse box I was wondering if somehow this is how it is earthed.

There is a central cupboard with danger notices on the door, I guess this is where the switchfuse is located.

 

[ColJack]

photo's of inside the ceiling rose and switches too..

it'll be either in conduit, or it may be wired in MICC, in which case there will be no "visible" earth since it's done by the sheath of the cable or the conduit itself.. there should be fly leads to the backbox though..

 

[PMC1959]

Photos added.

The battereries ran out before I could do the socket or switches. I couldn't see any conduit coming into any of the backboxes and there were no flying earths.

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• PMC1959
• 7 Jul 2009
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• 7 Jul 2009
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[Lectrician]

It is a standard econ 7 setup with dual rate meter and teleswitch.

All lecky is cheap at night.

It is wired a little oddly, looping the live from the meter via the teleswitch. It is usual to use a henley for this.

Not mush more to add, other than the DNO monkey was not very tidy.

 

[ColJack]

ok, so from what I see..

the first meter ( on the left ) is a dual rate meter.. this records how much you use peak and off peak..

the second "meter" is the teleswitch this turns on and off certain times of day..

it has a red and black supply to it from the incomming of the meter ( the small cables) and a signal cable back to the first meter to tell it it's off peak time ( the other small red cable ).

the output of the first meter goes to the teleswitch on the very left big cable. the next big red cable along is the general use power, which goes to the general use CU via the block ( the neutral goes straight to the block from the first meter and on to the general use CU and the heating CU ).

the grey cable marked with red tape is the off peak power and goes straight to the heating CU. this is only switched on when the teleswitch says it's off peak time..

I see earths on the left though where they go to or come from I cannot tell..

we'd need to see the grey CU with it's cover off to see if / where your earth comes from ..

 

[ban-all-sheds]

Not mush more to add

Holes in the top of the fusebox not sealed?
No grommets in said holes?
How smooth are the edges of the cut-out in the trunking where the tails emerge?
What's going on with that disconnected cable with tape over the end?
What sort of join is that in the cable just in front of the disconnected one?
Is there actually a main earth?

 

[ColJack]

What's going on with that disconnected cable with tape over the end?
What sort of join is that in the cable just in front of the disconnected one?

you mean the red one that's the other disconnected one to go with the black disconnected one? they're both doubled back if you look BAS..

 

[PMC1959]

Thanks for the input, it makes more sense now. The earths you can see on the left - 2 go into the fused switch (thats for a heated towel rail in the adjoining bathroom), one goes into the econ 7 fusebox.

I still cannot see any sign of a main earth which is worrying.

I have arranged for the Elec company to come and put a new meter in next Tuesday and remove the Econ 7. They are also putting in an Isolator for future CU change/rewire (as recommended on this forum). I will ask about the main earth when they come.

As an aside there is an extractor fan in the kitchen and bathroom neither of which I could get to work. One day they suddenly both came on and wouldn't turn off. Eventually after 3 days I did some investigative work and on the wall over the cooker hood was a fused switch, I turned this off and the fans stopped. My wife had stored some oven trays on top of the hood and accidently turned it on. Not really the most convenient place to switch on the bathroom fan!

 

[mbelectric]

Rather than start another thread I may as well ask this here if thats ok.

 

[ban-all-sheds]

you mean the red one that's the other disconnected one to go with the black disconnected one? they're both doubled back if you look BAS..

Doubled back and taped over is NBG if they are still live...

 

[ColJack]

I'd assumed they were pulled out of the CU and taped up, but I can't see for definite where they run

 

[securespark]

Could the trunking be the earthing conductor supplying the installation?

 

[ColJack]

that was my thought too..
presumably SWA from wherever the main fuse is ( bad design not to have a switch or a "dummy head" in the flat if you ask me... ), and it's made off into the trunking. using it and the coupler to earth the metal CU attatched to it.. ( again, a bad design, what's wrong with a nice cable to the banjo? )