Ask The Trades - Lifetime of red/black cables?

Lectrician

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Re: Lifetime of red/black cables?
Reply #10 - Nov 11^th, 2016, 2:52pm

It doesn't look too big that cable. On that distance, I would expect a far larger cable.

Volt drop will most likely be exceeded when you draw larger loads, and the earth fault loop impedance may well be exceeded too, depending on what protection is up at the origin.

A good test for volt drop would be to turn some lights on, and then switch a decent load on/off, such as a heater, immersion, cooker etc. If you notice a substantial drop in brightness, you have volt drop issues.

Earth fault loop impedance can only be checked with a meter, but if voltage is an issue, earth fault loop is bound to be.

If the earth fault loop is exceeded, it means that a fault inside the consumer unit or on the cable up to it, may not clear within the 5 second disconnection time. It could take far longer to cause the fuse/trip to operate.

Have you considered getting an Electrical Installation Condition Report carried out?

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londonman

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Re: Lifetime of red/black cables?
Reply #9 - Nov 11^th, 2016, 7:37am

Now here's an interesting thing. The electricity meter is locate 0.26 miles away (yes, a quarter of a mile away) at a farm. I haven't seen it but can only assume that the company fuse is also there.

This property was totally renovated 'within the family' back in 1979 and the location of the meter is that of a relative. I have a nagging feeling that the main incoming cable was done 'on the quiet' and so God knows what's going to happen when I get a proper electrician along to replace the CU.

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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8727 Total Thanks: 96 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Lifetime of red/black cables? Reply #8 - Oct 28^th, 2016, 7:22pm That consumer unit is crying out for replacement. The wiring doesn't look too bad. The armoured cable feeding the consumer unit likely supplies an earth, but you would need to confirm at the sourcing end.
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londonman

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Re: Lifetime of red/black cables?
Reply #7 - Oct 27^th, 2016, 10:11am

Lectrician wrote on Oct 24^th, 2016, 8:44pm:

The earth may already be present, but not connected. It may be a TT system, which would be fine if a rod existed and main RCD.

Photos of any of the incoming bits?

A CU upgrade would typically cost in the region of £300-£500, but really depends on area, how many circuits, etc etc.

Northumberland/Cumbria border

I know...no meter in shot. Don't know where that is but going up in a couple of weeks so I can look then.

If you can recommend any electricians near Brampton ??

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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8727 Total Thanks: 96 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Lifetime of red/black cables? Reply #6 - Oct 24^th, 2016, 8:44pm The earth may already be present, but not connected. It may be a TT system, which would be fine if a rod existed and main RCD. Photos of any of the incoming bits? A CU upgrade would typically cost in the region of £300-£500, but really depends on area, how many circuits, etc etc.
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londonman

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Re: Lifetime of red/black cables?
Reply #5 - Oct 24^th, 2016, 7:26am

Lec, sounds like you have hit the nail on the head. This is an extract from the surveyors report..

The incoming main appears not to contain an earth back to the grid; it is recommended that the incoming cable is altered to include an earth, so the electrical system can be earth-bonded and fitted with modern circuit-breakers for safety.

The incoming main passes an old main distribution box, with pull-fuses. It is recommended that the fuse boxes are upgraded to RCD boards. Ring mains and local wiring are in modern plastic-sheathed cabling .

No incoming earth? Is that the responsibility of the electric company (the property is on the Northumberland/Cumbrian border.

What sort of price would one be talking about to have the consumer unit replaced? Presumably if wires are too short to reach the MCB's inside it then extra lengths are crimped on ? Just hope no 'borrowed neutrals' !

Do you know anyone up in that neck of the woods ?

TIA

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londonman Trade Member Offline I love YaBB 1G - SP1! Posts: 1666 Total Thanks: 10 For This Post: 0 Malvern United Kingdom Trade: Cabinet Maker	Re: Lifetime of red/black cables? Reply #4 - Oct 10^th, 2016, 1:28pm Thanks for the clarification, Lec. No gas pipes. Water pipes are plastic. No idea what sort of mains connection. Out in the sticks. Underground IIRC.
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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8727 Total Thanks: 96 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Lifetime of red/black cables? Reply #3 - Oct 9^th, 2016, 2:55pm If there is no RCD protection, I would say upgrade to a 17th AMD3 CU. Protective bonding to gas/water services where they enter the building, within 600mm of stop tap/gas meter. 10mm earth cable. At that age, you may not have any bonding, it may solid strand 2.5 or possibly stranded 6mm.
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londonman

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Re: Lifetime of red/black cables?
Reply #2 - Oct 9^th, 2016, 11:36am

Lectrician wrote on Oct 9^th, 2016, 8:15am:

My house is 78. I would not dream of rewiring or being concerned!

An upgrade to bonding and consumer unit would be the main thing, and checking for DIY bodges.

Thanks for the quick reply. Can you expand a little re 'upgrade to bonding'? Re the consumer unit....are you saying replace with a 17th gen one? What happens if the cables are too short to easily do this ?

I can check DIY bodges just fine Grin

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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8727 Total Thanks: 96 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Lifetime of red/black cables? Reply #1 - Oct 9^th, 2016, 8:15am My house is 78. I would not dream of rewiring or being concerned! An upgrade to bonding and consumer unit would be the main thing, and checking for DIY bodges.
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londonman Trade Member Offline I love YaBB 1G - SP1! Posts: 1666 Total Thanks: 10 For This Post: 0 Malvern United Kingdom Trade: Cabinet Maker	Lifetime of red/black cables? Oct 9^th, 2016, 7:32am Looking at buying a house that was totally renovated in 1979 and so will be red/black. Is there a lifetime for these cables (leaving aside things like lying on top of polystyrene (IIRC...that leaches out/in to the insulation or something similar). How does it degrade ? What should I be looking out for ? TIA
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