Is this par for the course?

[Stevos]

Just moved house (early 80s built IIRC), and replacing some of the lights, switches etc, but hoping not to have to do any rewiring. I'm a novice at this so I'm not sure if this is the sort of thing to expect. (though I know a small amount of electrical theory, I haven't messed with much real world wiring before.)

It seems the previous owners/fitters had a terrible fear of earth connections, and were working hard to make sure they didn't make contact with any metal surfaces. This seems to have been enforced in all the metal switch plates, metal light fittings, and probably in the metal socket plates too (I haven't had time to check these yet).

After removing a kitchen light, I found it connected by thin choc block to less than an inch of wire pair coming out of a ball of mastic and plaster partly blocking a hole in the ceiling. One of the strands of each wire had been cut or broken off - maybe to make it easier to bend into the choc block.

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• Stevos
• 21 Feb 2014
• 1

There was an earth connector on the metal body of the light fixing, but no visible earth wire. I assumed it was just old wiring without an earth, and tried to reconnect the choc block to put things back, at which point the exposed wire sheared off at the sleeving from where it had been overly stressed.

On further inspection, poking, prodding and pulling out chunks of mastic and ceiling, I found that there was in fact plenty of cable up there, but that someone had intentionally fixed it in to be that short.

There was also a bit of black electrical tape wound around the end of the insulation, which contained the earth wire, bent back along the cable.

Eventually got this all hooked up, earth connected, and working, but I probably should stay away from electrics because this sort of thing makes me wonder what's happening with the bits I can't see.

Now I'm wondering if the earth wire is even connected to anything on the other end. Maybe I'm going around fixing up earth wires which just go into a bundle of electrical tape somewhere in the walls

Oh and I just found a socket with 3 doubles spurred off it which I'm trying not to think about too much. I'm slightly scared I'll find that all the socket earth pins throughout the house have been (safely ) isolated from earth too...

The other thing I'm trying not to think too hard about is the oven tripping out at random times although maybe that's encouraging though, as it means some safety features work.

 

[slippyr4]

It wouldn't cost too much to get someone in to do a PIR, and then you will know where it's deficient.

 

[slippyr4]

The other thing I'm trying not to think too hard about is the oven tripping out at random times although maybe that's encouraging though, as it means some safety features work

It also means there's a fault.

 

[Stevos]

I think I'm going to need a qualified electrician at this point. Or a cup of something medicinal.

Today the fridge stopped working. I checked the socket (which hadn't been touched for over a week when it was switched on with the new fridge). Turns out the live wire had come loose and was flapping around inside the switch casing. Fortunately in this case it was a plastic socket with a correctly connected earth.

Thinking that this sort of thing might be bad when combined with metal switches and socket plates and inconsistent approach to earthing, I embarked on a campaign to replace them with plastic plates and check everything was correctly and tightly connected.

On the second socket after disconnecting it I found this:

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• Stevos
• 21 Feb 2014
• 1

Spot the great condition of that insulation. Two live wires have been stripped in the middle (forensic examination suggests a Stanley knife), and to add further excitement, a neutral has been squashed against a screw thread until the insulation was crushed.

I wonder if the previous owners are trying to kill me.

 

[PrenticeBoyofDerry]

I think that you really require a full inspection and test of the installation you have inherited. This would be done via an electrical installation report. It was all to common in 40 plus years ago that the circuit protective conductors on lighting circuits was not used or non-existent. But a property from the 80s I would expect the connection to be made. If you have metallic fittings and be the evidence you have submitted I would be fearful that there could be a potential danger, so I suggest you act quickly!

 

[Mikefromlondon]

It seems like your complete house wiring needs a serious attention, check each and every socket, ceiling rose, and all wiring where possible, if found out to be dangerous you might consider rewiring by an expert and get a few quotes, shocking really when you see those knife nicks in the insulation of red live carrying wires.

 

[Stevos]

Thanks for the advice, I agree it needs inspection and probably rewiring (which I almost certainly can't afford.)

In the immediate term I'm repairing and replacing the unsafe bits I find, with a particular emphasis on the metal switches etc.

That particular socket, I've cut back the stripped wires to remove the obviously dangerous parts, joined up (Hopefully safely) with 15A choc block and will cover it with a blanking plate as soon as I have one. I don't think there's enough wire to safely connect a socket there.

Half of me thinks this is terrible, and half suspects many houses are probably just like this if you look what's underneath.

I'm hoping that the maniac with the Stanley knife won't have got at the cables inside the walls and ceilings, and it's just the visible cables that have been damaged.

 

[Mikefromlondon]

I think you mentioned your cooker keeps tripping, but not sure if you meant an RCD or an MCB, and if it is MCB, this would trip if there were severe overloading or intermittent shorting.

If you haven't got an RCD fitted then make that as an important safety device to protect your unearthed sockets. It is not a substitute for bad earths, but anything becoming live it can trip an RCD.

 

[phatboy]

A house that age shouldn't need a re-wire, but if Mr Bodger has been at it then its worth getting someone in to go through every switch and socket and check them out. Also remove any dodgy spurs and of course check for earth continuity!!

You say the oven is tripping - is this is the Consumer Unit? If so it sounds as though that may have been replaced, or at least had MCB's installed.

What you have found is a cause for concern, but I would say it is fixable without a complete re-wire for sure.

 

[Mikefromlondon]

as for an electric cooker/oven if not in regular use, the heating elements can acquire moisture and trip the RCD which becomes a pain, regular use keeps the moisture out, so on my installation i had feed the cooker without the RCD protection as long as you have a good strong erathing to it, this should protect against any leakage currents from the elements when cooker is brought into use. It must be earthed proeprly and if in any doubt run a seperate earthing lead directly to the consumer unit for your added safety.

 

[flameport]

Just moved house (early 80s built IIRC)

The solid green sleeving on the CPC (earth) suggests your house is much older - early 1970s or late 1960s.

 

[maltaron]

It looks like those cables are old 3029 and 7029, somebody at some stage has used old cables or the house is older than stated.

 

[Stevos]

I may have mixed up dates, they were on a document somewhere but I've looked at too many documents recently.

I haven't quite got to the bottom of the oven situation yet, as I haven't had time.

The consumer unit is a crabtree starbreaker. There's a central Switch marked "RCCB split load 63A 30mA" which trips out.

There's also a set of MCB 32 switches marked "RCD protected circuits". the one marked cooker is not tripping. Its possible these are mis labeled.

 

[Stevos]

The switch that trips out when using the oven is the central main RCCB, not the cooker switch

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• Stevos
• 22 Feb 2014
• 1

 

[SimonH2]

Two live wires have been stripped in the middle

I'd say that looks more like "clumsy" stripping of the outer sheath to me, rather than deliberate stripping. From your description it sounds like there have been some BIY additions to the system, and the different types of cable (along with the poor workmanship) would support that.

a neutral has been squashed against a screw thread until the insulation was crushed.

Not at all uncommon. Prior to the use of RCDs this would generally go unnoticed - but where there's an RCD it will trip it once a load is applied.

The consumer unit is a crabtree starbreaker. There's a central Switch marked "RCCB split load 63A 30mA" which trips out.

That's the Residual Current Device (aka Earth Leakage breaker). It trips when there is earth leakage*, which as pointed out could just be a bit of damp in the elements. The two breakers labelled 32A are MCBs and act on current only - ie if the circuit is overloaded or has a short. The RCD is serving both the cooker and sockets - so it may not be just the cooker, there may be some leakage in the socket circuit as well.

* The technical bit, it puts the live and neutral currents through a small transformer - if they match exactly then the output from the transformer is zero (it's accurately sensing the difference between them), but if there is any difference then this shows up in the output and trips the breaker.


But at least you a) care, and b) have enough nouse to ask questions about it. That's most of the hard work taken care of.
As others have said, it probably doesn't need all that much work to put right, but really you need some specialist tools which aren't generally worth having for DIY use. As a minimum you need a conductance tester that can accurately measure low resistances (fraction of an ohm) so you can confirm that a) all the points (sockets, switches, lights) have an earth and b) all the current carrying cables are intact (and in particular, that the ring is complete). A professional spark will have a multi function tester that will do this, and insulation resistance tests at 500V, and test the RCD for tripping sensitivity and speed.

Since you appear to have a fair clue, it might be worth fixing the obvious faults - especially connecting the earths in all the cables - and then get someone in to do an EICR when they can confirm that you've not missed one. Point out the problems you've had as it will influence how thoroughly they test (it's normal to test a sample of the outlets).