Electrical Musings.

[MarkFish]

The house was built in 1960. Neighbours in similar houses have found their wiring 'crumbled' when disturbed.

Now, the last thing I want to do is disturb my wiring but the house is currently a building site with no carpets down so if we were ever going to rewire the entire place access will never be better. However I thinking that totally rewiring would require a fair bit of tearing wires out from behind plaster?

I figure I need more information. How do I figure out if the wiring is still good?

Will an earth leakage test tell me everything I need to know?

What the least destructive way to work out if my wiring's good?

Am I naive thinking that if insulation broke down on a pair of wires there would be a good chance the fuse would go before a fire started?

 

[JohnW2]

The house was built in 1960. Neighbours in similar houses have found their wiring 'crumbled' when disturbed....Will an earth leakage test tell me everything I need to know?

No

The What the least destructive way to work out if my wiring's good?

In terms of 'crumbling insuation' insulation resistance tests would be a good start. However, given your concrens, you really should get an electrician to do a proper inspection/test of your whole electrical installation.

Am I naive thinking that if insulation broke down on a pair of wires there would be a good chance the fuse would go before a fire started?

Yes,a bit naive. A fuse may blow, but .... for example, a 30A fuse may well allow up to 60A to flow for appreciable periods of time, potentially plenty long enough for a fire to start.

Kind Regards, John.

 

[MarkFish]

Many thanks for taking the time to provide such a useful reply, JohnW.

In terms of 'crumbling insuation' insulation resistance tests would be a good start.

Thanks.

This?
http://www.tlc-direct.co.uk/Book/8.5.1.htm

Yes,a bit naive. A fuse may blow, but .... for example, a 30A fuse may well allow up to 60A to flow for appreciable periods of time, potentially plenty long enough for a fire to start.

Ta.

I'm looking at the wire coming into the fuse box and the wires behind a couple of random plug socket. Admittedly they're the old "red and black" wires but they don't look like they're falling apart and appear to be made of modern materials. Not the old rubber jobbies. Was insulation in the 60's inherently "crumbly"? Is there some kind of lifetime specified for different wire types at different times over the years?

Yes, a qualified electrician will looking at it. (I need a new consumer unit and RCD anyway.) However, I want to clearly understand what he's likely to be doing, and what good practice dictates he should be doing.

 

[Adam_151]

Wiring in the 1960's was some of a cross over between plasticy early PVC stuff and VIR (rubber). You even got cables that had VIR core insulation and were PVC sheaved. No earth to lights was quite common.

http://www.talk.electricianforum.co.uk/your-pictures/91-bang-old-rubber-cables.html
Link above is to another forum showing pcitures taken by a guy who attended a property where VIR had failed under the plaster

 

[JohnW2]

Many thanks for taking the time to provide such a useful reply, JohnW.

In terms of 'crumbling insuation' insulation resistance tests would be a good start.

Thanks. This? http://www.tlc-direct.co.uk/Book/8.5.1.htm[/QUOTE]
Yep, that's it.

I'm looking at the wire coming into the fuse box and the wires behind a couple of random plug socket. Admittedly they're the old "red and black" wires but they don't look like they're falling apart and appear to be made of modern materials. Not the old rubber jobbies. Was insulation in the 60's inherently "crumbly"? Is there some kind of lifetime specified for different wire types at different times over the years?

The old colours are not an issue (that didn't change until around 2004). If the cable is PVC insulated and PVC sheathed, it's quite probably still OK - as you imply, it's the earlier rubber stuff that does/did the crumbling. I don't think anyone really knows how long PVC cables 'last', but there's an awful lot of it from the 60s/70s still out there which still appears fine.

Yes, a qualified electrician will looking at it. (I need a new consumer unit and RCD anyway.) However, I want to clearly understand what he's likely to be doing, and what good practice dictates he should be doing.

I think you really should ask for a full inspection/testing and provision of a full report (and recommendations) - until recently called a 'PIR' (Periodic Inspection Report) but now correctly called an 'EICR' (Electrical Installation Condition Report). That would entail inspecting and testing everything (at least, everything accessible) and would give you a good idea of how safe your installation is, and what is required. If the wiring tests OK, there's no reason why installing a new CU (with RCDs etc.) cannot be done with the existing wiring. 'Cowboys', of course, would tell you that you needed a 'complete rewire' (and then probably do it badly!) so it's important to try to find an electrician you can trust (ideally 'recommended').

Kind Regards, John.

 

[Stoday]

Your wiring's 50 years old, if you can get away without rewiring now, the need will crop up in the not too distant future.

The house would very infrequently be like a building site. Probably you'll have to rewire before it is again, so the rewiring will be far more disruptive.

Take advantage of the current situation and get it rewired now.

 

[OwainDIYer]

Even if the wiring is in perfect as-installed condition, the number of sockets is going to be woefully inadequate, not to mention all the other thing syou might want cables for:

- wall lights
- tv / sky
- intruder alarm
- smoke alarms
- cooker points
- electric shower
- dual immersion water heaters
- surround sound
- phone and computer network
- outside lights
- entry phone

etc

 

[NewOrder]

There is a good chance that the wiring will need work even if the cables are in good condition before a spark can sign of a new consumer unit so just get checked, the lighting main almost certainly won't be earthed either.

There would be nothing worse than doing all the decorating now and then to find you need to rip it all out again