Rewiring Fun. Estimating the Age of Electrics

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Hi, I'm about to take leap of faith buying a property which I've not been able to see properly. It has a been extended a couple of times since it was built in 1970 and the current owner has no idea about the history of electrics, no certificates of any kind and doesn't want any visiting electricians. They've not touched it since they moved in 2009.

The consumer unit will need moving to the opposite room at about 20ft.

Would appreciate an experienced eye guesstimating the age of the board? I'm going to guess 1990's given this was the last extension? We're planning to knock a few walls about and knowing the age of the install might tell me whether I'm likely looking at a complete rewire or just extending the cables!

Any guidance appreciated. Thanks.
 

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Are you competent to remove the cover of that board?

If we could see the colors of the cores inside, we might have a better idea of its age.

Perhaps also some pictures of the electrical accessories.... maybe some light fittings too? If there are ceiling roses, unscrew the cover & let us see inside?

Obviously all the above with the power off :)

Moving the board 20ft could be a whole heap of pain.... the tails (the thick cables between the meter & the consumer unit) can only be upto 3m long before additional protection is needed..........
 
If you're planning on doing internal 'works' why not work on the basis that it needs a complete rewire - then you at least know it's all good - and you'll have tickets to prove it. The CU clearly doesn't comply with current requirements and fitting a new CU elsewhere will entail extensive works so you might as well bite the bullet and do a 'proper' job.
 
Good news:
The current regs require a non-flammable consumer unit. That Contactum unit is metal! But that’s the only plus.

Bad news1. The front door panel of the CU is missing, so it no longer complies with regs.
Bad news2. The regs more or less now require all circuits to be RCD protected. There is no RCD protection on that board.

Conclusion: you’ll need to Chuck that board away and have a compliant one installed. Go for an all RCBO board.

Note the above input regarding the allowable distance/length of meter tails. Changing the CU is notifiable work, so you’ll need a registered and competent electrician on the case anyways.
 
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If i'm reading the BSOL site correctly it seems BS60439-3 was introduced in 1991, so I don't think it can be any older than that. The 16th edition of the IEE regs was published in 1991 and IIRC it started to bring in requirements for RCD protection (which is absent in your CU), though I'm not sure what overlap period the IEE suggested.

So I think it's most likely that CU was installed in the early 1990s, though it could have been installed later by someone who wasn't keeping up to date on the latest regs.

A new CU doesn't mean the property was rewired though, it's common to fit new CUs to existing wiring and I suspect much of the wiring in the house is probablly still original

Original wiring is not necessarily a problem though, my understanding is that by the 1970s they had largely switched to PVC insulation which doesn't degrade in the way that rubber does, though some batches had issues with the plasticiser.
 
Original wiring is not necessarily a problem though, my understanding is that by the 1970s they had largely switched to PVC insulation which doesn't degrade in the way that rubber does, though some batches had issues with the plasticiser.
True. But houses of that age usually did not have earthed lighting circuits, so rewire of lighting may be required. we may be able to guess is we could see inside the CU. The only real way is to have a report carried out on the installation.
 
Are you competent to remove the cover of that board?

If we could see the colors of the cores inside, we might have a better idea of its age.

Perhaps also some pictures of the electrical accessories.... maybe some light fittings too? If there are ceiling roses, unscrew the cover & let us see inside?

Obviously all the above with the power off :)

Moving the board 20ft could be a whole heap of pain.... the tails (the thick cables between the meter & the consumer unit) can only be upto 3m long before additional protection is needed..........

Thanks that's interesting re: the 3m requirement. The meter is actually 5+ meters away in a nearby garage (an extension 10 years after the property was built). Photo attached.
Sadly the current owners are refusing any more visitors now so I'm having to go with what I have with photos. Thanks for your help.
 

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If you're planning on doing internal 'works' why not work on the basis that it needs a complete rewire - then you at least know it's all good - and you'll have tickets to prove it. The CU clearly doesn't comply with current requirements and fitting a new CU elsewhere will entail extensive works so you might as well bite the bullet and do a 'proper' job.

Thanks very much. Yes I'm starting to err that way! It's a 4 bed detached with ~10 rooms. I'm led to believe a rewire is probably in the realm of 4-7k worst case. Having to take a leap of faith given they're pushing back on further viewings!
 
Good news:
The current regs require a non-flammable consumer unit. That Contactum unit is metal! But that’s the only plus.

Bad news1. The front door panel of the CU is missing, so it no longer complies with regs.
Bad news2. The regs more or less now require all circuits to be RCD protected. There is no RCD protection on that board.

Conclusion: you’ll need to Chuck that board away and have a compliant one installed. Go for an all RCBO board.

Note the above input regarding the allowable distance/length of meter tails. Changing the CU is notifiable work, so you’ll need a registered and competent electrician on the case anyways.

Thanks, much appreciated and v. helpful.
 
If i'm reading the BSOL site correctly it seems BS60439-3 was introduced in 1991, so I don't think it can be any older than that. The 16th edition of the IEE regs was published in 1991 and IIRC it started to bring in requirements for RCD protection (which is absent in your CU), though I'm not sure what overlap period the IEE suggested.

So I think it's most likely that CU was installed in the early 1990s, though it could have been installed later by someone who wasn't keeping up to date on the latest regs.

A new CU doesn't mean the property was rewired though, it's common to fit new CUs to existing wiring and I suspect much of the wiring in the house is probablly still original

Original wiring is not necessarily a problem though, my understanding is that by the 1970s they had largely switched to PVC insulation which doesn't degrade in the way that rubber does, though some batches had issues with the plasticiser.

Extremely helpful, thank you! Couldn't believe it was original and that confirms it's probably 90's then. Helpful to know it is probably PVC too, thanks.
 
Bad news1. The front door panel of the CU is missing, so it no longer complies with regs.
I'm not aware of any reg (in BS7671) which explicitly requires a front panel - are you perhaps referring to what is required by a product Standard?

Kind Regards, John
 
@B Wilde thank you for the garage photo. Must revealing.

You seem to have an RCD installed there. While this will provide RCD protection for the whole installation, it is very bad practice to have just one RCD. One small fault could trip the RCD and this would disconnect the whole house. This goes against the requirement for separation of circuits. No single point of failure.

To the right hand side is a switch fuse feeding what looks like a SWA cable that probably feeds the house consumer unit. This combination allows the distance from the meter to the CU to be greater than 3 meters.
 

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