House Rewire

[MisterDrew]

Hello,

I am considering buying a property that I have been told was rewired in 1994/1995 and he fuse box looks relatively current.

Are the specs of fuse boxes upto current loads/laws required from back then or would it be best to rewire due to that age of box?

Thanks
Drew

 

[EFLImpudence]

Are the specs of fuse boxes upto current loads/laws required from back then or would it be best to rewire due to that age of box?

Your question is somewhat confusing.

Rewiring and/or updating the consumer unit are separate issues.

There is a difference between between being 'up to current specs.' which may include modern devices and being unsatisfactory or unsafe.
The regulations are not retrospective.

Commission an "Electrical Installation Condition Report" from a reputable electrician.

 

[Taylortwocities]

If the wiring was renewed in 1994/5 then the cabling itself will still be of serviceable condition. It will have been done in PVC cabling and that has a useful life of up to 50 years.

The rewire should have been accompanied with an Electrical Installation Certificate. Ask for a copy. This will show the testresults of teh installation at the time. There's no telling what may have been added/changed over the ensuing 20 years and an EICR is the only way of getting a definitive report on the health of the installation now.

The consumer unit will have been installed to meet the regulations at the time. As EFLI says, these regs are not retrospective and there's no REQUIREMENT to keep up to the latest regs unless new circuits or other work is carried out.

 

[JohnW2]

The consumer unit will have been installed to meet the regulations at the time. As EFLI says, these regs are not retrospective and there's no REQUIREMENT to keep up to the latest regs unless new circuits or other work is carried out.

Indeed. Just to make sure that there is no uncertainty about what you saying, even if new circuits are installed, or other new work is carried out, it is only those new circuits or new works which are required to meet current regulations - there is still no requirement, per se, for other parts of the installation (e.g. the CU) to be brought up to compliance with current regs.

Kind Regards, John

 

[ericmark]

1994/5 was a time when as standard earth leakage tips were only fitted to TT installations and even then it was likely 100ma rather than the 30ma used today. Other than that very little has changed. In the main fitting a new consumer unit (was called fuse box but now rarely contain fuses so new name.) will bring you up to the same spec as a modern house.

However it is not required. The main reason to up-grade is in order to add new circuits. Although one can add a single socket without much of a problem because of the RCD requirement adding 10 sockets it would likely be cheaper to swap consumer unit first.

As to if you need RCD protection well that depends on your family. My Mother and Father-in-law are extremely unlikely to do anything which would mean a RCD would offer any extra protection than the 1952 and 1980 wiring in the two houses.

However for me back in 1994/5 with a young son of 13 taking an interest in Amateur Radio fitting of RCD's was a very necessary precaution. So with no children and non into DIY then no reason to fit RCD protection the risks are very low. But either into DIY or with children who may fiddle then yes. As a 12 year old I did stick my fingers in a bulb holder to feel what was in it and I did get a shock. Clearly it did not kill me but it could have done seems dad had removed bulb when switch stuck on. The RCD will not stop you getting a shock, but it will reduce the time you can get the shock for to 40ms.

Even with a RCD electric can still kill but the likely hood is reduced. There are exceptions but in the main an adult who does not fiddle should not need RCD protection. As I say there are exceptions there has been a report in last few months on how a plaster caused a fault which combined with poor electrical testing caused a death which would not have happened had a RCD been fitted but fortunately these cases are very rare.

As other have said one does not know what DIY work has been done, but one would hope any faults with an installation installed in 1994/5 will have been found and corrected a long time ago so unless there has been DIY work likely there is very little extra risk by not having RCD protection.

 

[winston1]

As a 12 year old I did stick my fingers in a bulb holder to feel what was in it and I did get a shock. Clearly it did not kill me but it could have done seems dad had removed bulb when switch stuck on. The RCD will not stop you getting a shock, but it will reduce the time you can get the shock for to 40ms.

A RCD will not trip if you stick your fingers into a bulb holder as you are only contacting live and neutral. The shock will last until you remove your fingers.

 

[phatboy]

A RCD will not trip if you stick your fingers into a bulb holder as you are only contacting live and neutral. The shock will last until you remove your fingers.

Are you sure about that?

 

[JohnW2]

A RCD will not trip if you stick your fingers into a bulb holder as you are only contacting live and neutral. The shock will last until you remove your fingers.

Are you sure about that?

Provided it's not a lampholder with touchable earthed metal parts, winston is correct. Lampholders are commonly plastic with no exposed earthed metal parts. Indeed, the flexes going to plastic pendant lampholders them are not uncommonly 2-core.

In the absence of a path to earth, an RCD could not possibly trip - it could not tell that the current going through the person (from L to N) was not just an 'ordinary' current going through a legitimate load.

Kind Regards, John

 

[RF Lighting]

L>N is ONE of the paths the current will flow

 

[JohnW2]

L>N is ONE of the paths the current will flow

I was responding to:

"... if you stick your fingers into a bulb holder as you are only contacting live and neutral..."

If one contacted only L & N, there obviously would be no path other than L>N through which current could flow. However, if one also contacted something other than just 'live and neutral' (e.g. a nearby earthed pipe), then, yes, the situation could obviously change.

Kind Regards, John

 

[RF Lighting]

Unless you're levitating, there's virtually always a second path.

 

[JohnW2]

Unless you're levitating, there's virtually always a second path.

Literally true, but within a building (with a roof!), and particularly if one is wearing shoes, it's very unlikely that any 'incidental' path to earth would have an impedance even remotely low enough for 30 mA to flow through it with a maximum driving pd of ~230V.

Indeed, whilst I'm not going to fully describe the 'experiment' in question, I'm sure you know that if you were wearing shoes and standing on the floor of a house (or a stepladder or whatever within the house) and you did **** with your finger, you would very probably not even 'feel anything', let alone trip an RCD!

Kind Regards, John

 

[ericmark]

From memory it was a long time ago there was a path to earth as I only touched one pin at a time. Sitting on a stool which was on a quarry tiled floor not a clue as to materials the stool was made of but main thing I never repeated the investigation.
Personally I think any ELCB be it v or c and latter 30ma or 100ma would have tripped. But early 1960's ELCB's were rare not sure when the ELCB-v started to be used but at that point I had not seen one.
Many years latter when I came to work on the house electrics I found no earth. There was a steel earth rod but I think this was for the party line phone not house electrics.
But at time of getting the shock water supply would have been metal and would have been earth for house. At that time no gas. As with many houses the water supply was changed to plastic as was the street gas main.
Now TN-C-S supply. However when I took over the job of doing a wet room the electrician had failed to notice there was no earth.

 

[JohnD]

"I have been told was rewired in 1994/1995 "

this may well be untrue. Even if true, it may not have been done properly. So start with an inspection.

 

[JohnW2]

From memory it was a long time ago there was a path to earth as I only touched one pin at a time. Sitting on a stool which was on a quarry tiled floor not a clue as to materials the stool was made of but main thing I never repeated the investigation.

I suppose that if it was a metal stool sitting on damp quarry tiles laid directly onto soil, you would be 'changing the probabilities' (and 'sitting on a stool evades the usual protection of shoes), but I'm still rather surprised.

If you try measuring the IR between any common flooring, floor covering or wall and earth in any 'normal' house, I would be extremely surprised if you get anything other than 'very high' readings.

However, don't forget that in order to feel an electric shock, you only need around 1 mA, hence a ≤230 kΩ path to earth (which is pretty high) - although you would be incredibly unlucky (e.g. pre-existing serious heart disease) for that to do you any harm!

Kind Regards, John