Does my house need to be rewired...?

[vonsworld]

Hello

My home is 50 years old this year and has never been rewired.

In recent times I've noticed that when similar houses sell in my estate they always rewire them before moving in. I presume that rewiring will have been a recommendation on their survey or maybe even a condition of the mortgage?

Anyway I am sure our wiring is safe, we never have any problems, and so how many years do you think before rewiring becomes a real necessity?

The cables in the house are the modern pvc type, not lead or rubber, and there is no earth on the lighting circuit which I guess was the norm when it was installed in 1968.

I am planning to have the consumer unit upgraded, since at the moment it is the original cartridge fuses, and I expect the electrician can do a safety check at the same time. I know that they can check the effectiveness of the earth connection, but what else are they able to check please?

Thanks for your advice
Robin

 

[ban-all-sheds]

My home is 50 years old this year and has never been rewired.

Except, quite possibly, in a "ship of Theseus" way.

It would be very unusual for absolutely nothing to have been done to any of the wiring in 50 years.

In recent times I've noticed that when similar houses sell in my estate they always rewire them before moving in. I presume that rewiring will have been a recommendation on their survey or maybe even a condition of the mortgage?

CYA comments by "surveyors" about the wiring are common people may decide to just have it done rather than paying out to be told it has to be done. Although "has to be" has been on the wane for some years, it was only a likely outcome for old rubber-insulated wiring.

Also, the requirements people have these days are very different from those of 50 years ago. People want far more sockets, they want metal light switches, they want more than one lighting circuit, they want circuits divided between multiple RC or the use of RCBOs, they want ovens and hobs in different places in the kitchen, they want outdoor lighting and supplies, increasingly more people want hot-tubs, or EV charging points, or some degree of automation or wireless control, or UFH, or (no matter how bonkers) ceilings peppered with an array of small recessed lights.

An essentially 50-year-old electrical installation is likely to be way off the mark for people moving in, and before moving in is the ideal time to have it all replaced. Not because it is flaky, but just because it is no longer fit for purpose.

Anyway I am sure our wiring is safe,

How can you be?

Simply "everything works" is not enough to be sure.

we never have any problems

An analogy I like to make is that I would never have had any problems if unbeknown to me I'd never had working airbags or seat belts in my car.

and so how many years do you think before rewiring becomes a real necessity?

Once into the PVC era, then apart from the period of "green goo" cables, their life is pretty long. What happens in reality is that various mods are done over the years, often these are bodged, and eventually you get to the situation where a complete, or major, rewire is the easiest and cheapest way to fix the backlog of historical issues and implement the new spec which people want.

A genuinely untouched, as-original, 50-year-old installation should be fine, subject to the fact that it's always possible for cables to be damaged by overloads, or non-electrical events.

The cables in the house are the modern pvc type, not lead or rubber, and there is no earth on the lighting circuit which I guess was the norm when it was installed in 1968.

That lack of an earth is quite limiting.

I am planning to have the consumer unit upgraded, since at the moment it is the original cartridge fuses, and I expect the electrician can do a safety check at the same time. I know that they can check the effectiveness of the earth connection, but what else are they able to check please?

Whatever you ask them to.

They ought to do a fair bit of checking before they replace the CU anyway, since afterwards is not the time to find that there's an earth fault which trips an RCD.

 

[sparkwright]

Your house may be older than 1968 - no earth on lighting circuit is pre-1966.

The condition of the wiring may be ok, and as said, you have limited power points, and have any alterations may have been badly done?

Don't rely on the installation being thoroughly checked over just because you are getting a new consumer unit.

The whole installation should be assessed, and anything bad should be put right.

As for the original wiring, I suppose some common sense needs applying as to whether it's worth doing - how long do you expect to live in the house, do you want metal light switches and more sockets, etc.

I wouldn't expect 50 year old pvc wiring to suddenly deteriorate, apart from any green slime which can be present in wiring of this age, as Ban reminded us.

An important factor is if there is an earth bonding cable to the water and gas.

Is this a house or bungalow? Rewiring lights on a bungalow is usually very easy.

 

[Risteard]

No such thing as "earth bonding" sparkwright.

 

[stem]

In 1997, I purchased a circa 1964 built house. It had PVC cables, and the lighting circuit was also without earth. Originally I planned to rewire it from scratch. However, when I started, I found that the original PVC cables appeared extremely tough and the insulation and conductors were in very good condition. Electrical testing confirmed this.

My house was 'as built' and a big clue here is the number of sockets that would have been originally installed. I have a large 3 bed detached house, and as was the norm in the 1960's There was only one single socket in each bedroom, one on the landing, two in the kitchen, one double in the lounge, one in the dining room, and none in the hall or the attached garage. making a grand total of 9 sockets for the whole property. If you have any more than this, they are probably later additions, and as has been said, they may, or may not have been added properly.

After I moved in, the wiring for the existing sockets was left in situ, and it's still there 20 years later. It has not been altered or added to. New circuits were installed as modernisation of each room followed bit by bit to increase the number of sockets (we now have more in the kitchen than in the whole house when we bought it). The gas supply pipe didn't have any bonding, so that was added and the uninsulated, thin, multi strand wire to the water main was upgraded with something that met the regulations at the time. A new consumer unit with MCB's and RCD replaced the wooden fuse box.

The lights were more of a problem. Every light that Mrs Stem liked required an earth connection. As did the metal faced light switches. At the time, very few light fittings, except the naff plastic ceiling rose and pendant variety were double insulated and suitable for circuits without an earth.

I also discovered that when built, the recessed back boxes for the light switches were plastic, but some had been changed, (probably because the plastic threads had been stripped) for metal versions but these had no earth connection as there wasn't an earth wire to connect them to. As a result the lighting circuits were rewired.

So, in the end the property was more or less rewired, apart from the 9 original sockets. If there were to be a next time, would I do the same? Maybe if I was doing DIY as the work was spread over 5 years. But if I was engaging the services of a professional to do it all in one go, I would definitely go for a full rewire from the off.

 

[ericmark]

1966 was when rules changed on earths on lights. So if wired in 1968 then it has never been compliant although I expect the builders will not correct it now.

In the main plastic cables don't degrade, however there were some batches where the plasticizer leached out, normally seen as a green grunge.

The fuses in Wilex fuse boxes can be easy changed for MCB's so if reason for change is the problem changing a fuse, then you don't need to swap the distribution unit for a consumer unit. However fitting RCD protection is not so easy, although I have done it in my own house, it is really not cost effective, and new consumer unit is way to go.

However RCD's can cause problems, one there may be some leakage in the old wiring causing them to trip, and two it means more likely to lose items like freezer if it does trip, three there may be mods like splitting the lighting which have resulted in undetected shared neutrals, so with old wiring one it needs testing before RCD's are installed. Even then on old wiring better to use RCBO's so less is lost if it does trip.

When rewiring floorboards are lifted and decoration messed up, job one remove wall paper as very hard to re-plaster without it showing where done in the future if there was wall paper on the wall, so moving into a house getting the wiring done before any carpets laid or wall painted makes sense. Hence why re-wired before moving in.

I had mother's house done while she was in a rest home, it took a week to rewire, but took me another two weeks to re-plaster and paint walls, and 18 months latter still correcting small faults, mainly my re-plastering, but also where we had not expected a socket would be required. I had a cheap job as in a hurry, had to be finished before mother returned, but if decorating was included looking at £5000 I seem to remember I paid around £2500 for a bare minimum just to make house safe, mother had put an extension lead in a bucket of water because she saw red neon and thought it was on fire, so needed RCD protection.

Father-in-law still has no RCD protection, and since not doing any DIY at 90+ the risk for him at moment is very low, and it would need emergency lighting if RCD's were installed as stairs in centre of house.

His and my house built 1978 I would not dream of a rewire. Swap fuse box for consumer unit yes, but not a re-wire, however the no earth in lights is rather restrictive as to what lights and switches can be used, so maybe you want metal lamps, or switches, even a fluorescent lamp in the kitchen is near impossible to find as a class II fitting, and light switches should have the bungs over the retaining screws, or other method to stop anyone touching screw, could be a blob of silicon sealant.

But without knowing your style of living, and walking around the house, can't really start to advise, really needs an EICR however even that it depends who does it.

 

[seasickstevie]

a fluorescent lamp in the kitchen is near impossible to find as a class II fitting,

Most 'batten' fittings are now LED, and double insulated.

and light switches should have the bungs over the retaining screws, or other method to stop anyone touching screw, could be a blob of silicon sealant.

Wouldn't consider that acceptable. If the box were to become live, you'd likely get a 'tingle' (particularly on the ground floor) off the wall. In fact, if you were to touch a radiator and the wall at the same time, it could be more than a tingle.

 

[Adam_151]

Wouldn't consider that acceptable. If the box were to become live, you'd likely get a 'tingle' (particularly on the ground floor) off the wall. In fact, if you were to touch a radiator and the wall at the same time, it could be more than a tingle.

Not sure I like the plastic caps or bit of silicon (they will be taken out at some point and not replaced), But not sure how much a risk the making the wall live thing is (although of course its theotretically possible). Even pre-66 contactable metal parts were requried to be earthed, the accepted solution in terms of switch plate screws at the time was metal boxes that had nylon lugs for the screws to go into. The accepted retro-fit workaround tends to be nylon plate screws

 

[seasickstevie]

Not seen nylon screws for a very long time. Are they still available?

 

[ban-all-sheds]

https://www.bing.com/search?q=nylon+m3.5+screws

 

[plugwash]

I am planning to have the consumer unit upgraded, since at the moment it is the original cartridge fuses, and I expect the electrician can do a safety check at the same time. I know that they can check the effectiveness of the earth connection, but what else are they able to check please?

They can check the resistance of the insulation at a test voltage (usually 500V). They can check that RCDs if any work. They can inspect visually for problems

What they can't readilly detect is cables that have become brittle but are for the moment still sufficiently intact to keep the conductors apart. They may spot problems with circuit topopoly but in general only spot checks are done, so the odd multi-socket spur could easilly slip through. Similar story for undersized cable, if they see if they can report it but they probablly won't see every inch of the installation.

Rubber cables were known for going brittle over time. Plastic cables seem to be far less prone to it.

When I moved into my present place (built late 1950s, probbally never rewired) I had it almost completely rewired as the bulk of the wiring turned out to be a mixture of old rubber and horrible bodges. Interestly the old rubber seemed to be in surprisingly good condition.

Your place is new enough to have hopefully avoided rubber cables but what about the horrible bodges? has the wiring been extended over the years? if so who did it? did they know what they were doing? did they cut corners?