Note: this answer assumes the house you are buying is in the UK
Hello, who do I ask to determine if a house needs a rewire? Can I just get a few local electricians out to check the electrics in the house and ask for their opinion?
There are some installations where the need for a rewire or at least major remedial works is obvious from a quick visual inspection.
It would however be a brave electrician who said a property *doesn't* need a rewire based on just a quick visual inspection.
Or will an EICR tell me if the house needs a rewire?
A competently executed EICR should enumerate the safety deficiencies the inspector has discovered in the electrical installation.
No inspection is perfect, even a competently executed EICR cannot be guaranteed to find every defect. The defects are coded by the inspector, there is industry guidance on coding but ultimately it's down to the inspector to assess the risk of any particular defect.
C1 - ‘Danger present’, this is issues that need to be addressed immediately. Things like exposed live conductors.
C2 - 'Potentially dangerous' this is mostly issues that are one step away from becoming dangerous. Exposed conductors with only basic insulation. problems with the earthing/bonding system, degraring insulation and so-on. Industry guidance also places lack of RCD protection in certain higher-risk scenarios and socket outlets too close to baths and showers in this category, though i'm sure some electricans would disagree with them..
C3 - 'Improvement recommended', lack of RCD protection in lower-risk scenarios, various nitpicks about labelling and so-on.
After an inspection you would then need to figure out which defects are going to be addressed and how. If you are renting out the property you are legally required to address C1 and C2 defects, if it's your own home you aren't legally required to address anything.
"needs a rewire" isn't nessacerally black and white. There are some properties that definitely need rewiring but there are others that could be remediated but it's questionable whether a rewire is the better option.
Broadly speaking there are a few reasons for rewiring.
1. Old rubber cable, old rubber can go hard and crumbly. It's insidious because it can work and test fine as long as it's not disturbed but then crack or even disintegrate when someone tries to work on it. For this reason trade organisations recommend that any interference with rubber wiring is kept to an absolute minimum until the property can be rewired.
2. Lack of earths on lighting circuits. The IEE wiring regs changed to require an earth on lighting in 1966, though whether everyone immediately started following them is another matter. Doing any kind of modification work on circuits without an earth can be very awkward.
3. Defective cable, plastic insulation generally lasts a bloody long time (long enough that we don't really know how long it will last because it hasn't been in use long enough) but not all cable is created equal and there have been some cables where the plasticiser leeches out making a bloody mess and potentially making the cable brittle.
4. Damaged cable, for example if there has been a large-scale rodent infestation or a fire or something similar.
5. Horrible bodges, afaict most installations were initially installed in a competent manner. IIRC many electricity boards would insist on an inspection before they would connect a house, but over the years what people want out of their electrical installations has changed and people have modified their installations to suit. Sometimes competently, sometimes not so competently.
6. The installation simply isn't what you want. There comes a point when you look at the list of things you want to change about an installation and decide it would be easier to start again.
