Build Basics: Electrics

Wiring up your new home is a tightly regulated project - discover the basics with our guide
by Chris Bates
26th November 2012

Energising a new house is becoming ever more complicated. Gone are the days of simply running a few mains cables, a phone line, TV aerial and wiring up the doorbell. Now, self builders are kitting their homes out with security systems, loft circuits, high-tech networking and everything in between. Regulations have moved on, too, demanding the addition of smoke detectors, setting ‘special locations’ such as kitchens and bathrooms, and requiring you to notify building control before embarking on a project. So what’s the best way to tackle new build electrics?

Finding an electrician

As always, recommendations are the way forward – ask relatives, friends, neighbours and self builders in your area for advice. You can also track down electrical contractors in your area using the websites of trade bodies such as NICEIC, or even ask your plasterer or plumber for a recommendation, as electricians work alongside these trades.

One of the key questions to ask is whether a prospective contractor is registered with a Part P competent persons scheme (or whether the firm they work for offers this service). Most local authorities encourage self builders to engage this type of contractor, as they hold the appropriate qualifications, knowledge and experience to carry out inspection and testing procedures according to BS 7671 and issue an electrical installation certificate. On top of that, they can also issue a Building Regulations compliance certificate (a copy of which should be sent to your building control body).

Another common choice is to use an electrician who – although not signed up to a Part P competent person self-certification scheme – is registered with a trade body, such as NICEIC, ECA or NAPIT. Such contractors should be qualified to design, install, test and issue certification to BS 7671.

Usually, building control will accept this certificate as evidence that the work complies with Part P. Nevertheless, you’ll need to notify building control of your proposed installation before work commences and pay a notification fee (around £120 on top of the normal building notice charge).

You may also be required to submit to additional inspections and tests by building control. Often, the extra costs negate the savings of opting for a contractor who hasn’t gone through a Part P self-certification scheme.

Both routes are viable, and ultimately you should base your choice of electrician on the quality of their previous work, your relationship with them and their understanding of your project.

What will it cost?

Prices vary significantly depending on complexity and specification. A quick look at the cost breakdowns for Build It readers’ projects shows that a basic electrical installation can be completed for as little as £3,000. But for homes kitted out with top-of-the-range automation systems, you might be looking at £30,000 or more.

As a guide, electricians who work on a day rate will typically charge around £150. But for a self build you’ll usually be quoted a supply and fix price for the entire job (or at least the first fix). It’s a good idea to arrange payment at key stages of the project – for example on completion of first and second fix, and after certification is achieved – especially if you’re financing your build with a stage payment mortgage.

One of the advantages of building from scratch is that you can avoid the problems most homeowners have of a lack of sockets and light fittings – fitting double rather than a single sockets throughout will barely register on the cost scale, for example.

You can go some way towards future-proofing your home by having your electrician run CAT 5e or CAT 6 cabling alongside the main wiring – perhaps following TV or phone line cables. You may even be able to convince the contractor to run this extra cable at cost – which could be as low as £200-£300 – with no extra labour charge. Paying that money now will prove worthwhile should you decide to add smart home technology later on, as retrofitting can be expensive (unless you’ve invested in conduits).

What services will my electrician provide?

Your sparky will work with you to interpret your house design and requirements into a safe electrical system that complies with regulations, following the technical rules laid out in BS 7671.

Factors such as the number of rooms, socket and light outlet requirements, TV and telephone points, cookers, electric underfloor heating and renewable energy systems will all come into play. As well as affecting considerations such as cable and backbox locations and specifications, these factors will ultimately also impact on your choice of consumer unit (formerly known as the fuse box).

First fix electrical work is all about preparation. At this stage, your contractor will put in the bare bones of your system – much of which will be hidden by the end of the project. Your sparky’s first task may be to install a temporary consumer unit to provide power to the site, after which they’ll move on to installing the earth rod, running carcass wiring and fitting backboxes. If you’ve notified building control of the project, an inspection will usually be necessary at this point.

Your electrician will work closely with other trades. He’ll need to cross bond and earth the pipework your plumber installs, for example, as well as communicate with plasterers and dryliners to ensure back boxes can be installed in the correct locations, and that holes are left in ceilings for light fittings where necessary.

Similarly, the IEE wiring regs require your sparky to run cables buried in walls either vertically or horizontally from outlets, within a 150mm tolerance, which makes life a lot easier for following trades.

Extras, such as renewable electricity sources and electric underfloor heating, will usually be installed by the company you buy them from, as most have a suitably-qualified electrician on their books. If you want to take advantage of Feed-in Tariffs for photovoltaic panels, for example, your set-up must have been fitted by an MCS accredited installer.

Second fix occurs after the plastering is complete, and primarily consists of wiring up and fixing visible items, such as faceplates, light fittings, security systems, cooking equipment. The sparky will also install the permanent consumer unit, test the system and be present at the firing and testing of the boiler.

What can I do myself?

On a practical level, most self builders are best off contracting the work out. However, technically, Part P allows you to carry out a great deal of electrical work on a DIY basis – from carcass wiring to fitting sockets and lighting. By taking this route, you’ll be in a similar position to an electrician who isn’t registered with either a competent persons scheme or a recognised trade body to work to BS 7671.

You’ll need to go through the process of notifying building control prior to work commencing and submitting to inspections – usually by both building control and a registered electrician (which somewhat negates the point of DIY). So you’ll still be paying the additional Part P notification fee, and may need to shell out for inspection and testing costs, too. Once the work has been completed and tested for compliance to the required standards, a Building Regulations completion certificate will be issued.

Beyond complying with regulations, there area some key questions to ask yourself before you embark on DIY electrical work. What work do you feel competent to complete, for example? Is the money you’ll save worth the extra time you’ll undoubtedly be adding to your build? If you lack experience with electrics on a construction site, could this lead to miscommunication with other trades and result in costly mistakes?

It’s worth bearing in mind, too, that there’s little point in mixing DIY with the use of registered electrician for jobs you’re not confident about. Unless they physically oversee you doing the work, it’s unlikely they’ll be willing to risk their reputation (or worse) by certifying the project as fully BS 7671 / Part P compliant.

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