Do electric rooflights need an electrician?
Usually yes, for part of the work. The rooflight itself is fitted by the rooflight installer, and the low voltage connection at the head of the unit is part of that. The mains side, meaning anything at 230V feeding a transformer or a control unit, is electrical work under Part P of the Building Regulations in England and belongs to an electrician who can test it and issue the paperwork.
The exception is a solar powered unit, which has no mains connection at all. Everything else on the subject sits on electric rooflight installation.
Where extra-low voltage ends and mains begins
Almost all domestic rooflight actuators run at 24V direct current. That is extra-low voltage, it is not notifiable, and terminating it at the head of the unit is part of fitting the rooflight.
The dividing line is the transformer or control unit. On one side of it there is a 230V supply that has to comply with BS 7671 and be tested. On the other side there is a thin low voltage cable running to the sash. Understanding which side a given piece of work sits on removes most of the confusion, because the parts people worry about, the motor and the controls, are the parts that are not mains at all.
Part P, new circuits and fused spurs
Part P covers electrical safety in dwellings. In England, running a new circuit from the consumer unit is notifiable work and has to be certified, either by an electrician registered under a self-certification scheme or through a Building Control application.
Taking a fused spur from an existing circuit outside a special location is not a new circuit, so it is not notifiable on its own. That does not make it unregulated. It still has to comply with BS 7671, it still needs the circuit protective arrangements checked, and it still wants testing and a written record. The distinction matters for paperwork, not for whether the work should be done properly.
Special locations, where the rules tighten
A rooflight over a bath, a shower or a wet room sits in what the wiring regulations call a special location, and the zones around the bath or shower carry their own requirements on what may be installed and how it is protected.
In practice a control unit is never sited in a bathroom, the supply is taken from outside the room, and the equipment at the rooflight is extra-low voltage and specified for humid conditions. Fixings want to be stainless, because a warm damp atmosphere finds plated steel quickly. This is one of the places where the sequencing between trades is worth agreeing in advance rather than discovered on the day.
The paperwork you should end up holding
Two separate documents come out of a motorised rooflight job, and they cover different things.
From the electrical work, either an Electrical Installation Certificate where a new circuit was run, or a Minor Electrical Installation Works Certificate where an existing circuit was extended. Where the circuit was notifiable, a Building Regulations compliance certificate follows from the scheme provider. From the rooflight itself, the Building Control notification covering the opening, which Sunspire handles as part of the job.
Who does what, and in what order
The sequence on a typical job is settled and it prevents most of the friction between trades.
- Design stage. The position of the unit and the route for the cable are agreed, along with where the control unit will live.
- First fix. The electrician runs the mains to the transformer position and pulls the low voltage cable through to the rooflight opening while the ceiling is open.
- Installation. Sunspire forms the opening, builds or prepares the kerb, sets and weathers the unit, and makes off the low voltage connection at the head.
- Commissioning. The controls are paired, the limits set, and the unit run through several full cycles before anyone leaves.
- Certification. The electrician tests, energises and issues the certificate.
Solar units, and the case with no electrician in it
A solar powered opener carries a small photovoltaic panel on the outside of the frame and a rechargeable cell inside it. There is no mains connection, no transformer and no cable, so Part P does not come into it at all.
That is the whole appeal on an existing roof with a finished ceiling. It is also why solar comes up so often on the older Essex stock, where a Victorian terrace in Chelmsford or a weatherboarded cottage in the Blackwater villages has no convenient void to run anything through. What a solar unit actually delivers in daily use is covered on whether solar powered rooflights are any good.
Retrofitting into a finished room
Where the rooflight is already in and a motor is being added, the electrical question changes shape. The unit is in a ceiling that is closed, so the discussion is about the least disruptive route for a supply rather than the most convenient one.
Sometimes there is a lighting circuit in the same ceiling void that can be spurred sensibly. Sometimes the room above has a liftable floor. Sometimes the honest answer is that no concealed route exists and the choice is between surface trunking and a solar unit. An electrician looking at the actual void, rather than at a drawing, is what settles it. The conversion routes are set out on converting a manual rooflight to electric.
What to ask before the work is booked
Three questions remove nearly all the uncertainty. First, is the supply a new circuit or a spur from an existing one, because that decides whether the work is notifiable and how long the electrician is on site. Second, where is the transformer or control unit going to sit, because it needs to be accessible for the life of the installation rather than buried above a plastered ceiling.
Third, who is present on commissioning day. Pairing handsets, setting limits and testing a rain sensor go quickly when the person who terminated the supply and the person who set the unit are both there. Splitting that across two visits a fortnight apart is how a rooflight ends up sitting unpowered above a finished room. Sunspire settles the sequence at survey, and how the company works is set out on the about page.
Related questions
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