Low voltage lighting has traditionally been a great choice when it comes to domestic lighting due to the fact that it can be installed in many locations that may otherwise be too unsafe to feature any form of lighting.
In this DIY project we take a look at low voltage lighting and how and where it can be used.
What is Low Voltage Lighting?
Low voltage lighting features a transformer that is used to step down UK mains 230V/240V power to a much lower and safer 12V, or sometimes 24V. In the US, mains line level electric is stepped down from 120V, again to a safer 12 or 24V.
As the overall voltage is reduced massively it then becomes much safer to use in situations that it would otherwise be much to risky to such as around water.
In terms of where it can be used, quite often it’s used in underwater situations such as in swimming pools and also in Zone 0 areas inside bath tubs and shower trays or where they will be in direct contact with water.
However, obviously the unit must also be fully sealed to prevent the 2 actually coming into contact with each other. In the very unlikely event that they do, the fact that the voltage is reduced so significantly means that any risk of injury is kept to a minimum.
Low voltage lighting is also used to great effect outdoors as again, as it’s exposed to the elements, if the sealed unit fails, any risk of injury is low.
Regulations for Low Voltage Lighting
As with any and all electrical work there are very strict rules that have to be followed when working around or on electrical circuits such as low voltage lighting circuits.
At present, the regulations governing work on any form of electrics and wiring is the British Standard BS 7671, now on its 18th edition. This came into effect on the 1st of January 2019 and covers all electrical work up to 1000V AC (1500 DC) and also LV (low voltage) and ELV (extra low voltage) systems such as lighting.
In terms of actually installing low voltage lighting systems, this should only ever be done by a qualified Part P electrician as, once installed, everything needs to be tested correctly and a minor works certificate issued and this can only be done by a Part P electrician.
When it comes to where it can be installed, as we have mentioned, in most cases it’s used where it’s likely to come into close contact with water or high levels of moisture such as in Zone 0 in the bathroom or outdoors.
Again, as both of these are special locations (see our project on bathroom zones here) no one other than a Part P registered electrician is allowed to work on them.
For further safety advice when working around electrics see our electrical safety project here.
It’s also possible that you will have several different colours of electrical cables in your home, both old and new colours. To understand more about this see our new wiring and cable colours project here.
How Can Low Voltage Lighting be Used?
Low voltage lighting can be used in a variety of ways. It is used as a safe option in highly dangerous areas such as kitchens, bathrooms and outside, essentially anywhere where it may come into contact with water or moisture.
Although any wiring and lighting unit should be totally sealed and IP rated (see our bathroom lighting project for information on IP ratings) according to the area it’s to be installed in, if there is a fault then the fact that it’s low voltage minimises any serious injury.
Low voltage lighting is also used to great effect when trying to create an ambience such as in a dinning room or living room, where lower level lighting is used to set a relaxing atmosphere.
Extra Low Voltage Lighting
The superb quality "specific" lighting you see in so many shops, art galleries, museums etc. is called Extra Low Voltage Lighting (ELV) but is commonly (and mistakenly) referred to as just low voltage lighting.
For the home owner this has opened up huge opportunities and existing lighting can be replaced, or just enhanced by the use of extra low voltage lighting.
Traditionally, extra low voltage lighting consisted of small tungsten halogen bulbs producing two or three times the light of conventional bulbs of equal wattage, but today these have been mostly replaced by LED bulbs.
As with low voltage lighting, they are powered by a 12 volt electrical supply rather than the 230 volts needed to power conventional lighting and are therefore fed through a (concealed) transformer.
As the transformer reduces electric usage, energy consumption compared to 230V/240V systems may be reduced by up to 60% although this really only becomes apparent when several conventional lights are replaced. Additionally, when coupled with LED bulbs this can save even more and also the lifespan of a bulb is increased more than 10-fold.
When halogen bulbs are fitted, they use special multi-faceted mirrored reflectors with sealed fronts so they can be used safely in bathrooms, kitchens and outdoors.
They use dichroic reflectors which means that the majority of the heat generated by the bulb is reflected backwards and not into the room. The light, as a result, stays relatively cool.
However when using LED bulbs, as they produce hardly any heat you don’t get any of the issues stated above, so on the whole this is now the way to go.
Low Voltage Lighting Categories
Lighting in the home falls into three categories – general, task and specific.
- General lighting: Provides overall space brightness with no concentration on any part of a room. Essentially it lights the whole room
- Task lighting: As you would imagine, provides light for tasks such as reading, sewing etc. where general lighting may be inadequate. It essentially directs the light over a smaller area
- Specific lighting: As the name suggests, is intended to highlight specific features without giving out to much light elsewhere, more like a spot light. A good example would be a low voltage light used to illuminate a picture on a wall
Planning Low Voltage Lighting Installation
When thinking about lighting for any particular room it makes sense to think about the function of that room and what will be done in there.
Most rooms will require a level of general lighting which, by the use of dimmer switches, can be transformed into various moods.
If you are using low voltage lighting for a complete room, the general rule of thumb is 18W halogen beam light per square metre or 6W LED (bulbs should be around the 400 – 500 lumen mark) or 50W halogen light per 1.5 square metres (or 10W LED). This rule starts half a metre in from the edge of the room.
Generally low voltage lighting transformers (if needed) are placed in the floor or ceiling void and it is very important to ensure they are in a well ventilated space. Do not cover them with insulation, remember, the heat comes out backwards. Never position transformers near central heating pipes.
In most cases you should also use a down light protector or hood to cover over the top of the light, protecting it from any insulation or the similar, however you should consult with a qualified electrician to ensure this is the right path to take as in some cases, it blocks the ventilation causing overheating!
Low Voltage Lighting in Kitchens, Bathrooms and Outdoors
As we have stated above, bathrooms have strict regulations as to the type of light fitting that should be used, and where.
Under the regulations, a bathroom is sectioned into three separate zones, zone 0, zone 1 and zone 2. Each zone of the bathroom is related to the position of the water source, i.e. bath, shower, basin etc.
Bathroom lighting is also given an IP rating. This IP rating is followed by a number and the higher both numbers are the better protection a light fitting has against dust and the ingress of water.
For example a standard ceiling light fitted in zone 2 should be at least rated as IP44, however a light fitting fitted inside a bath tub or shower tray (Zone 0) should be at least IP67 rated.
During installation, you electrician should be well aware of what type of product can be installed and where.
Kitchens also are subject to special regulations as, like bathrooms, they feature lots of water and moisture from the sink, cooking steam etc. so any lighting used here is subject to the same requirements. As with bathrooms, any work carried out in the kitchen should only be done by a Part P registered electrician.
For further information about installing kitchen lighting please look at our project on kitchen lighting.
Today, low voltage lighting is a little “old hat” as there are many stipulations that need to be followed, such as where the transformers are installed, making sure they have plenty of ventilation, using the right wattage of bulb etc.
Now, the real go-to solution is to use LED bulbs as they are much cheaper to buy and run, last much longer, are generally easier to install etc. so if you are looking at changing the lighting in a room or indeed your whole home, then this is probably the way to go. Find out more about LED lighting in our LED lighting project here.