Feature, Office

Can power over Ethernet transform how we control lights in the workplace?

The humble Cat 5 cable - now capable of carrying power to your lights as well as data

LED lighting is helping buildings around the world slash their electricity bills because the amount of energy needed to run LEDs is so much lower than that consumed by traditional forms of lighting.

But lower energy consumption isn’t just about saving money and being kind to the environment. It’s starting to demonstrate other benefits too.

The electrical load of LED sources is now so low that you don’t even need mains cables to power them – you can use standard network cables, so it’s easier and cheaper to connect and control your lights.

This technology is called ‘power over Ethernet’ (PoE) and, as the name suggests, it’s a way of providing power for electrical equipment through Ethernet cables – the same ones that already form the backbone of the IT network in your office.

Ethernet uses ‘cat 5’ (or more recently cat 5e or cat6) cables – the kind you plug into your router, with the plastic clip on the end that clicks into place.

Cat 5 cables are really designed to carry data, not power. But as long as the load is below a certain wattage (up to about 60W at the moment) they can power and communicate with devices at the same time. Which turns out to be really useful.

So what are the advantages for lighting? Well, everyone knows that wiring up a new lighting system can be an expensive headache, and to install a control system, you’ll need yet another network of wires up in the ceiling, along with the power cables.

If you want control but can’t face all that wiring, you’ve got three options: send the data wirelessly (using specially equipped drivers), send the data over your power cables (using power-line communication, offered by the likes of Lumenpulse and Echelon), or send the power over your data cables – in other words, PoE.

The great thing about using cat 5 cables for this kind of thing is that they’re cheap to buy and even cheaper to install – no need for an electrician, just click the cables into place and you’re away. Philips, one of the suppliers of power over Ethernet systems for lighting, reckons installation is up to 25 per cent cheaper than conventional wiring.

But that’s just the beginning – the real savings are in the longer term.

The next big advantage is the level of intelligence that an Ethernet-based control system can bring. Every light becomes a point on a network, with its own IP address. That makes it easy to control and monitor them (including remotely over the web), and if your light fittings incorporate presence sensors, temperature sensors, light sensors and so on, you can track that data too.

PoE brings lighting into the ‘internet of things’, allowing you to connect your lighting to other devices and systems in the building, such as heating, ventilation, IT services and security. The facilities manager has a single system that shows exactly how the building is being used.


Up and running

Philips already has a PoE lighting control system up and running at a new Amsterdam office building occupied by accountancy firm Deloitte.

UK-company Prolojik also has a power over Ethernet system, Light Matrix, that it sells with luminaire makers Future Designs and Phi Lighting. The system is installed in a meeting room at the offices of PricewaterhouseCoopers in central London, to power and control 20 direct/indirect luminaires.

Other companies working on PoE for lighting include Iowa-based Innovative Lighting and California’s Nuleds.

To use Prolojik’s power over Ethernet system, you need a black box called an Ethernet switch, which converts AC mains power to the DC that goes through the cat 5 cables (achieving 10 per cent efficiency savings over a standard setup where mains power goes all the way to the driver, Prolojik says). Once the switch is installed, the electrician’s work is done. It can power up to 3kW of lighting: it has ports for 48 cables, each of which can be used to power and control 60W of lighting – enough for maybe one or two luminaires each. Any luminaires rated up to 60W can be used with the system, although it does require Prolojik’s Dali drivers.

Mark Vincent, commercial director of Prolojik, says the ease of installation is a big draw for clients. ‘When we’ve been presenting this, I’ve been apologising to electricians and contractors, because we’re taking their business away,’ he says. But the real benefits are in fully addressable control of lights, and the long-term energy-efficiency benefits.

As with Prolojik’s system, the Philips system works with third-party luminaires, and talks to any existing control systems that may already be installed in a building. Philips’ PoE system is based on a network of small Ethernet switches, so it can be scaled from powering a handful of luminaires to 1,000 of them.

Jeff Cassis, senior VP of global lighting solutions at Philips Lighting, says: ‘You can extract whatever data you want, whenever you want. Not only can you monitor energy consumption per light source, you have this really granular ability to look at what’s happening on my floor or building, aggregate that and understand how people are using the spaces. If you have multiple sites or buildings, you can look at how different buildings are managed. You could see how to use certain areas better, cool areas down that aren’t being used and make extra savings due to occupancy.’


  • This special Lux conference for Facilities Managers is taking place on Thursday 19 May 2016 at the Cavendish Conference Centre in London. Entry is free to specifiers including facility managers, consulting engineers, estate managers, energy managers and others responsible for the management of lighting installations and their specification. 
  • View the full programme and register for your free place by clicking on the logo