Friday, September 3, 2010

Create a Standard Low Voltage Circuit in the Home.

I propose that building codes be changed to enable a low voltage circuit to be standard in buildings, particularly the domestic home. I refer to this as a Low Voltage Main (LVM)


Some facts:

1: Most electrical items in the home do not require current mains AC voltage (EU 220v, UK 240v, US 110v) to operate and so a transformer is used to reduce the voltage. Transformers consume power and resources for no gain.

2: Most electronics use DC current.

3: PV Solar Panels produce DC voltages in the range 12 - 48 volts

4. DIY work on mains circuits, particularly in kitchens and bathrooms, is subject to strong regulation for good safety reasons.

5. Voltage standards in the home vary around the globe, whereas most internal voltages in TV, Computer, Mobile devices, Automotive devices are standard around the world.

6. The power required for devices in the home is reducing with new designs and technology. Where it has levelled off (eg Graphic cards, Plasma TV's) the management of the power consumed is getting smarter.

Details of proposal:

A mains voltage supply (usually 220/240v AC) would be retained for high load equipment such as washing machines, freezers, ranges/oven etc.

To allow retrofitting and staged remodelling, the existing lighting circuits could be separated at the consumer unit. CFL and halogen lamps would be replaced with LED or electroluminescent units.

As lighting circuits are usually available in the loft, they are in the best place for the direct connection of PV panels without the need for high power inverter units.

12-48 volt DC storage would be included directly connected to the LVM, it would allow charging by solar PV or by a wind, water, biofuel powered generator. Alternatively power could be stored during low cost grid power times or when other sources are not available for use via the LVM.

Lamp fixtures are usually available in the ceiling and offer a viewing area that would make the ceiling rose an ideal place to mount sensors such as smoke, heat, humidity, temperature, movement etc. for safety, energy management and home automation purposes.

The standard should allow the use of standard data connections and wiring such as RJ11, RJ45, CAT5, TCP/IP and simple low cost adapters such as RJ45 to microUSB, USB, Car Cigar Socket, etc.

These connectors are available worldwide and produced in very large quantities so cost and availability is improved. Moving equipment between countries would not require any conversion.

Over-voltage protection should be included and smart voltage selection could be provided by data being sent from the requesting device identity codes. This would be possible by using Power-over-Ethernet standards at the low voltage source. Companies such as Cisco already produce suitable devices as Network routers and Uninterruptable Power Supplies, that could be easily adapted to such use.


  1. Interesting 48V would be the one to go for as there is the existing telco and DC gear that runns on 48v.

  2. I have posted this idea over at and received the following helpful comment, so I am cross posting it here.

    harland.john said:

    Low-voltage current doesn't travel far without big losses. The idea is attractive, however, from the angle of facilitating the plugging-in of many of the low-voltage applications of the home into a single, more-efficient, low-voltage source. We, for instance, have a cluster of computers, screens, modems, networked disc drives and other stuff in one corner of the room, for instance, and running all from a single feed would seem to offer a big lift in efficiency.