Caution:
Electricity can be dangerous. Beware of any exposed wires. Work on any electrical apparatus or wiring should only be carried out by a competent person.
Cutting down standby power consumption is one of the most effective ways of saving electricity and money without having a significant effect on your lifestyle. Having been round the house and sorted out all the obvious things using power on standby there is a very high chance there are hidden items consuming electricity without you realising. The trick is finding them.
The simplest way to find these hidden consumers is by monitoring the electricity supply into the building. If you have a modern digital electricity meter it is not really suitable for spotting this problem due to a lack of sensitivity. The older type mechanical meters can be used by watching the spinning disc - if it is going round electricity is being used (higher speed) = higher load)- however this is only an indication, providing very little information as to how much power is being used. The best method is to use a Clamp Meter which will measure the current through the cables (although not very accurately at low currents). The meter is fitted around either the live or neutral cable into the fuse box or main earth leakage trip - the photo shows how this is done.
Switch off all the individual circuit breakers (including the main on/off switch) or remove all the fuses on the fuse box and the reading should be close to zero. Unfortunately it is often not possible to tell which wire is live and which is neutral so check the current in each. The neutral cable should have a small reading and the live cable should be zero. The reason for the neutral current being higher is due to leakage to earth. High figures on the neutral or a non zero figure on the live cable need to be investigated by a competent person as this could indicate a wiring fault. See the electricity measurement tips for more information on clamp meters. Refit the clamp meter to the lowest current cable (which should be live).
Now make sure absolutely everything in the house you can find is switched off - unfortunately this could well mean some time switches will need resetting afterwards. Switch on the circuit breakers or replace the fuses one by one, turning on and off the the main switch each time, and check the current. Any significant reading indicates a hidden consumer or a wiring fault on that circuit.
A few of the items you could find are shown below:
- Unswitched shaver socket in the bathroom (typically these have an isolation transformer which draws current)
- Front door bell transformer (often well hidden and forgotten)
- Igniters for gas hobs and cookers
- Television aerial distribution amplifier
- Television mast head amplifier
- Electric water softener
- Burglar alarm
- Central heating time switch or controller
- Electric hot water heater time switch
- Outside lights with passive infra red detectors or light sensitive detectors
The difficult part often is finding these items to switch them off or unplug them and prove they are the culprit. Once the items have been identified a decision can be taken what to do with them. It is always worth having a good look around the loft. All of the items referred to above should be either plugged in or have a switch to isolate them.
As items are identified and switched off it is possible the current drawn will rise rather than fall - this is due to the effect of power factor at low currents - see the electricity measurement tips for a brief explanation of power factor. Remember at low currents the clamp meter is not that accurate and is more for indication of change.
