Measuring what is actually consumed PDF Print E-mail


The plate rating of the device quite often indicates the maximum amount drawn. Whilst you’d think that the maximum wattage was just that, no matter the configuration or deployment, the wattage actually drawn might be even greater. This may be due to a number of factors

a.    the device may be connected to a number of other devices or peripherals whilst it is being used eg a monitor, an external storage device (USB data stick), or a communications card.

b.    Many device technical specifications detail the power output, not the power input.  A device in operation, for example a photo-copier or PC server, will draw a higher rating when operating intensively.

c.    For devices with mechanical moving parts, a spot reading of the electricity being drawn by the device will not confirm the amount used over a longer period; you should consider measuring a device for prolonged periods.

d.    Some devices will draw a small amount of electricity even when switched off;  but still connected to a live mains electricity supply.

e.    Be warned that some external power supply adaptors if left plugged in continue to draw power even when the device has been switched off.