How Do I Read An Old Spinning Disc / Mechanical Meter?

If you have an old, mechanical meter, and you want to track your electricity consumption, you'll have to learn how to read it. It is easy to read a mechanical, or spinning disc meter, but the method is not obvious. So I'll walk you through it now - and too help your understanding - I'll explain why the method is how it is. It is all to do with the old fashioned mechanism.

Have a look at your meter. The dials that tell you how many kWh you have consumed will look like this:

• This meter reads 16,863 kWh. Don’t worry, it’s not as complicated as it looks.
• You read the dials left to right.

Interestingly, because the meter dials are all driven by gears, dials 1, 3 and 5 move anti-clockwise and dials 2 and 4 move clockwise as you use electricity.

To read the meter, the most important thing to remember is always to take the lower of the two numbers when the pointer is between two numbers.

Dial 1

Look at the photo. Let’s start with Dial 1 (labelled 10,000 in the photo). The pointer is between the 1 and 2, but it hasn’t passed 2, so the reading is 1.

Dial 2

Dial 2 is trickier. The pointer is sitting over number 7. It’s hard to see if it is before or after 7.

So how do we know it it is 6 or 7?

When this happens, look at the next (third) dial and see where that pointer is. Dial 3 moves anti-clockwise as it increases.

• If dial 3 is anti-clockwise of zero, then it has 'gone past 10' and dial 2 is the larger of the 2 options.
• If dial 3 is clockwise of zero, then it has not 'gone past 10' yet and dial 2 is the smaller of the 2 options.

Looking at the photo, dial 3 is clockwise of 0, the pointer is coming up to 9, showing it hasn’t passed 0 yet.

So Dial 2 is still on 6 (even though it looks like it’s on 7).

Dial 3

Dial 3 isn’t quite at number 9, so that dial reads 8.

Dial 4 is between 6 and 7, so that reading is 6.

Dial 5, the last dial hasn’t yet fully moved to 4, so that reading is 3.

Put them all together and we have 16,863 kWh.