Measure Electricity Usage in a School


We are a group of 13 primary schools in the UK, we would like to measure the electricity usage in each of our schools in order to educate children (and staff!) on saving energy.

At home i would normally use a clipon sensor but of course in larger buildings the incoming supply if far thicker.

Is there a way for us measure electricity without getting a qualified electrician in?

EDIT: How reliable are the pulse sensors?

Yes. Our emonTx & emonPi use clip on current transformers to measure current, and an ordinary 13 A socket to measure the voltage. So if you only want to measure the total consumption of the school, you need only access to the main cables into or out of the meter to pop a c.t. on, you don’t need to break into any circuits or disturb any wiring. There are a few pictures on this forum showing a c.t. in position - but the law of natural perversity prevails and I can’t drop on one when I want one.

Are your schools large enough for a three-phase supply? I assume so from this:

You’re not tied to the “shop” c.t. With a bit of customisation, a wide range of c.t’s can be used - some only requiring a firmware change. They are listed on our “Using the emonTx in North America” page in the ‘Learn’ section.

We’ve had I think two instances of malfunction that I know about. One was due to the morning sun falling on the meter and blinding the sensor, I can’t remember the problem with the other. One caution: if you have - or are likely to get - a PV installation, the main tariff meter doesn’t emit pulses when exporting.

Hi Nathan,

I’ve just suggested the same to the head of the school I work in. I have an emonpi at home and think that the school would benefit enormously from having this system installed, especially the energy consumption when the school is closed.

Have you installed one yet?