Current sensors on ceramic fuses

  Hi Everyone,

  I've just come across this project, it looks really interesting. I'm keen to use a emonTx to monitor my power usage. However I'm currently renting an apartment - the meter box is outside and a long way from my actual apartment, so I don't really want to leave any gear in there (also not sure if the wireless would reach). Being a renter I can't just get a sparky in to make any changes to wiring.

  However there is a fuse box near my front door which has the old-style ceramic fuse holders. I'm wondering firstly if in theory putting a current sensor around these fuse wires would work, and secondly if anyone has done it before. I'm not sure if there's enough space to somehow safely get a sensor into the fuse holder?

  Hmm, not having much luck attaching a picture of the fusebox, maybe just putting a link to my google drive will work ...


    - Rob


Robert Wall's picture

Re: Current sensors on ceramic fuses

You can put the CT on anywhere on the cable, it doesn't have to be at the meter nor at the fusebox, as long as the cable carries the current you want to measure! However, I wouldn't try to fit a CT around the fuse holder itself. These are a little more complicated than they appear and for correct operation of the fuse, depend on the rate of heat transfer from the wire to the surroundings. [E.g. if you thermally insulate the fuse, it will rupture at a lower current than you expect.]

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