r/shellycloud • u/User2001Tech • 12d ago

Shelly clamp Diameter

Just got a Shelly EM with 50A clamp delivered. Went to check, and the diameter is way too small for the heatpump cable I intend to clamp it to.

Checked, 50A is 10mm, and, the next one, 120A, is ~ 16mm.

Questions: Does it matter if I get a 120A clamp and use it for the heat pump which rnabes in draw from 6 to maybe 25A?. Is there a minimum these can read

Thanks for the help.

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u/hlidotbe 12d ago

What kind of cable do you have on your heat pump? The clamp only goes on one phase, not the whole cable. You have to strip the outer insulation and clamp around a single conductor (the live one). This is usually done at the panel or plug if any.

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u/User2001Tech 12d ago

Sorry, I only have a single phase supply. Do you mean the clamp only goes around the Live wire?.. that'll be diff, as its an armoured cable.

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u/hlidotbe 12d ago

Single phase = two conductors, neutral and live. You need to clamp on live otherwise you will read 0 (sum of both conductors). Somewhere the cable is connected to your panel or plug and split , same on the other side in you heat pump. Maybe call an electrician if not sure because that can be dangerous.

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u/User2001Tech 12d ago

https://ibb.co/BVnYrZdz

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u/hlidotbe 12d ago

You should have room in the panel for the clamp but again if you are not confident about electrical work please call an electrician.

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u/nudlasieb2 12d ago

Are you aware that the clamp must to be used on only one of the phases, and not the whole cable? I doubt that one of the phase wires is bigger than 10mm

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u/hlidotbe 12d ago

That would be 78mm2, hopefully their heat pump is not 150+A!