What is it: draws 4.5kw, turns itself on every ~7h, runs for exactly 5 minutes


Sense identified it as a the “Oven broiler (Kitchen)” and it looks a bit like it - except that when I turned off the breaker for the oven, overnight, that thing didn’t go away and kept turning itself on for exactly 5 minutes every 7 hours or so.
Of course I can continue experimenting, turning off my breakers one by one - but is there an easier way to figure out what device it could be?

It looks like some heating element. No real overshoot at the beginning so it isn’t a motor or anything with a giant inrush. The little peak might be the heating element that warms up and gets slightly higher resistance so lowering power slightly.

A fridge has defrost element to keep the doors from freezing shut, but that is few hundred watt.
The fact that it pulls it for 5 minutes means there is no fuse that is giving up.

If you are in the USA:
4500 watt /120 volt = 37.5 amps.
That is lot and not a common hookup.
so that would mean 240 volt setup which is roughly equivalent to 230 volt rest of the world.

4500 watt / 240 volt - 18.75 amps so you are looking at 30 amps double breakers or larger in your breaker panel.

What items do you have connected that have a possible 4500 watt heating element ?

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that is the wattage of my hot water heater element

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Normally a hot water heater is on longer than strictly 5 minutes every 7 hours isn’t it ?
If/when it needs to replenish water gone cold, I would assume it would use the thermostat to switch off again, not a timer.

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That’s a great lead! I do have a water heater tank that’s connected & working but not being used. I’ve been thinking of what heating element it could be based on your earlier message Danny, but I totally forgot about that water heater. Thank you klevorick! Will unplug it and let you know if it was the culprit…

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It was indeed that old water heater, sitting plugged in but unutilized, costing me $27/year :slight_smile:
Thank you!

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WooHoo! excellent to hear

If mine (60gal dual element electric) is not being used (I am away), the loss of heat is sorta constant and will trip the thermostat on a fairly consistent basis.