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


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…


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


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.