what is the word i am looking for? clock, meter???
 

I want to install a device that measures the time an electric appliance is running.

for example, how many hours is my Oil Burner running a day?

so, what do you call that device? where to get one?

Meter.

Check Grainger, McMaster-Carr or MSI.

Also check the Fluke website. You're gonna pay $$$ for something like this. Why not rig up an hour meter like they have on boat motors?

http://www.grainger.com/Grainger/items/6X139

I think they're regularly called an "hour meter".

kilowatt-hour meters and around $400 from Grainger

or
http://enmco.thomasnet.com/category/enm-counting-instruments-hour-meters? $166

Hour meter.
Cheap.

Ding! thanks everyone.

Harbor Freight sells a Killawatt that measures throughput and duration for about $30, IIRC. I have one and it's a nice product. It shows voltage, current, consumption.

ETA: Here the product at Amazon.

http://www.amazon.com/P3-International-Kill-Electricity-Monitor/dp/B00009MDBU/sr=8-3/qid=1161332551?ie=UTF8&s=electronics

Related article: http://www.mymoneyblog.com/archives/2006/10/frugal-gadget-save-money-with-a-kill-a-watt-energy-meter.html

Couldn't find the Killawatt I have at HF, but here's a different one:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=65731

I have always heard them called Elapsed Time Indicators.

That what engineers call them. The rest of us booger-eaters call 'em "hour meters". :D