CECI Italy - Large wirewound enameled resistors and Wattage calculation

[Kiriakos GR]

CECI brand in Italy this might not be active any more, but it is a good example of European engineering.

CECI = societa elettrotechnica Chimica Italiana
And or ENG = Italian Chemical Electrotechnical Company

My adventure began when I started web search regarding a large wire wound enameled resistor, that I did salvaged many years ago.
Part Code: SECI RSS 25  15K J 

I have a DIY project ahead, and I wanted to find the Wattage of this resistor.
And I discovered instead, that CECI this using per product series, the length of its resistor this be divided by electrical application load, so the actual wattage this to be calculated.

Model RSS-25 15K
Resistance length 64mm
Resistance diameter 14mm
Tube inner  diameter 6.50 mm
According to electrical characteristics this is 25W as nominal.
But wait, this is a resistor with max operating voltage of 700V

My application this is at 230V AC:
Ohms law, 15K Ohm, 230 V = 15.3 mA , 3.52 Watt 
Resistance length 64mm this be divided by 3.52 Watt = 18.18 Watt, and this is the new nominal wattage according to operating voltage and load. 

Below are photographs of CECI RSS series samples.