DIN 44874-3
DIN 44874-3 Electrical metal sheated tubular heating elements; 6.5 mm and 8.5 mm diameter, determination of ageing and overload characteristics
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 06/01/1980
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 06/01/1980