Level  Code   Description   Rulings   Reference to isic rev. 4   This item includes   This item also includes   This item excludes 
1 D   ELECTRICITY, GAS, STEAM AND AIR CONDITIONING SUPPLY     D   This section includes the activity of providing electric power, natural gas, steam, hot water and the like through a permanent infrastructure (network) of lines, mains and pipes. The dimension of the network is not decisive; also included are the distribution of electricity, gas, steam, hot water and the like in industrial parks or residential buildings.

This section therefore includes the operation of electric and gas utilities, which generate, control and distribute electric power or gas.   		Also included is the provision of steam and air-conditioning supply.   This section excludes the operation of water and sewerage utilities, see 36, 37. This section also excludes the (typically long-distance) transport of gas through pipelines.  
2 35   Electricity, gas, steam and air conditioning supply     35        
3 35.1   Electric power generation, transmission and distribution     351   This group includes the generation of bulk electric power, transmission from generating facilities to distribution centres and distribution to end users.      
4 35.11   Production of electricity     3510   This class includes:
- operation of generation facilities that produce electric energy; including thermal, nuclear, hydroelectric, gas turbine, diesel and renewable   		  This class excludes:
- production of electricity through incineration of waste, see 38.21  
4 35.12   Transmission of electricity     3510   This class includes:
- operation of transmission systems that convey the electricity from the generation facility to the distribution system   		   
4 35.13   Distribution of electricity     3510   This class includes:
- operation of distribution systems (i.e., consisting of lines, poles, meters, and wiring) that convey electric power received from the generation facility or the transmission system to the final consumer   		   
4 35.14   Trade of electricity     3510   This class includes:
- sale of electricity to the user
- activities of electric power brokers or agents that arrange the sale of electricity via power distribution systems operated by others
- operation of electricity and transmission capacity exchanges for electric power   		   
3 35.2   Manufacture of gas; distribution of gaseous fuels through mains     352   This group includes the manufacture of gas and the distribution of natural or synthetic gas to the consumer through a system of mains. Gas marketers or brokers, which arrange the sale of natural gas over distribution systems operated by others, are included.

The separate operation of gas pipelines, typically done over long distances, connecting producers with distributors of gas, or between urban centres, is excluded from this group and classified with other pipeline transport activities.   		   
4 35.21   Manufacture of gas     3520   This class includes:
- production of gas for the purpose of gas supply by carbonation of coal, from by-products of agriculture or from waste
- manufacture of gaseous fuels with a specified calorific value, by purification, blending and other processes from gases of various types including natural gas   		  This class excludes:
- production of crude natural gas, see 06.20
- operation of coke ovens, see 19.10
- manufacture of refined petroleum products, see 19.20
- manufacture of industrial gases, see 20.11  
4 35.22   Distribution of gaseous fuels through mains     3520   This class includes:
- distribution and supply of gaseous fuels of all kinds through a system of mains   		  This class excludes:
- (long-distance) transportation of gases by pipelines, see 49.50  
4 35.23   Trade of gas through mains     3520   This class includes:
- sale of gas to the user through mains
- activities of gas brokers or agents that arrange the sale of gas over gas distribution systems operated by others
- commodity and transport capacity exchanges for gaseous fuels   		  This class excludes:
- wholesale of gaseous fuels, see 46.71
- retail sale of bottled gas, see 47.78
- direct selling of fuel, see 47.99  
3 35.3   Steam and air conditioning supply     353        
4 35.30   Steam and air conditioning supply     3530   This class includes:
- production, collection and distribution of steam and hot water for heating, power and other purposes
- production and distribution of cooled air
- production and distribution of chilled water for cooling purposes
- production of ice, for food and non-food (e.g. cooling) purposes