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HMRC internal manual

Capital Allowances Manual

Plant and Machinery Allowances (PMA): meaning of plant and machinery: electrical installations and other mains services

For expenditure incurred on or after 1 April 2008 (CT) or on or after 6 April 2008 (IT) see the guidance on integral features starting at CA22300.

For expenditure incurred before 1 April 2008 (CT) and 6 April 2008 (IT), the following applies.

Accept that an electrical system in a building is a single entity of plant if and only if all of the following conditions are satisfied:

  • it is specifically designed and built as a whole, that is it is a fully integrated entity;
  • it is designed and adapted to meet the particular requirements of the trade;
  • the end user items of the electrical installation function as apparatus in the trader’s business;
  • the electrical installation is essential for the functioning of the business.


If an electrical installation does not satisfy the above conditions adopt a piecemeal approach.

You should accept that the following items are plant:

  1. the main switchboard, transformer and associated switchgear provided that a substantial part of the electrical installation - both the equipment and the ancillary wiring - qualifies as plant;
  2. a standby generator and the emergency lighting and power circuits it services;
  3. lighting in sales areas if it is specifically designed to encourage the sale of goods on display;
  4. wiring, control panels and other equipment installed specifically to supply equipment that is plant or machinery.


Lighting which is within (c) qualifies even if there is no other lighting. You should treat the public areas in businesses like banks and building societies as sales areas.

Adopt the same approach to cold water, sewerage and gas systems as you do to electrical systems. Most cold water systems etc. should not be looked at as a single entity and you should adopt a piecemeal approach to them. The case of *Bridge House v Hinder 47TC182 *considered the question of sewers in relation to a restaurant and concluded in that case that they were not apparatus employed in the trade, but rather part of the setting enabling trade to be carried on.