Occasionally referred to as 'Skeleton Boards', these are spine backplate assemblies designed to fit within a Mantel or Clifton type enclosure which is essentially a type of metal utility cupboard which may also contain an electric meter.

Many local authorities historically favoured skeleton consumer units as the main framework for consumer protection within homes.

Electrical contractors did not like this type of consumer unit due to it being very awkward to work with, it can result in some eccentric arrangements and hazards arising in fault conditions such as the RCD tripping due to a simple bulb blowing downstairs and then plunging the entire house into darkness. Of course, electric installers working on older social housing still come across these and experience some difficulties in bringing the property up to current electrical safety standards. 

Although skeleton consumer units are very outdated, there is still a market for them, mainly for replacement purposes rather than an upgrade. This is because the applications and/or locations can make it tricky to substitute them with a modern fuse board- either for reasons of space or the ability/inability to provide sufficient circuits.

Fortunately, the modern equivalents take much of the fuss away and provide a faster, cleaner and easier installation than would have previously been the case.