Cavity wall insulation. Cavity wall insulation is used to reduce heat loss through a cavity wall by filling the air space with material that inhibits heat transfer. This immobilises the air within the cavity (air is still the actual insulator), preventing convection, and can substantially reduce space heating costs.
âStandardâ wiring puts both grounds at one end of the socket. âCKâ wiring puts grounds on one side of the socket. This makes no difference to an incandescent bulb, because the filament is not sensitive to polarity. However, installing âStandardâ wired LEDs in âCKâ sockets may cause them to catch fire or blow fuses.
For socket wrenches to fit metric bolts, go here. The tables below show the commonly-available sizes of socket wrench and the fasteners they fit. The 8-pt sockets fit only square heads. A 12-pt socket fits both hexagonal and square heads. Twelve-point sockets also fit 12-pt heads (which are found only in aerospace bolts).