Gives requirements for 300 A bolted flameproof cable couplers and adaptors of semi-screened 3-phase or 3-phase plus centre pilot tube with voltage ratings: 3.8/6.6kV. Designed to enable two cables to be coupled together or to enable a cable to be coupled to apparatus by use of adaptors, in both cases the electrical connections being made be separate connecting pins. Provision is also made for insulated end covers. The use of other forms of intermediate box, with coupling arrangements as are not precluded provided that all other relevant requirements are met.