Hi,

In what circumstances do you use a circular junction box over strip connectors in a choc box and vice versa? From what i can tell they seem to serve the same purpose so any guidance would be useful as i need to spur off an existing lighting circuit to fit an outside light and want to be sure I'm using the correct equipment for the job.

Thanks

The strip connector block is designed to go inside something. Be it a light fitting or an enclosure, the latter may be a junction box. The main thing is the IP rating. On the top no more than 1mm and on sides think from memory 12.5mm (finger proof). Also it must need a tool to access so tape will not do.

However self amalgamating tape may pass as one needs a knife to cut it off. But then there is the question of maintenance and you need access to check tightness of screws so self amalgamating tape would not allow that.

There are maintenance free types that use spring clips rather than screws. The problem is vibration i.e. people walking on the floor, can cause screws to work loose. Hence why one should not use a junction box with screws below a floor board. Although many do.

Using the old round JB in the loft where all cables are cleated so no need for cable clamps and very visible for maintenance was very common. But today with loft insulation which can so easy hide the box and as a result it gets stepped on means their days are numbered. The polyurethane type which may deform when stepped on but does not break into bits when stepped on has in the main replaced the old round JB. Often the polyurethane type have connector strips inside them.