fluorescent lighting installation

[Amp David]

Had a look at a job earlier which is to replace 9 6ft twin fluorescent fittings in a small warehouse.

At the moment there is nearly 20 single 5 ft fittings, all fed from 1 32 amp MCB and on 3 switches. All cabling is in 1.5mm t+e believe it or not run on some cable ladder that runs the full length of the building.

My questions would be, Is it best or good practice to maybe split the switching of the 9 fittings into 3 lots of 3? As there is cable ladder installed, rather than installing conduit, then pulling in singles, would flex be an acceptable wiring method, cable tied to the ladder, then glanded into the light fittings?

If using HF fittings, will I still be required to use the 1.8 multiplier to do the calc for the circuit.

Thanks in advance

 

[nickblake]

not ideal really at all

fluorescents and sockets all on the 30mA

ther'd prob be some additional leakge if you use HF

you'd need the twin spots just for the nuisance trips alone- never mind blackout and local circuits tripping

One of my customers has a big industrial steel frabrication work shop one of four on site this work shop is full of welders HF flourescents ,drills , fork lift chargers ,and a massive sheet steel bending machine ,and a 30ma Main switch RCD which works perfectly it has tripped and does trip ,when there is a fault which with the nature of the work they carry out isnt suprising with hot wels burning cables and sharp metal edges that cables gets trapped on , tools are PAT testes every 3 months and at the same time the RCD's are tested and a visual carried out on sockets etc so may not nesseserily trip inconvieniently

 

[davelerave]

One of my customers has a big industrial steel frabrication work shop one of four on site this work shop is full of welders HF flourescents ,drills , fork lift chargers ,and a massive sheet steel bending machine ,and a 30ma Main switch RCD which works perfectly it has tripped and does trip ,when there is a fault which with the nature of the work they carry out isnt suprising with hot wels burning cables and sharp metal edges that cables gets trapped on , tools are PAT testes every 3 months and at the same time the RCD's are tested and a visual carried out on sockets etc so may not nesseserily trip inconvieniently

scary -100amp 4-pole ya

and more 30ma's downstream