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]

the 1.8 multiplier is to conpensate for the ballast so if using HF ballasts their is no need for it , is the supple single or three phase , if its three phase then i would split between phases , reason for this is the fact that there is a 50hz flicker on flourescents which in some circumstances can make moving machinary look stationary IE :lathes drills saws etc but buy using different phases this cancels out the flicker and i would do as you by splitting the lights into banks ,and as a good measure put some twin beam emergency lights in to with a test key at the switch bank ,cant see any reason why you cant use flex as long as its protected or not at risk of damage and current carrying capacity are within the requirements

Nick

 

[Amp David]

Cheers Nick.

See your point regarding HF fittings, so I can use the stated wattage to calc from?

Its single phase, but thought about splitting just for switching purposes, so they don't all have to be on together.

 

[nickblake]

makes sense with all the energy saving these days

 

[davelerave]

good idea to split them anyhow-for maintenance and simple avoidance of blackout,

as already said i don't think the 1.8 multiplier and 50hz flicker apply to hf ballasts

 

[Hawk81]

one 32amp mcb feeding 1.5mm? interesting. I would be spliting the lights and putting in an appropriate mcb.

 

[davelerave]

i would keep in mind the ambient temperature and covers if using 6ft's


they could be a pain to start if it's cold

 

[Amp David]

one 32amp mcb feeding 1.5mm? interesting. I would be spliting the lights and putting in an appropriate mcb.

Yeah, I found that bit interesting. Looks like the last guy just stuck in what he had. If all the fittings were actually working then i think he'd of had melted cables before now

 

[Amp David]

i would keep in mind the ambient temperature and covers if using 6ft's


they could be a pain to start if it's cold

Do you mean covers for the tubes?

Didn't think the starting was affected with HF ones if it was cold

 

[nickblake]

have you seen the anti shatter covers for tubes that would be so good the amount ive broken in the van , i did notice the 1.5 on 32 amp mcb didnt need to mention it because im sure david being the proffesional he is will sort that out , i cant remember wether you said you were splitting the circuits to multiple MCB's or just switches would be a good idea on multi ple circuits then if you loose a circuit you dont loose everything ,

david , i did have a bizzar situation with HF and tubes and dave elec has said , i was in a church upgrading the lights it was cold in the - when we had the very cold spell before xmas we replaced all the 1060's ballasts for modern HF ballasts and when we powered them up they were pink and had a rolling sphear it was very wiard never seen it before but after about 10 mins it went to full brightness and has not given any problems since

 

[Amp David]

You're right Nick about splitting over multiple MCBs, only problem is that customer won't want to fork out the extra on a bigger board. At present its a single phase sub board, 8 way and its full. Best part is that all circuits are protected by a 30ma RCD

My plan is to stick to what the customer asks for, provide him with quotes for his ideas and then mine and see what he does.

He's one of these guys who will only ever want the basic job done. For example his forklift charger keeps taking out the RCD on the same board. Advised on putting it on its own small CU, but wasn't interested. So instead he comes in every morning just hoping it didn't trip 10 minutes after locking up the night before

 

[mayfair]

Just a note for those interestead in whats going on in the rest of EU By law we would have to split into 3 zones Probably 3 10A mcb's emergency lighting circuits on each of three zones then seperate switches on ech zone .....No more using mcb's as light switches . Just posting this as it may be of interest to some.

 

[Amp David]

Would never even dream of use the MCB as a light switch anyhow.

Emergency lighting hasn't been mentioned, so will hopefully do this job, then when the H&S chaps pops back in and says wheres your emergency lighting, I might get the work!

 

[nickblake]

think a few twin beams would work a treat on that job

 

[davelerave]

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

 

[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