3 phase factory lighting

[bal]

how about using 10A 3 pole pole mcb's each feeding one contactor this gives 10 * 230V = 2300 W per phase
divide this by 1.8 correction factor gives 1278 watts per phas divide this by 250w (perlamp) = 5 fitting per phase 15 per contactor. This means only 4 contactors for 60 fittings.

split the fittings into banks and you will only lose a quarter of all the fittings if an mcb trips

Thats exactly what I was thinking but usings4 pole contactors. Excellent idea about the 3 pole MCB to cover but I was thinking 25amp.

Take a look at the diagram that I'm posting and let me know what you think. Should I have a 4 pole MCB for the 3 phase or 3 individual fuses??.



regards

 

[bal]

Lighting diagram attachedView attachment lighting.pdf

 

[nickblake]

Definatly type C with the inrush current of the son type fittings you could have a tripping problem ,if each of the fittings are 250 watts thats = 10 x 250 x 1.8 correction factor = 4500 so
divide that by 230 = 19.56 amps

may want to use 5 fittings per circuit

hope that helps

 

[nickblake]

looking at the diagram the main mcb may cause problems very close to the limits and if you do get a fault its probably going to trip the 25 amp MCB loosing all four circuits , best option i feel is mcb , contatcor, light and also any link wires between the main mcb and the sub mcb would have to be 6mm although only short runs , feel its adding extra cost and work

 

[bal]

looking at the diagram the main mcb may cause problems very close to the limits and if you do get a fault its probably going to trip the 25 amp MCB loosing all four circuits , best option i feel is mcb , contatcor, light and also any link wires between the main mcb and the sub mcb would have to be 6mm although only short runs , feel its adding extra cost and work

Nick,

I was looking at maybe a 50amp 3p + N to cover the 3 phase in feed so no phase overloads (see new diagram) - also isolates the whole control box from a single point, although if tripped it would turn all the lights off (we do have emergency lighting) - do you think I should instead use 50amp fuses instead so if tripped I would at least have some lighting on??. The B25's are covering the contactors which would be 25amp. Agreed on the 6mm wire between each phase of the input 3 phase and the B25 MCB. Cost is no problem - this layout gives us the ability to control via 24vDC, programmable relay, or simply to 24dc relays and switches located anywhere in the factory.

 

[nickblake]

Fuses sound a good idea to prevent loosing all the lights , what still concerns me is the amount of lights per mcb 10 thats alot of load as you can see from previouse message .on drawing its a B6 , i am correct is saying 250 watt each or am i mistaken and they are son / MH . I take it you mean a 50amp MCB dont get mixed up with isolator and MCB , MCB's dont like being used as switches , so you could always use a switch fuse say 63 amp switch fuse and derate the fuses accoring to your loadings then you can protect the circuit and isolate as well ,instead of using an MCB for isolation

 

[pmac10]

bal, cant see your diagram mate, but wouldnt bother fusing neutral as it provides a safe current return path for imbalanced loads. if the fault doesnt blow a fuse on the way in, its not likely to blow one on the way out having done work

 

[mogga]

on street lighting circuits we had problems when running anymore than 6 no400w son t fittings if one went faulty it would take out the mcb rather than the fuse in the fitting due to the additional fault time req for fuse against mcb


ie 400wx1.8 /230v = 3.14a per fitting 5 per curcuit =15.6a each fused @ 10A the mcb trips taking them all out as nick says

 

[bal]

Fuses sound a good idea to prevent loosing all the lights , what still concerns me is the amount of lights per mcb 10 thats alot of load as you can see from previouse message .on drawing its a B6 , i am correct is saying 250 watt each or am i mistaken and they are son / MH . I take it you mean a 50amp MCB dont get mixed up with isolator and MCB , MCB's dont like being used as switches , so you could always use a switch fuse say 63 amp switch fuse and derate the fuses accoring to your loadings then you can protect the circuit and isolate as well ,instead of using an MCB for isolation

Thanks for the pointers Nick - on further investigation the lights are mercury vapor 250w single phase.

I'm thinking of changing the MCB's from B to C rated and increasing the supply to the whole box (see reply to Mogga below- "you reckon I should up the whole supply?? ie 60amp feed, C30 MCB to 30A contactor to C10 MCB's to lights to cover any current surges".

Good idea about the switch fuses, I didnt know that MCB's dont like being used as isolators - can you recommend a manufacturer??

Thanks for all your input.

regards

 

[bal]

bal, cant see your diagram mate, but wouldnt bother fusing neutral as it provides a safe current return path for imbalanced loads. if the fault doesnt blow a fuse on the way in, its not likely to blow one on the way out having done work

As per Nickblakes suggestion - I'm going to install switch fuses, understand your suggestion about not having to fuse the neutral - thanks for the suggestion, I'll change my scheme.

regards