Help with College task

[Mike Irving]

Hi guys, I'm a 3rd year electrician student and need some help.

I've been giving a task to do over the summer, it involves selecting a wiring system for a lighting circuit in a Army barracks switch room...The Fluorescent Luminaire

are 1800mm 2*70w ip65 and the cable is going to be in Galvanised conduit.

the building has 51 fluorescent tubes split into 4 room, which will be on 4 individual circuits

Sub station 16 tubes

Switch room 25 tubes

Work shop 12 and Maintenance room has 6

When working out the switch room for example the calculations i am using are (2*70*25)/230v gives me 16.52A so the breaker i would use is 20A is this right. 

Kind regards 

Mike

 

[Manator]

The question states that the circuits are to be split over 4 lighting circuits. Bear in mind that most lighting accessories are only rated at 16amp max.

You need to do a break down of all circuits and wire them accordingly. Remember switching.

 

[Murdoch]

Is it single phase or 3 phase?

 

[kerching]

Isnt the 1.7 / 1.8 only if the lamps are switch start?...having said that it does not say f they are HF or,SS anyway

 

[Mike Irving]

It doesn't say...the only info I have is the electricity supply is 11kV/400/230V.....I assume it would be single phase.....

 

[Mike Irving]

Isnt the 1.7 / 1.8 only if the lamps are switch start?...having said that it does not say f they are HF or,SS anyway

Hi it does not day on the plans if HF or as the only thing it says is 1800mm and 2*70w ip65

 

[bluetobits]

the building has 51 fluorescent tubes split into 4 room, which will be on 4 individual circuits

Sub station 16 tubes

Switch room 25 tubes

Work shop 12 and Maintenance room has 6

51?

 

[Mike Irving]

51?

51 is the total number of fluorescent lights.....

 

[Mike Irving]

Oops it should be 8 in the sub station 25 in the electrical switch room 12 in the workshop and 6 in the rest area...

 

[Rob_the_rich]

When working out the switch room for example the calculations i am using are (2*70*25)/230v gives me 16.52A so the breaker i would use is 20A is this right. 

I get 15.21A, so a 16A breaker would do. Probably a Type C. Use banks of switches, eg 1 switch for 5 luminaires. Metal Switches (army fingers). Possibly separate cpc single in conduit for high earth leakage current from all those ballasts?

 

[Mike Irving]

I get 15.21A, so a 16A breaker would do. Probably a Type C. Use banks of switches, eg 1 switch for 5 luminaires. Metal Switches (army fingers). Possibly separate cpc single in conduit for high earth leakage current from all those ballasts?

Cheers.....

 

[kieronious]

Or you could use a contactor to switch the load. But switching in banks as Rob said would be the best option.

Do you have to do the cable sizing as well?