Voltage drop on lighting circuit in warehouse

[s100cky]

Hello All!

I was hoping to have some help from some of the savvy bunch if at all possible? I am currently pricing a largish job for a client of mine. It involves changing some warehouse lighting (currently fluourcesents to 400W metal halide low bays. The warehouse is 75 meters long, and 50meters wide (remember this it will be useful later!)

So I thought id blow the dust of my IEE electrical installation design guide (as I havnt really looked at this since college), and started playing around with some calculations

 

[Sidewinder]

Why are you changing the lights?

I have read a document that says certain discharge lamps will be discontinued very shortly.

I may well be wrong, but I thought that MH were one of them.

Mind I thought that they were some of the more energy efficient types.

You need to consider the factor for discharge lighting.

You also need to consider the current along the circuit run.

 

[NozSpark]

Lets say you have 4 lights on a circuit 20m apart and 20m from the DB

The first 20m will have the load of 4 lights, the second 20m 3 lights, the third 20m 2 lights and the last 20m only 1 light

Your mistake is that you are designing it as if all the load is at the end of the circuit

 

[m4tty]

Use LED low bays

Do you know how much these are canoe?

 

[Evans Electric]

Get the efficiency details from the makers ( Gear losses etc) which should help your calcs.

10mm is just silly.

 

[s100cky]

Hi sidewinder,

I am changing the lights as the old ones are very few and far apart. A mixture between twin fluorescents (8ft)MH and alot of duff stuff.

I would be suprised if MH are going to be discontinued yet, any replacements ie LEDs still seem too dear to be viable.

I applied a discharge lighting factor of 1.8 (400x1.8)

the currrent along the circuit is the element i needed help with, i believe ive sorted it now thanks to a brain jerk for some members.

Cheers Guys

---------- Post Auto-Merged at 23:04 ---------- Previous post was made at 23:03 ----------

10mm is clearly silly, dont much fancy terminating that into a Low bay!

---------- Post Auto-Merged at 23:05 ---------- Previous post was made at 23:04 ----------

Use LED low bays

I say yes, the client he say NO!. I would think this would be a good idea, have you got any idea on unit cost. i need 80!

 

[SLIPSHOD & SLAPDASH]

Yes, have you deep pockets ?

And short arms ?

 

[Sidewinder]

Have you done a proper payback calculation on the LED fittings vs other options?

 

[NozSpark]

IIRC there are grants available for switching to energy saving lighting etc