Any good ideas?

[Rockingit]

Got a job to price up that's a bit tricky trying to make economical - if anyone's got a good idea then there's beer to be had!

Big warehouse environment, needs a complete lighting revamp and new install of many (haven't finished the planning but around 200 odd) 6' strips (as per customer, I have also suggested looking at LED). Trouble is that it's going to have to be done in conduit not trunking, and the customer wants it all to be multi-zone switched so that it's only the specific pick area that's lit up at any one time, plus the usual EM's etc.

So, I've got 25mm conduit (maybe 32 at a push), most likely PVC for cost, a heap of fluorescents, bunch of switching, and a BRB that tells me I need to use 16mm singles for voltage drop compliance over 200m (length of warehouse from the main DB). Using 4mm single over that length you lose 2.2v per amp, so it's just about possible to squeeze 2kW and more or less be within the 5% but I'm then wondering about the inductance spikes of that many fluoro's going on and off.

The only immediate thing I can think of is to divide the whole lot up into a load of submains and use separate armoureds to supply each one, but it's going to push the cost way up and I don't think the customer will stand it.

 

[telectrix]

3% VD for lighting, not 5%. your suggestion of a couple of sub-mains is probably the best solution.

 

[Rockingit]

Got a better idea! Am going to install micro treadmills all over the place so that the mice can produce some eco power!

 

[jumpin jax]

without doing any maths, what about a lighting ring in 4mm tapping off for switch gear or put one sub main in the middle of the warehouse or one at each end and make a lighting ring switched thru contactors

 

[johnboy6083]

Are you reducing the load over the circuit mate? So in other words the feed to the last light will only be carrying the load of that light, and can be sized smaller as a result. Use the adiabatic to size the CPC to save a few quid and lessen the cable in the tube. Just a few of my thoughts.

 

[Rockingit]

I think: steel conduit to use as cpc (need to double check the adiabatic on that once my numbers are finished but it 'feels' OK), run a 16mm/2 armoured+10mm cpc out to 2 x submains at the start and very end of the run, then do a 'normal' loop circuit(s) in 4mm running towards each other in the middle. Metal clad HF fluoro's to ease the switching load and get better running costs, as well as being able to dispense with a separate cpc to the fixture (so long as the conduit gets properly threaded into the body).

Right then, anyone like to make me an offer on 4km of steel conduit and boxes???

Incidentally, 6.4 table 4aB - the small print does allow you a whole extra 0.005% per metre beyond 100m in lighting circuits, so long as the maximum is 0.5%. A whole extra 1.15 volts! Hey, those guys at the IET really know how to spoil us.

 

[johnboy6083]

have you used the 1.8 factor for the Ib in the volt drop calcs. if so, then is there any information available from the manufacturerto reduce that? you may be suprised, or you may be told no, its 1.8 and thats it.
That would be a nice tubing job that. Get a scissor lift big enough to have a bender on it lol.

 

[Rockingit]

Get a scissor lift big enough to have a bender on it lol.

Er, I missed out about that bit......only 20" wide gangways - no room for plant!! I think 24' zarges will just about cut it for most, thereafter it's a good job I do rope access!!