Baancing Three Phase

[rolyberkin]

Hi All

I am doing an assignment and wondered on a practical/safety note if there are any issues in balancing luminaires over three phases in the same office area fed by a three phase installation, say if I had 21 lights should I put 7 on each phase or stick to one phase and just split them over a few mcb's to ensure some light in the event of a trip? Hope this makes sense?

 

[Simonslimline]

One thing i remember being taught at college was the placing of the luminaires if split across the phases due to stroboscopic effect.

Generally best to balance the load across the phases though i would say.

I am sure one of the more experienced members can give you some better advice though.

 

[i=p/u]

as above split over phases , try not to have 400v at accessories if can be helped

 

[rolyberkin]

as above split over phases , try not to have 400v at accessories if can be helped

Thanks, saves me a lot of re drawing!

 

[Marvo]

In general I'd say balance across 3 phases but if it was 21 LED light points like in a house I'm not sure it would warrant the extra installation expense of balancing a load of a < an Amp across 3 circuits.....

 

[rolyberkin]

In general I'd say balance across 3 phases but if it was 21 LED light points like in a house I'm not sure it would warrant the extra installation expense of balancing a load of a < an Amp across 3 circuits.....

It looks pretty on a drawing though

 

[Darkwood]

Balancing phases comes down to the whole install and not the individual office.
Having 400v between reachable points was a crap reg and has been since updated to voltage to earth which is always 230v standard.
Stroboscopic effect is becoming a past issue as all flourescents now have to be electronic ballasts and it was the laminated heavy ballasts that could create this effect, although this effect has to be taken into account for other inductive lighting with laminated ballasts that haven't been culled by the energy efficient EU rules (SON, Metal hallide etc).
In a large install, balancing the lighting is essential as it can be 60+% of the power usage but has more to do with having available 3ph capacity for any new load as oppose to efficiency.

Your original concerns though will probably suit what your tutor is after, balancing them, redunancy if a circuit trips, then you still have lighting.

@Simonslimline - stroboscopic effect is only relevant to rotating machinery or other fast moving equipment where the frequency of the fitting can cancel out the visual aspect of movement and 'say' a moving gear on a machine look like its stationary thus create an obvious hazzard.