UK Lighting a Tennis Court

[pirate]

Can someone explain where the 10A comes from, please...?

 

[westward10]

Can someone explain where the 10A comes from, please...?

I think it runs from Walsall.

 

[Lucien Nunes]

how do i account for voltage losses raising the current draw?

The maximum permissible voltage drop is a small fraction of the supply voltage. We used to say 3% for lighting to maintain the efficiency of filament lamps but with electronic LED drivers that could be relaxed somewhat, as the internal regulation maintains the light output and the efficiency of the fixtures themselves is nearly constant over modest voltage variations. But too high a voltage drop can cause the drivers to malfunction, and it also represents wasted energy (as heat) that appears on the electricity bill. Therefore it makes sense to limit it to say 5-6%, or perhaps 10% at the very worst.

For constant power, the current is inversely proportional to the voltage, so if the absolute worst case is 10% drop, then likewise the absolute worst case is 10% current increase. It's an approximation but there are too many contributing variables involved, including cable temperature, driver efficiency curve, etc, to be worth refining the maths at all.

 

[Rockingit]

Can someone explain where the 10A comes from, please...?

That would be my fault - rounding up 1800W to be 10A for the sake of easier maths in this thread. The real figure would be around 8.7ish

 

[pirate]

Thanks for that! I was assuming that to be the case, but wasn't quite sure!