I've just replaced some old chrome spotlight surrounds in the bathroom and am wondering how the transformer outputs need to be connected to the new bulb holders. In the loft above there is a 12v transformer which supplies each spotlight, but the transformer outputs are two white wires and are not labelled as L or N etc - does it matter which way round these are connected to the buld holder? Bulbs are 12v 50w (the type that have 2 thin pins which push into the holder). Thanks.