help needed please( wiring up cooltube)

Hi , I've just brought a cooltube but the flex was not attached and there are no markings regarding +/-. As you look where the lamp screws in does anyone know weather the middle terminal is + and the outside - ? Any help would be great as my room is getting v hot and the flex on my 600w lamp is starting to melt.

here are the pic's

it doesn't matter you can connect theme to either side

light bulbs are usually not polarized

they dont care which way the current is running through them they are happy as can be since the fillament will still heat up

Nice one . Ill just wait for it to cool down then get it sorted ready for my light cycle in the morning.Thanks for your help. here's a pic of my setup so far its not quite finnished yet due to lack of time but i'll get the rest of my ventilation sorted tomorrow and drop the light right down .