How many watts does a 600 watt hps consumes?

[Medfinder]

A ballast is a current limiter, that's their purpose. Bulbs do not determine current (once they are fully started). A 250 watt hps bulb on a 1k ballast will pull 1000watts (until the bulb completely self destructs).

A old bulb puts out less light and a worse spectrum, but the ballast is still in charge.

A lamp cord heating up will not change your current draw. It will just be using some of those 600 watts to make heat. So same electrical usage, just less going to your bulb. No ballast is smart enough to try to compensate. Fortunately, unless you have a 300 foot cord that is heating up to red hot, it's a pretty small difference, but it's always good to keep them out of light. They last longer if they are cool and not getting UV.

yup..lost a 600 because i set at the wrong dim setting fused the bulb.