Question about old 400w MH and safety.

I got this old (made in '95) MH ballast from a freind. It didnt have a power cord, so I cut a household extension cord rated for 1875 watts and wired it up. The ballast only had two wires for the power cord and no ground wire. I used this light for about a month at 20/4 for about a month with no problems. I bought a new 600 hps system, but now need a supplement to that. I hope someone can tell me if this MH is safe to use for a month of 12/12, if I should use heavier cord, and if it is possible without much effort to add a ground wire to the ballast. One more thing I bought a new 400 MH bulb and it no longer works, worked for a week, but the old one still works. The new bulb that doesnt work is a cheap brand called Magnatron it cost $10 new. The old one that works is a phillips. I think the magnatron may just be a cheap and crappy bulb.

Spend some of the money you will save on buying weed by getting a safe setup, ok? The bulb is so old it probably doesnt even put out the right amount of lumens to be really meaningful. Just go to the grow store, buy a bulb and a socket and that'll set you back $100. If you cant afford the $100, you should rethink your grow!