# 400w bulb in 600w ballast



## Substorm (Apr 9, 2009)

Hey everyone just had a quick question about lighting.  I have a 600w HPS/MH switchable ballast and I just wanted to know if a 400w MH bulb would take 600w or 400w of electricity?


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## UKgirl420 (Apr 9, 2009)

well you are gonna have 200 watts going nowhere not a good idea imo eace:
u need to match the bulb to the ballast :48:


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## thc is good for me (Apr 12, 2009)

Yea thats a BIG NO GO you need to use a bulb that is made to be used with your ballast


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## la9 (Apr 15, 2009)

I've researched this out and still have not found the answer, not only that but no one wants to try it with their equipment. I almost tried it becuase someone said they had some old HID lighting they were going to throw away but when it came down to it, they would rather throw it away than let someone use it for testing purposes.

The theory is that you cannot run a smaller bulb in a bigger ballast, the bulbs have a negative resistance which will over heat the ballast and possibly explode the bulb, due to pulling excessive current thru the bulb, either case is not what you want.

On the other side of the equation, in theory, although I read some cities do this to save money. You are supposed to be able to run a bigger bulb in a smaller ballast. For example a 1000 watt bulb should work in a 600 watt ballast. The 1000 watt bulb will still only burn at 600 watt brightness but the bulb is supposed to last longer and stay in the correct spectrum longer due to it being built to burn 1000 watts instead of 600. I also think 1000 watt bulbs are cheaper. I forget how much longer the bulb was supposed to last but it was enough to make it worthwhile.

For the time being, until somehow we end up with actual equipment to test, the best thing to do is match the ballast to the bulb.

Also note if you think you will get a straight answer by writing a ballast manufacturer, you are wrong, due to all the liability lawsuits nowadays they will only tell you to match the bulbs to the ballasts.

Another thing to consider that with all the DIY yourself stuff on the web and it's hard to find any info on using diferent size bulbs that it is still the best idea to match them up.


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## Newbud (Apr 15, 2009)

> High intensity discharge lamps (HID) can also be managed as universal waste. Lead is found in the base of the lamps and they also contain mercury. HID lamps are used for outdoor lighting, interior lighting in stores or warehouses, and some specialty uses. They include:
> 
> Mercury vapor
> Metal halide
> ...



Wouldn't advise anyone to try it. Imagine one popping in your grow


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