2.5 HMI off 30amp twist household

Michael K Bergstrom · January 26, 2008

The gennie we had for our shoot to run a 2.5 HMI off went down, we have no power from the bates plug, and our shoot is tonight. Don't know if we can get this back up and running in time. The location is right outside a house, with a 30 amp in the laundry room, wondering if it's possible to run the 2.5 off this plug? the 2.5 ballast off course is bates. Any help is appreciated.

Stuart Brereton · January 26, 2008

Well, 2.5kw divided by 110 volts equals about 23 amps, so you should be fine.

Michael Collier · January 26, 2008

how much should we factor in cable power loss over a run? It seems that the longer we throw the cable out, the more we loose, esp. when striking. I need to pick up gear in 45 minutes......I am going to murder that murphy AND his law.....thats what we need to rename this short.....'screw murphy! he ain't keeping me down!'

If anyone knows if this power will work over a long run, its starting to get desperate (and dark and cold outside....which means we must be close to slate)

also to check my understanding those twist hookups are nominaly 220v not 110 right?

robert duke · January 26, 2008

probably to late to help but meter the plug,

2500's can be closer to 28amps, still clear enough for the breaker.

how long a run, look at the Harry box book.

you can pull 110 out of a 220 outlet, just dont use one of the power legs.

JD Hartman · January 28, 2008

probably to late to help but meter the plug,
2500's can be closer to 28amps, still clear enough for the breaker.

how long a run, look at the Harry box book.

you can pull 110 out of a 220 outlet, just dont use one of the power legs.

If the outlet is 220vac and has three blades, you can't safely split it into into two 110vac lines. It has two current carrying conductor and a ground but no neutral. The NEC forbids the use of a ground as a current carrying conductor. Don't tell me that there are guys building adapters to split 220v dryer or range plugs into two 110 circuits. Without a neutral conductor, these things are inherently un-safe.

Your 2.5 ballast should be able to run on 220 volts and probably has an auto-voltage detect. Check the specification plate, build a twistlock to bates adapter.

Brad Dickson · January 30, 2008

As noted in a previous post many ballasts are designed for world use. They will have an operational voltage range they can work in and a frequency they can work in. This should be noted on the ballast itself along with other ratings. Some ballast will adjust to the various ranges automatically while some older units required you to adjust the setting via a switch setting. Best would be to gain access to the ballast manufacturer if the information is not available.

You may also find that some breakers will trip even though the current draw is below the rated amperage of the HMI. This is some times dependent upon the breaker type and can happen upon striking the HMI. GFI breakers can have problems with HMI units, thus causing them to trip.