You'll have to either:

1. Get a 120 to 277 volt or 240 to 277 volt transformer for the lights,

2. Figure out that (not whether) there is a ballast tap allowing the fixture to accept 120 or 240 volts. You may have to contact the manufacturer and/or get a schematic diagram.

 

from what I can tell, the company is no longer in business. =(

Where would I find a ballast tap that will do what I need it to?

 

it really sounds like you have single voltage ballasts so, you can either buy new ballasts that are 120 volt or you can use a transformer which would make no sense so you either get the ballasts or toss the lights.

 

Why does anyone need 400 watt lights in a house?????????:whistling2:

 

Only need a couple three lights to light the entire house? :thumbup:

 

If a 277 volt HPS fixture is connected to 240 volts, it'll very likely work just fine. Most of these fixtures use a CWA (Constant Wattage Autotransformer) ballast. This type of ballast does pretty well at reduced voltage.

Since it'll be operating at about 15% less voltage, you can expect about a 10% decrease in light, and about a 20% reduction in lamp life.

If the ballast is a HX (High Reactance) type, it'll most likely light up OK, run for a few minutes, the go out. 5-10 minutes later it'll re-light, then go out. This type of ballast needs the correct input voltage.

The only way to know for sure is to look at the connection diagram. Since that is difficult, if not impossible, hook one of them up and see what happens. There's no fire danger, the ballast and lamp both run cooler at reduced voltage.

Rob

 

A 400w light is probably going to use more power then it will ever pay off in tomatoes & herbs

Is it a Halogen light?
400w might be even too much light depending upon how far away it will be from what you are growing
Tomatoes grow tall, other herbs will be shorter - so need to balance location of the light

 

A 400 watt HPS will use about 450-500 watts of power. If it's 277 volt, and operated at 240 volts, it'll use right around 400 watts.

If your power costs $0.15 per KWH (Kilowatt hour), it'll cost about 7 cents per hour.

If it operates only at night (like parking lot lights), each fixture will cost about $21 per month.

Like Scuba said....them's pretty spendy greens!

Rob

 

One 400 watt fixture might be used to light up an entire yard as opposed to installing multiple smaller wattage fixtures. For best results it should be mounted quite high up, probably at the eaves of a 2 story house if not higher.

400 watts is a common size for street lights. Those in 400 watt mercury and 400 watt sodium are usually mounted about 35 feet above the road although they may also be found on lower bracket arms that were installed with an older light such as an incandescent.

A ballast tap is generally another lug terminal or pigtail on the ballast for connecting up the power. Technically it is a connection to somewhere in the middle of the coil, and you select two of the connections, end(s) or middle(s) which two are meant to go with the supply voltage.

 

AllanJ He is Growing " Tomatoes" In his House :laughing:

 

Why not take a photo and upload it here so we can able indentify it and one of us will able tell which type of luminaire set up you have.

But with 400 watt HPS that typically draw 460 watts no matter which voltage you are using and this will crank out pretty serious amout of light it will dish out however it is bright orange colour as you see in streetlight luminaire.

There is a specal type of HPS bulb that will used for greenhouse useage and that use standard 400 w ballast set up IIRC it called ARGO not sure if still make them or not.

Now speaking of ballast as other guys they are right on target either add a transfomer to boost it up or swap the ballast to either 120 volts or get one with multi tap { most will useally get in MT (multitap) }

with MT set up you can run either 120 volts or 240 volts however if you have 4 400 w HPS that is the limit on 120 v 20 amp circuit on 240 volts that will be 8 of them.

Yeah there is always a way to get into the ballast housing area and most case you will see a wiring diagram for correct connection set up.

If you have more question just holler one of us will help ya.

Merci,Marc