I would like to serve 8-400 watt metal-halide bulbs, 4 on each side of an outdoor covered sports court. Per vendor the lamps at 120v are 3.25 amps and max current 5.0 amps. I have a 100 amp, single phase 120/240v outdoor panel, and from this panel I want to go 100 feet to a new 60 amp panel adjacent to the court, and install 2-30 amp breakers to serve the 8 lamps. Out of this 60 amp panel I will also need to serve some restrooms and stage receptcles. Should I also install 2-30 amp fused safety disconnect switches to operate the lights? Or are the breakers in the 60 amp panel sufficent? Thank you.
Disconnect switches/metal-halide lamps
- Thread starter pelican
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- Massachusetts
Re: Disconnect switches/metal-halide lamps
No need for disconnect switches.
If it where me I would run these fixtures at 240 volts, at that voltage the load will be about 2 amps per fixture.
That would give you 8 amps on two circuits that even with voltage drop 12 AWG will be large enough for.
3.25 amps is to low a figure for 400 watt MH fixture at 120 volts.
No need for disconnect switches.
If it where me I would run these fixtures at 240 volts, at that voltage the load will be about 2 amps per fixture.
That would give you 8 amps on two circuits that even with voltage drop 12 AWG will be large enough for.
3.25 amps is to low a figure for 400 watt MH fixture at 120 volts.
Re: Disconnect switches/metal-halide lamps
Check several things. First, use the ballast wattage for your load calculation, check voltage drop as compared to the ballast voltage range. Second, the breaker rating and be sure they are O.K. for the fixtures, especially if used as switches.
Check several things. First, use the ballast wattage for your load calculation, check voltage drop as compared to the ballast voltage range. Second, the breaker rating and be sure they are O.K. for the fixtures, especially if used as switches.
Re: Disconnect switches/metal-halide lamps
1. Every 400 MH fixture I remember installing (many) draws 456 watts, or 3.8 amps at 120. If you choose not to ( or can't) wire these at 240 you'll need three 120 volt circuits to keep your wire size under #6. In fact, with only three lights on a 100' long 120 volt circuit #8 is still needed to mitigate voltage drop. 120 volts is terrible for lighting circuits.
2. I'm pretty sure most all new 20 and 30 amp 1-pole breakers are SWD rated, which they need to be if you use them to control the lights. A new requirement in the 2002 code ( 240.83(D) ) requires that breakers used as switches for high-intensity discharge lighting circuits shall be listed and shall be marked as "HID".
1. Every 400 MH fixture I remember installing (many) draws 456 watts, or 3.8 amps at 120. If you choose not to ( or can't) wire these at 240 you'll need three 120 volt circuits to keep your wire size under #6. In fact, with only three lights on a 100' long 120 volt circuit #8 is still needed to mitigate voltage drop. 120 volts is terrible for lighting circuits.
2. I'm pretty sure most all new 20 and 30 amp 1-pole breakers are SWD rated, which they need to be if you use them to control the lights. A new requirement in the 2002 code ( 240.83(D) ) requires that breakers used as switches for high-intensity discharge lighting circuits shall be listed and shall be marked as "HID".
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