I have a new pole building. I have 5 high bay lights which I have purchased previously. They can be wired 110 or 220. Any benefit to one over the other? I am going to put them all on the same switch. Could anyone draw a basic diagram to wire them to the switch using 220v? Do I daisy chain from one to the other or need a box for each one?
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wiring lights question
- Thread starter mooch
- Start date
Charles (in GA)
Well-known member
What kind of lights are they? 250watt. 400 watt? Metal Halide? Sodium? Mercury Vapor?
If 400 watt anything, they will draw too much to put all five on one switch. 400 watt Metal halides draw right at 4.0 amps. A lighting circuit is generally considered continuous (over 3 hr) use by the code, and needs to be limited to 80% of max. Thus 20 amp circuit is limited to 16 amps, and 15 amp circuit is limited to 12 amps max. This is all if connected at 120v.
If you wired for 240v, you halve the amp draw, and all could be put on a 240v circuit. For wiring 240v, you need a double pole switch, as you need to switch BOTH sides of the circuit, and of course, you will need to use a double pole circuit breaker. The lights should have separate pigtails inside them with markings or flags on the wires for which wire is 120v and which is 240v (probably one in there for 277v also). Cap off any unused pigtails.
The wire attached to such fixtures will need to be temp rated to at least what is on the placard on the lights, usually 90°C, so most Romex type wire is not acceptable for this.
The wire connections to the lights is no different for 120v or 240v (other than using the correct pigtail in the fixture) but the circuit at the switch needs to have both sides switched, thus the DP switch. You also need to be sure of the amp rating of the switch.
Charles
If 400 watt anything, they will draw too much to put all five on one switch. 400 watt Metal halides draw right at 4.0 amps. A lighting circuit is generally considered continuous (over 3 hr) use by the code, and needs to be limited to 80% of max. Thus 20 amp circuit is limited to 16 amps, and 15 amp circuit is limited to 12 amps max. This is all if connected at 120v.
If you wired for 240v, you halve the amp draw, and all could be put on a 240v circuit. For wiring 240v, you need a double pole switch, as you need to switch BOTH sides of the circuit, and of course, you will need to use a double pole circuit breaker. The lights should have separate pigtails inside them with markings or flags on the wires for which wire is 120v and which is 240v (probably one in there for 277v also). Cap off any unused pigtails.
The wire attached to such fixtures will need to be temp rated to at least what is on the placard on the lights, usually 90°C, so most Romex type wire is not acceptable for this.
The wire connections to the lights is no different for 120v or 240v (other than using the correct pigtail in the fixture) but the circuit at the switch needs to have both sides switched, thus the DP switch. You also need to be sure of the amp rating of the switch.
Charles
I will check how many watts but I remember they draw 2.0 amps wired at 240v. So 5 lights would be 10 amps. As far as different wire, can I use 12-2 to the switch and then a box on the ceiling and then the temp rated wire from there out to the lights? Can I just daisy chain all the lights from one box?
thanks
thanks
nehog
Well-known member
I will check how many watts but I remember they draw 2.0 amps wired at 240v. So 5 lights would be 10 amps. As far as different wire, can I use 12-2 to the switch and then a box on the ceiling and then the temp rated wire from there out to the lights? Can I just daisy chain all the lights from one box?
thanks
Using 240 volts...
1. Sound like 400 watt lamps, probably metal-halide (HID) fixtures.
2. At 2 amps per fixture, five fixtures is 10 amps, and 12 AWG is good for 20 amps so you are set there.
3. Yes use wire rated for the fixture from the box to the fixture.
4. Yes, daisy chain from one to the other is OK.
If this is an attached to living space building, you cannot (by code) use 240 volt fixtures.