LED 120v-277v... It was installed on a 240v circuit. Boss said it's 120v through 277v. Clarification, please.

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DukeSilver

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I understand 120v is a hot and neutral, 277v is a hot and neurtal but 240v is two hots and yes it is only 120v to ground but it just feels wrong. The lights worked fine but I was surprised to find 240v in a medium base.
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In lamps with an Edison base the screw shell is intended to be connected to a grounded conductor, apparently for safety reasons. That way when someone is installing or removing a lamp, if someone touches the screw base and an equipment ground they will not be shocked if the light switch is left ON. In Europe and many other countries they have 230V from hot to neutral, and they use E27 medium base bulbs.
As stated above, the lamp itself would not be affected by the voltage relative to the equipment ground but only by the voltage across its terminals.
 
I would find this as a potential safety issue in that the Edison base build type the outer shell can be energized as even when bulb is only partially inserted unlike if the outer shell was properly attached to the neutral.
Code does make a reference that would seem to indicate your installation is potentially acceptable, but only if switching is correctly done per 410.93 or 410.104(B) that requires all ungrounded conductors be simultaneously disconnected.

You don't reference the location or if residential or otherwise, I would be hesitant to make such an installation where the changing of the bulb would be done by a "less than qualified" person. Ie the home owner.
 
Fred B said:
I would find this as a potential safety issue in that the Edison base build type the outer shell can be energized as even when bulb is only partially inserted unlike if the outer shell was properly attached to the neutral.
Code does make a reference that would seem to indicate your installation is potentially acceptable, but only if switching is correctly done per 410.93 or 410.104(B) that requires all ungrounded conductors be simultaneously disconnected.

You don't reference the location or if residential or otherwise, I would be hesitant to make such an installation where the changing of the bulb would be done by a "less than qualified" person. Ie the home owner.
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Though somewhat rare, 230 volt Edison base incandescent lamps do exist. I might even have one or two in the shop that have never been used, I know at one time I did have some anyway. We used to use them in night lights/security lights and other applications where low light levels were acceptable yet owners didn't want to have to change bulbs every month or so. By applying only ~120 volts to them they only used about 1/4 of watt rating and lasted seemingly forever. So you could put in a 100 watt 230 volt lamp on 120 volts and get similar light output to a 25 watt lamp but may never need to change the lamp in the lifetime of the installation in some cases.

Then there is mogul base lamps commonly available in 120, 240 and 277 volts, or at least once was. Last 30-40 years most mogul base lamps were utilized with HID luminaires, but before those were popular there were incandescent lamps with mogul base in the 500 to 1000 watt ranges
 
kwired said:
Then there is mogul base lamps commonly available in 120, 240 and 277 volts, or at least once was. Last 30-40 years most mogul base lamps were utilized with HID luminaires, but before those were popular there were incandescent lamps with mogul base in the 500 to 1000 watt ranges
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I have an old baseball stadium light that has a 1,500w, 120v mogul-based socket and bulb.
 
LarryFine said:
I have an old baseball stadium light that has a 1,500w, 120v mogul-based socket and bulb.
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I scrapped a bunch of fixtures a month ago, one had the same lamp installed.

Somebody was writing about "230V" incandescent lamps, on a 240V supply they would not last the rated life, somewhere have a 6 pack of Sylvania 100W 250V lamps, have no idea what to do with them.
 
norcal said:
I scrapped a bunch of fixtures a month ago, one had the same lamp installed.

Somebody was writing about "230V" incandescent lamps, on a 240V supply they would not last the rated life, somewhere have a 6 pack of Sylvania 100W 250V lamps, have no idea what to do with them.
Click to expand...
I've seen them (250v lamps) used for ground-fault monitors at older industrial facilities (unground systems) and as "monitor" lights on 120v circuits...some have been illuminated for decades :)
The old industrial facilities can be fascinating.
 
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