Exterior Lighitng

[Mike01]

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Ok I understand this would create a delta connection but how would removing one phase create a series connection between the other two? Does this mean this arrangement will not operate properly? Where can I find a wiring diagram similar to this to help me visualize it.

 

[crossman]

Here ya go: If contact B is open, then A phase and C phase feed light 3 directly with 480 volts. A phase will also feed light 1, through the wiring to light 2, through light 2 to C phase. Both lights 1 and 2 will have voltage on them, but it will be 480 in series with the 2 lights, giving half voltage on each. If there are differing numbers of lights/impedances at 1 and 2 in the diagram, the voltage will not actually split exactly in half. Perhaps one load could see 200 volts, the other 280 volts, or whatever.

 

[LarryFine]

Well I certainly feel like a dolt.


My apologies.

I really did draw it out and still did not see it.

Don't worry, Bob. We still love ya! :smile:

 

[rkess]

If you had a 480v-3ph lighting circuit and each pole with 2 luminaires was phased per head per pole and you interrupted one of the phases what would happen? I have come across a wiring diagram that shows a contactor interrupt ring the b phase of the three phase exterior lighting circuit to decrease the number of luminaires on after 1:00am but what would happen to the ballasts / luminaires that were still served by the one energized phase? Would this arrangement work?:-?

Im thinking that there is only two heads on the pole one head is wired
across phases "a" and "c" the other head is phase "b" and either "a" or "c"