One street over from us, the neutral line between a couple poles completely broke during the hurricane. We got power back to the neighborhood yesterday evening. I was surprised to see everything downstream of that broken neutral got their power back. Purely out of curiosity, is that line not required for power to continue down the circuit to each house?

Depends on a lot of factors. Either the homes are not run off of a line-to-neutral primary transformer (could be line-to-line primary), or what broke was not a neutral conductor.

That line is really a ground. Power lines are generally in a delta configuration where you just have three phase conductors, or hots. For residential applications, the utility company takes one of those phases and feeds a center tapped transformer to create the 120/240.

One of the three phases goes to a center tapped transformer and that transformer creates two phases out of it for residential?

BrazosDog02 said:

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One of the three phases goes to a center tapped transformer and that transformer creates two phases out of it for residential?

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Yes, although in many strictly residential areas it's pretty common to only have single-phase distribution on the primary side. My parents house in "old" N Dallas inside 635 has three phase service (hi leg delta) but my slightly newer house 10 miles north only has single phase, with no prayer of three phase being available because the distribution isn't there.

Edit: the "two phases" in typical residential setting is called "split single phase." You wind up with two hot legs (120 volts line to neutral) that are 180 degrees out of phase with each other. Hot to hot then gets you 240v. In a commercial/industrial setting with three phase service, the three hot legs are 120 degrees out phase with each other. Hot to hot gets you 208 volts.

Thanks for the explanations. I've learned a lot this week between helping neighbors with septic pumps or generators of all types!

akaggie05 said:

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In a commercial/industrial setting with three phase service, the three hot legs are 120 degrees out phase with each other. Hot to hot gets you 208 volts.

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Coincidentally, on a Hi-Leg Open Delta, you get 120 L-N on two of the phases and 208 L-N on the high leg.

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That line is really a ground. Power lines are generally in a delta configuration where you just have three phase conductors, or hots. For residential applications, the utility company takes one of those phases and feeds a center tapped transformer to create the 120/240.

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Isn't that line typically grounded at each pole as well and the purpose of it is for lightening protection (it's the line at the very top, correct)?

Most wood poles have a ground wire and a ground plate at the butt of the pole down in the ground. Grounding is more about reducing differences in potential and general safety than lighting protection. Grounding something won't prevent lightning strikes, it might just give it a better place to go. Power lines also have lightning arresters that act like pressure relief valves. They don't conduct at the normal rated voltage, but "turn on" and conduct at a given over voltage. It shunts the lightning strike, surge, etc straight to ground like your water heater T&P valve.